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Bi Q, Dickerman BA, Nguyen HQ, Martin ET, Gaglani M, Wernli KJ, Balasubramani G, Flannery B, Lipsitch M, Cobey S. Reduced effectiveness of repeat influenza vaccination: distinguishing among within-season waning, recent clinical infection, and subclinical infection. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2024:2023.03.12.23287173. [PMID: 37016669 PMCID: PMC10071822 DOI: 10.1101/2023.03.12.23287173] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 06/19/2023]
Abstract
Studies have reported that prior-season influenza vaccination is associated with higher risk of clinical influenza infection among vaccinees. This effect might arise from incomplete consideration of within-season waning and recent infection. Using data from the US Flu Vaccine Effectiveness (VE) Network (2011-2012 to 2018-2019 seasons), we found that repeat vaccinees were vaccinated earlier in a season by one week. After accounting for waning VE, repeat vaccinees were still more likely to test positive for A(H3N2) (OR=1.11, 95%CI:1.02-1.21) but not for influenza B or A(H1N1). We found that clinical infection influenced individuals' decision to vaccinate in the following season while protecting against clinical infection of the same (sub)type. However, adjusting for recent clinical infections did not strongly influence the estimated effect of prior-season vaccination. In contrast, we found that adjusting for subclinical infection could theoretically attenuate this effect. Additional investigation is needed to determine the impact of subclinical infections on VE.
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Affiliation(s)
- Qifang Bi
- University of Chicago, Chicago, Illinois, USA
| | | | - Huong Q. Nguyen
- Center for Clinical Epidemiology & Population Health, Marshfield Clinic Research Institute, Marshfield, Wisconsin, USA
| | - Emily T. Martin
- University of Michigan School of Public Health, Ann Arbor, Michigan, USA
| | - Manjusha Gaglani
- Baylor Scott & White Health, Temple, Texas, USA
- Texas A&M University College of Medicine, Temple, Texas, USA
| | - Karen J. Wernli
- Kaiser Permanente Bernard J. Tyson School of Medicine, Seattle, Washington, USA
| | - G.K. Balasubramani
- University of Pittsburgh School of Public Health, Pittsburgh, Pennsylvania, USA
| | - Brendan Flannery
- National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA, US
| | - Marc Lipsitch
- Harvard T.H. Chan School of Public Health, Boston, Massachusetts, USA
| | - Sarah Cobey
- University of Chicago, Chicago, Illinois, USA
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Hu W, Sjoberg PA, Fries AC, DeMarcus LS, Robbins AS. Waning Vaccine Protection against Influenza among Department of Defense Adult Beneficiaries in the United States, 2016–2017 through 2019–2020 Influenza Seasons. Vaccines (Basel) 2022; 10:vaccines10060888. [PMID: 35746496 PMCID: PMC9229659 DOI: 10.3390/vaccines10060888] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2022] [Revised: 05/29/2022] [Accepted: 05/30/2022] [Indexed: 02/05/2023] Open
Abstract
The objective of this study was to assess inactivated influenza vaccine effectiveness (VE) by time since vaccination in adults aged ≥ 18 years using a test-negative design. All data were obtained from the US Department of Defense Global Respiratory Pathogen Surveillance Program over four influenza seasons, from 2016–2017 through 2019–2020. Analyses were performed to estimate VE using a generalized linear mixed model with logit link and binomial distribution. The adjusted overall VE against any medically attended, laboratory-confirmed influenza decreased from 50% (95% confidence interval (CI): 41–58%) in adults vaccinated 14 to 74 days prior to the onset of influenza-like illness (ILI), to 39% (95% CI: 31–47%) in adults vaccinated 75 to 134 days prior to the onset of ILI, then to 17% (95% CI: 0–32%) in adults vaccinated 135 to 194 days prior to the onset of ILI. The pattern and magnitude of VE change with increasing time since vaccination differed by influenza (sub)types. Compared to VE against influenza A(H1N1)pdm09 and influenza B, the decrease of VE against influenza A(H3N2) was more pronounced with increasing time since vaccination. In conclusion, based on the analysis of 2536 influenza-positive cases identified from 7058 adults over multiple influenza seasons, the effectiveness of inactivated influenza vaccine wanes within 180 days after 14 days of influenza vaccination.
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Affiliation(s)
- Wenping Hu
- The Department of Defense Global Emerging Infections Surveillance Branch, Armed Forces Health Surveillance Division, Wright-Patterson Air Force Base, Dayton, OH 45433, USA; (P.A.S.); (L.S.D.); (A.S.R.)
- JYG Innovations, LLC, Dayton, OH 45414, USA
- Correspondence:
| | - Paul A. Sjoberg
- The Department of Defense Global Emerging Infections Surveillance Branch, Armed Forces Health Surveillance Division, Wright-Patterson Air Force Base, Dayton, OH 45433, USA; (P.A.S.); (L.S.D.); (A.S.R.)
- JYG Innovations, LLC, Dayton, OH 45414, USA
| | - Anthony C. Fries
- U.S. Air Force School of Aerospace Medicine, Wright-Patterson Air Force Base, Dayton, OH 45433, USA;
| | - Laurie S. DeMarcus
- The Department of Defense Global Emerging Infections Surveillance Branch, Armed Forces Health Surveillance Division, Wright-Patterson Air Force Base, Dayton, OH 45433, USA; (P.A.S.); (L.S.D.); (A.S.R.)
- JYG Innovations, LLC, Dayton, OH 45414, USA
| | - Anthony S. Robbins
- The Department of Defense Global Emerging Infections Surveillance Branch, Armed Forces Health Surveillance Division, Wright-Patterson Air Force Base, Dayton, OH 45433, USA; (P.A.S.); (L.S.D.); (A.S.R.)
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3
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Okoli GN, Racovitan F, Abdulwahid T, Hyder SK, Lansbury L, Righolt CH, Mahmud SM, Nguyen-Van-Tam JS. Decline in Seasonal Influenza Vaccine Effectiveness With Vaccination Program Maturation: A Systematic Review and Meta-analysis. Open Forum Infect Dis 2021; 8:ofab069. [PMID: 33738320 PMCID: PMC7953658 DOI: 10.1093/ofid/ofab069] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 02/03/2021] [Indexed: 01/08/2023] Open
Abstract
BACKGROUND Evidence suggests that repeated influenza vaccination may reduce vaccine effectiveness (VE). Using influenza vaccination program maturation (PM; number of years since program inception) as a proxy for population-level repeated vaccination, we assessed the impact on pooled adjusted end-season VE estimates from outpatient test-negative design studies. METHODS We systematically searched and selected full-text publications from January 2011 to February 2020 (PROSPERO: CRD42017064595). We obtained influenza vaccination program inception year for each country and calculated PM as the difference between the year of deployment and year of program inception. We categorized PM into halves (cut at the median), tertiles, and quartiles and calculated pooled VE using an inverse-variance random-effects model. The primary outcome was pooled VE against all influenza. RESULTS We included 72 articles from 11 931 citations. Across the 3 categorizations of PM, a lower pooled VE against all influenza for all patients was observed with PM. Substantially higher reductions were observed in older adults (≥65 years). We observed similar results for A(H1N1)pdm09, A(H3N2), and influenza B. CONCLUSIONS The evidence suggests that influenza VE declines with vaccination PM. This study forms the basis for further discussions and examinations of the potential impact of vaccination PM on seasonal VE.
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Affiliation(s)
- George N Okoli
- College of Pharmacy, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
- Vaccine and Drug Evaluation Centre, University of Manitoba, Winnipeg, Manitoba, Canada
- George and Fay Yee Centre for Healthcare Innovation, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Florentin Racovitan
- Vaccine and Drug Evaluation Centre, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Tiba Abdulwahid
- George and Fay Yee Centre for Healthcare Innovation, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Syed K Hyder
- Department of Epidemiology and Public Health, University of Nottingham School of Medicine, Nottingham, United Kingdom
| | - Louise Lansbury
- Department of Epidemiology and Public Health, University of Nottingham School of Medicine, Nottingham, United Kingdom
| | - Christiaan H Righolt
- Vaccine and Drug Evaluation Centre, University of Manitoba, Winnipeg, Manitoba, Canada
- Community Health Sciences, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Salaheddin M Mahmud
- College of Pharmacy, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
- Vaccine and Drug Evaluation Centre, University of Manitoba, Winnipeg, Manitoba, Canada
- Community Health Sciences, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Jonathan S Nguyen-Van-Tam
- Department of Epidemiology and Public Health, University of Nottingham School of Medicine, Nottingham, United Kingdom
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4
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Okoli GN, Racovitan F, Abdulwahid T, Righolt CH, Mahmud SM. Variable seasonal influenza vaccine effectiveness across geographical regions, age groups and levels of vaccine antigenic similarity with circulating virus strains: A systematic review and meta-analysis of the evidence from test-negative design studies after the 2009/10 influenza pandemic. Vaccine 2021; 39:1225-1240. [PMID: 33494964 DOI: 10.1016/j.vaccine.2021.01.032] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 12/21/2020] [Accepted: 01/08/2021] [Indexed: 11/17/2022]
Abstract
BACKGROUND We examined the influence of some factors on seasonal influenza vaccine effectiveness (VE) from test-negative design (TND) studies. METHODS We systematically searched for full-text publications of VE against laboratory-confirmed influenza from TND studies in outpatient settings after the 2009/10 influenza pandemic. Two reviewers independently selected and extracted data from the included studies. We calculated pooled adjusted VE across geographical regions, age groups and levels of vaccine antigenic similarity with circulating virus strains, using an inverse variance, random-effects model. RESULTS We included 76 full-text articles from 11,931 citations. VE estimates against A(H1N1)pdm09, A(H3N2), influenza B, and all influenza were homogenous and point pooled VE higher in the Southern hemisphere compared with the Northern hemisphere. The difference in pooled VE between the Southern and Northern hemispheres was statistically significant for A(H3N2), influenza B, and all influenza. A consistent pattern was observed in pooled VE across both hemispheres and continents, with the highest point pooled VE being against A(H1N1)pdm09, followed by influenza B, and lowest against A(H3N2). A nearly consistent pattern was observed in pooled VE across age groups in the Northern hemisphere, with pooled VE mostly decreasing with age. Point pooled VE against A(H3N2), influenza B, and all influenza were statistically significantly higher when vaccine was antigenically similar to circulating virus strains compared with when antigenically dissimilar. Similar pattern was observed in the Northern hemisphere, but there was a lack of data from the Southern hemisphere. CONCLUSION Consistent patterns appear to exist in seasonal influenza VE across regions, age groups, and levels of vaccine antigenic similarity with circulating virus strains, with best vaccine performance against A(H1N1)pdm09 and worst against A(H3N2). The evidence highlights the need to consider geographical location, age, and vaccine antigenic similarity with circulating virus strains when designing and evaluating influenza VE studies.
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Affiliation(s)
- G N Okoli
- College of Pharmacy, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada; George and Fay Yee Centre for Healthcare Innovation, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada; Vaccine and Drug Evaluation Centre, University of Manitoba, Winnipeg, MB, Canada
| | - F Racovitan
- Vaccine and Drug Evaluation Centre, University of Manitoba, Winnipeg, MB, Canada
| | - T Abdulwahid
- George and Fay Yee Centre for Healthcare Innovation, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - C H Righolt
- Vaccine and Drug Evaluation Centre, University of Manitoba, Winnipeg, MB, Canada; Community Health Sciences, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - S M Mahmud
- College of Pharmacy, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada; Vaccine and Drug Evaluation Centre, University of Manitoba, Winnipeg, MB, Canada; Community Health Sciences, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada.
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5
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Ferdinands JM, Alyanak E, Reed C, Fry AM. Waning of Influenza Vaccine Protection: Exploring the Trade-offs of Changes in Vaccination Timing Among Older Adults. Clin Infect Dis 2021; 70:1550-1559. [PMID: 31257422 DOI: 10.1093/cid/ciz452] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2018] [Accepted: 05/30/2019] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND In recent studies of influenza vaccine effectiveness (VE), lower effectiveness with increasing time since vaccination was observed, raising the question of optimal vaccination timing. We sought to evaluate the estimated number of influenza-associated hospitalizations among older adults due to potential changes in vaccination timing. METHODS Using empirical data and a health state transition model, we estimated change in influenza-associated hospitalizations predicted to occur among the US population aged ≥65 years if vaccination were delayed until October 1. We assumed the vaccination timing, coverage, and effectiveness observed in 2012-2013 as a prototypical influenza season, approximately 7% monthly waning of VE, and that between 0% and 50% of individuals who usually get vaccinated earlier than October failed to get vaccinated. We also assessed change in influenza-associated hospitalizations if vaccination uptake shifted substantially toward August and September. RESULTS In a typical season, delaying vaccination until October increased influenza hospitalizations if more than 14% of older adults usually vaccinated in August and September failed to get vaccinated. The consequences of delayed vaccination depended heavily on influenza season timing, rate of waning, and overall VE. A shift toward vaccination in August and September led to, on average, an increase in influenza-associated hospitalizations, but this result was also sensitive to influenza season timing. CONCLUSIONS Consequences of delayed vaccination varied widely. Uncertainties about vaccine waning and effects of a delay on vaccine coverage suggest it is premature to change current vaccine recommendations, although it may be prudent to prevent a substantial shift toward early vaccination.
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Affiliation(s)
- Jill M Ferdinands
- Centers for Disease Control and Prevention, Influenza Division, Atlanta, Georgia
| | - Elif Alyanak
- Centers for Disease Control and Prevention, Influenza Division, Atlanta, Georgia.,ORISE Fellowship Program, Oak Ridge, Tennessee
| | - Carrie Reed
- Centers for Disease Control and Prevention, Influenza Division, Atlanta, Georgia
| | - Alicia M Fry
- Centers for Disease Control and Prevention, Influenza Division, Atlanta, Georgia
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6
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Okoli GN, Racovitan F, Righolt CH, Mahmud SM. Variations in Seasonal Influenza Vaccine Effectiveness due to Study Characteristics: A Systematic Review and Meta-analysis of Test-Negative Design Studies. Open Forum Infect Dis 2020; 7:ofaa177. [PMID: 32704509 PMCID: PMC7367680 DOI: 10.1093/ofid/ofaa177] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 05/19/2020] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND Study characteristics influence vaccine effectiveness (VE) estimation. We examined the influence of some of these on seasonal influenza VE estimates from test-negative design (TND) studies. METHODS We systematically searched bibliographic databases and websites for full-text publications of TND studies on VE against laboratory-confirmed seasonal influenza in outpatients after the 2009 pandemic influenza. We followed the Cochrane Handbook for Systematic Reviews of Interventions guidelines. We examined influence of source of vaccination information, respiratory specimen swab time, and covariate adjustment on VE. We calculated pooled adjusted VE against H1N1 and H3N2 influenza subtypes, influenza B, and all influenza using an inverse-variance random-effects model. RESULTS We included 70 full-text articles. Pooled VE against H1N1 and H3N2 influenza subtypes, influenza B, and all influenza was higher for studies that used self-reported vaccination than for those that used medical records. Pooled VE was higher with respiratory specimen collection within ≤7 days vs ≤4 days of symptom onset, but the opposite was observed for H1N1. Pooled VE was higher for studies that adjusted for age but not for medical conditions compared with those that adjusted for both. There was, however, a lack of statistical significance in almost all differences in pooled VE between compared groups. CONCLUSIONS The available evidence is not strong enough to conclude that influenza VE from TND studies varies by source of vaccination information, respiratory specimen swab time, or adjustment for age/medical conditions. The evidence is, however, indicative that these factors ought to be considered while designing or evaluating TND studies of influenza VE.
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Affiliation(s)
- George N Okoli
- George and Fay Yee Centre for Healthcare Innovation, Max Rady College of Medicine, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
- College of Pharmacy, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
- Vaccine and Drug Evaluation Centre, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Florentin Racovitan
- Vaccine and Drug Evaluation Centre, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Christiaan H Righolt
- Vaccine and Drug Evaluation Centre, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
| | - Salaheddin M Mahmud
- Vaccine and Drug Evaluation Centre, Rady Faculty of Health Sciences, University of Manitoba, Winnipeg, MB, Canada
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7
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Matsushita M, Arise K, Morimoto N, Takeuchi S. End-of-season outbreaks of nosocomial influenza caused by waning vaccine immunity. J Infect Prev 2020; 21:119-121. [PMID: 32494296 DOI: 10.1177/1757177420908012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Accepted: 01/29/2020] [Indexed: 11/17/2022] Open
Abstract
The waning of vaccine protection may be responsible for outbreaks toward the end of the influenza season. Three of five outbreaks occurred at the beginning of April following an interval of >100 days from the date of vaccination; the reported index case was a nurse or office worker, and >50% of those affected were healthcare workers. The results are consistent with intra-seasonal waning of vaccine immunity that resulted in outbreaks at the end of season.
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Affiliation(s)
| | - Kazumi Arise
- Department of Infection Control and Prevention, Kochi Medical School Hospital, Nankoku, Japan
| | - Norihito Morimoto
- Department of Infection Control and Prevention, Kochi Medical School Hospital, Nankoku, Japan.,Department of Clinical Laboratory, Kochi Medical School Hospital, Nankoku, Japan
| | - Seisho Takeuchi
- Department of Infection Control and Prevention, Kochi Medical School Hospital, Nankoku, Japan.,Department of General Medicine, Kochi Medical School Hospital, Nankoku, Japan
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8
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Rambhia KJ, Rambhia MT. Early Bird Gets the Flu: What Should Be Done About Waning Intraseasonal Immunity Against Seasonal Influenza? Clin Infect Dis 2020; 68:1235-1240. [PMID: 30169619 DOI: 10.1093/cid/ciy748] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2018] [Accepted: 08/24/2018] [Indexed: 11/14/2022] Open
Abstract
Recently published studies highlight the growing evidence for waning immunity within a single influenza season among vaccinated individuals. However, the public health efforts to increase vaccination coverage has resulted in earlier administration of vaccines. We find this approach to be suboptimal, as the benefits of early vaccination could be lost during peak months of influenza activity. Immunity generated by influenza vaccines is a complex scientific issue with many contributing factors. We advocate for a nuanced approach to the seasonal vaccine program- one that considers duration of immunity as much as it considers coverage. As we strive for higher rates of vaccination, we must also improve the efficacy of the vaccine and the public health programs that are responsible for distributing and administering the vaccine.
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Affiliation(s)
- Kunal J Rambhia
- Department of Biomedical Engineering, University of Michigan, Ann Arbor
| | - Milly T Rambhia
- Department of Anesthesiology, Northwestern Memorial Hospital, Chicago, Illinois
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9
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Chua H, Feng S, Lewnard JA, Sullivan SG, Blyth CC, Lipsitch M, Cowling BJ. The Use of Test-negative Controls to Monitor Vaccine Effectiveness: A Systematic Review of Methodology. Epidemiology 2020; 31:43-64. [PMID: 31609860 PMCID: PMC6888869 DOI: 10.1097/ede.0000000000001116] [Citation(s) in RCA: 85] [Impact Index Per Article: 21.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
BACKGROUND The test-negative design is an increasingly popular approach for estimating vaccine effectiveness (VE) due to its efficiency. This review aims to examine published test-negative design studies of VE and to explore similarities and differences in methodological choices for different diseases and vaccines. METHODS We conducted a systematic search on PubMed, Web of Science, and Medline, for studies reporting the effectiveness of any vaccines using a test-negative design. We screened titles and abstracts and reviewed full texts to identify relevant articles. We created a standardized form for each included article to extract information on the pathogen of interest, vaccine(s) being evaluated, study setting, clinical case definition, choices of cases and controls, and statistical approaches used to estimate VE. RESULTS We identified a total of 348 articles, including studies on VE against influenza virus (n = 253), rotavirus (n = 48), pneumococcus (n = 24), and nine other pathogens. Clinical case definitions used to enroll patients were similar by pathogens of interest but the sets of symptoms that defined them varied substantially. Controls could be those testing negative for the pathogen of interest, those testing positive for nonvaccine type of the pathogen of interest, or a subset of those testing positive for alternative pathogens. Most studies controlled for age, calendar time, and comorbidities. CONCLUSIONS Our review highlights similarities and differences in the application of the test-negative design that deserve further examination. If vaccination reduces disease severity in breakthrough infections, particular care must be taken in interpreting vaccine effectiveness estimates from test-negative design studies.
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Affiliation(s)
- Huiying Chua
- From the World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Shuo Feng
- From the World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Joseph A Lewnard
- Division of Epidemiology, School of Public Health, University of California, Berkeley, Berkeley, CA
| | - Sheena G Sullivan
- WHO Collaborating Centre for Reference and Research on Influenza, Royal Melbourne Hospital, and Doherty Department, University of Melbourne, at the Peter Doherty Institute for Infection and Immunity, Melbourne, Victoria, Australia
- Department of Epidemiology, Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA
- Centre for Epidemiology and Biostatistics, School of Population and Global Health, University of Melbourne, Melbourne, Victoria, Australia
| | - Christopher C Blyth
- Division of Paediatrics, School of Medicine, Faculty of Health and Medical Sciences, The University of Western Australia, Perth, Western Australia, Australia
- Wesfarmers Centre of Vaccines and Infectious Diseases, Telethon Kids Institute, Perth, Western Australia, Australia
- Department of Infectious Diseases, Perth Children's Hospital, Perth, Western Australia, Australia
| | - Marc Lipsitch
- Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, MA
- Center for Communicable Disease Dynamics, Harvard T. H. Chan School of Public Health, Boston, MA
| | - Benjamin J Cowling
- From the World Health Organization Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, The University of Hong Kong, Hong Kong Special Administrative Region, China
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10
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Rolfes MA, Flannery B, Chung JR, O’Halloran A, Garg S, Belongia EA, Gaglani M, Zimmerman RK, Jackson ML, Monto AS, Alden NB, Anderson E, Bennett NM, Billing L, Eckel S, Kirley PD, Lynfield R, Monroe ML, Spencer M, Spina N, Talbot HK, Thomas A, Torres SM, Yousey-Hindes K, Singleton JA, Patel M, Reed C, Fry AM. Effects of Influenza Vaccination in the United States During the 2017-2018 Influenza Season. Clin Infect Dis 2019; 69:1845-1853. [PMID: 30715278 PMCID: PMC7188082 DOI: 10.1093/cid/ciz075] [Citation(s) in RCA: 192] [Impact Index Per Article: 38.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Accepted: 01/22/2019] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND The severity of the 2017-2018 influenza season in the United States was high, with influenza A(H3N2) viruses predominating. Here, we report influenza vaccine effectiveness (VE) and estimate the number of vaccine-prevented influenza-associated illnesses, medical visits, hospitalizations, and deaths for the 2017-2018 influenza season. METHODS We used national age-specific estimates of 2017-2018 influenza vaccine coverage and disease burden. We estimated VE against medically attended reverse-transcription polymerase chain reaction-confirmed influenza virus infection in the ambulatory setting using a test-negative design. We used a compartmental model to estimate numbers of influenza-associated outcomes prevented by vaccination. RESULTS The VE against outpatient, medically attended, laboratory-confirmed influenza was 38% (95% confidence interval [CI], 31%-43%), including 22% (95% CI, 12%-31%) against influenza A(H3N2), 62% (95% CI, 50%-71%) against influenza A(H1N1)pdm09, and 50% (95% CI, 41%-57%) against influenza B. We estimated that influenza vaccination prevented 7.1 million (95% CrI, 5.4 million-9.3 million) illnesses, 3.7 million (95% CrI, 2.8 million-4.9 million) medical visits, 109 000 (95% CrI, 39 000-231 000) hospitalizations, and 8000 (95% credible interval [CrI], 1100-21 000) deaths. Vaccination prevented 10% of expected hospitalizations overall and 41% among young children (6 months-4 years). CONCLUSIONS Despite 38% VE, influenza vaccination reduced a substantial burden of influenza-associated illness, medical visits, hospitalizations, and deaths in the United States during the 2017-2018 season. Our results demonstrate the benefit of current influenza vaccination and the need for improved vaccines.
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Affiliation(s)
- Melissa A Rolfes
- Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Brendan Flannery
- Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Jessie R Chung
- Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Alissa O’Halloran
- Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Shikha Garg
- Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia
| | | | - Manjusha Gaglani
- Baylor Scott and White Health, Texas A&M University Health Science Center College of Medicine, Temple
| | | | | | - Arnold S Monto
- University of Michigan School of Public Health, Ann Arbor
| | - Nisha B Alden
- Colorado Department of Public Health and Environment, Denver
| | - Evan Anderson
- Georgia Emerging Infections Program, Atlanta VA Medical Center, Emory University, New York
| | - Nancy M Bennett
- University of Rochester School of Medicine and Dentistry, New York
| | | | - Seth Eckel
- Michigan Department of Health and Human Services, Lansing
| | | | | | | | | | - Nancy Spina
- New York State Emerging Infections Program, New York State Department of Health, Albany
| | | | | | | | | | - James A Singleton
- Immunization Services Division, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Manish Patel
- Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Carrie Reed
- Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Alicia M Fry
- Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia
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11
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Costantino V, Trent M, MacIntyre CR. Modelling of optimal timing for influenza vaccination as a function of intraseasonal waning of immunity and vaccine coverage. Vaccine 2019; 37:6768-6775. [PMID: 31521411 DOI: 10.1016/j.vaccine.2019.08.069] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2019] [Revised: 08/14/2019] [Accepted: 08/27/2019] [Indexed: 02/08/2023]
Abstract
The influenza season in Australia usually peaks in August. Vaccination is recommended beginning in March-April. Recent studies suggest that vaccine effectiveness may wane over a given influenza season, leading to reduced effectiveness at the peak of the season. We aimed to quantify how changes in timing of influenza vaccination and declining vaccine coverage could change the percentages of prevented cases. Results from a systematic review were used to inform calculation of a waning function over time from vaccination. Age specific notification data and vaccine effectiveness and coverage estimates from 2007 to 2016 (2009 influenza pandemic year excluded) were used to model a new notification series where vaccine effectiveness is shifted in time to account for delayed vaccination by month from March to August. A sensitivity analysis was done on possible vaccine coverage changes and considering time gap between vaccine uptake and recommendation. Delaying vaccination from March to end of May prevents more cases over a season, but the variation in cases prevented by month of vaccination is not large. If delaying vaccination results in missed or forgotten vaccination and decrease coverage, delaying vaccination could have a net negative impact. Furthermore, considering a time gap between recommendation and uptake, earlier recommendation is more effective in preventing cases. The results are sensitive to assumptions of intra-seasonal waning of effectiveness. More research is required on intra-seasonal vaccine effectiveness waning and the effect of delayed vaccination on overall uptake to inform any potential changes to current vaccine scheduling recommendations.
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Affiliation(s)
- Valentina Costantino
- Biosecurity Program, Kirby Institute, Faculty of Medicine, The University of New South Wales, Sydney, Australia.
| | - Mallory Trent
- Biosecurity Program, Kirby Institute, Faculty of Medicine, The University of New South Wales, Sydney, Australia.
| | - C Raina MacIntyre
- Biosecurity Program, Kirby Institute, Faculty of Medicine, The University of New South Wales, Sydney, Australia; College of Public Service and Community Solutions, Arizona State University, Arizona, USA.
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12
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Switzer C, Babiuk L, Loeb M. Determining optimal community protection strategies for the influenza vaccine. Expert Rev Vaccines 2019; 18:755-764. [PMID: 31288585 DOI: 10.1080/14760584.2019.1642110] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Introduction: Seasonal influenza poses a major risk to the health of the population. Optimal strategies for influenza vaccination can help to reduce this risk. Areas covered: Systematic evaluations of the burden of influenza are first reviewed. Key meta-analysis, randomized trials, and observational studies are critically reviewed to provide the best estimates of the efficacy of influenza vaccine. The concept of herd effect is first introduced and this is followed by the rationale and the evidence to support herd effect that can be provided with strategic use of influenza vaccination in populations. Challenges including the effect of repeated influenza vaccination and vaccine hesitancy are reviewed. The citations were selected by the authors based on PubMed searches of the literature. Expert opinion: Efforts to develop new vaccines, including a universal vaccine, offer the best prospects for improved herd effect. Increasing uptake in new populations can increase likelihood of a herd effect.
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Affiliation(s)
- Charlotte Switzer
- a Department of Health Research Evidence, and Impact, McMaster University , Hamilton , Ontario , Canada
| | - Lorne Babiuk
- b Department of Agricultural Life and Environmental Sciences, University of Alberta , Edmonton , Alberta , Canada
| | - Mark Loeb
- a Department of Health Research Evidence, and Impact, McMaster University , Hamilton , Ontario , Canada
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Chiu SS, Kwan MYW, Feng S, Wong JSC, Leung CW, Chan ELY, Chan KH, Ng TK, To WK, Cowling BJ, Peiris JSM. Influenza Vaccine Effectiveness Against Influenza A(H3N2) Hospitalizations in Children in Hong Kong in a Prolonged Season, 2016/2017. J Infect Dis 2019; 217:1365-1371. [PMID: 29346614 DOI: 10.1093/infdis/jiy027] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2017] [Accepted: 01/15/2018] [Indexed: 12/22/2022] Open
Abstract
Background Influenza A(H3N2) viruses circulated for 12 consecutive months in Hong Kong in 2016-2017, peaking in late June and July 2017. The objective of our study was to estimate the effectiveness of influenza vaccination in preventing hospitalizations in children in Hong Kong. Methods We conducted a test-negative study between 1 September 2016 and 31 August 2017, enrolling children 6 months to 17 years of age hospitalized for an acute respiratory infection. Influenza was diagnosed by PCR on nasopharyngeal aspirates. Results We enrolled 5514 children, including 3608 children 6 months to 2 years, 1600 children 3-5 years, and 1206 children 6-17 years of age. Influenza-associated hospitalizations occurred throughout the study year but time of vaccination of these children was also wide spread, from September 2016 to May 2017. Influenza vaccine effectiveness (VE) was 39.7% (95% confidence interval [CI], 14.7%-57.3%) against laboratory-confirmed influenza A(H3N2). In analyses stratified by time since vaccination, the VE against influenza A(H3N2) was 52.8% (95% CI, 17.1%-73.2%) within 3 months of vaccination, and 31.2% (95% CI, -6.6% to 55.6%) 4-6 months after vaccination. Conclusions Influenza vaccination was effective in preventing hospitalizations in children in Hong Kong.
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Affiliation(s)
- Susan S Chiu
- Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital and Li Ka Shing Faculty of Medicine, The University of Hong Kong
| | - Mike Y W Kwan
- Department of Paediatrics and Adolescent Medicine, Princess Margaret Hospital
| | - Shuo Feng
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health
| | - Joshua S C Wong
- Department of Paediatrics and Adolescent Medicine, Princess Margaret Hospital
| | - Chi-Wai Leung
- Department of Paediatrics and Adolescent Medicine, Princess Margaret Hospital
| | - Eunice L Y Chan
- Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital and Li Ka Shing Faculty of Medicine, The University of Hong Kong
| | - Kwok-Hung Chan
- Department of Microbiology, Li Ka Shing Faculty of Medicine, The University of Hong Kong
| | - Tak-Keung Ng
- Department of Pathology, Princess Margaret Hospital
| | | | - Benjamin J Cowling
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health
| | - J S Malik Peiris
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health.,Center of Influenza Research, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
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14
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Ainslie KEC, Haber M, Orenstein WA. Challenges in estimating influenza vaccine effectiveness. Expert Rev Vaccines 2019; 18:615-628. [PMID: 31116070 PMCID: PMC6594904 DOI: 10.1080/14760584.2019.1622419] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2019] [Accepted: 05/20/2019] [Indexed: 12/25/2022]
Abstract
Introduction: Influenza vaccination is regarded as the most effective way to prevent influenza infection. Due to the rapid genetic changes that influenza viruses undergo, seasonal influenza vaccines must be reformulated and re-administered annually necessitating the evaluation of influenza vaccine effectiveness (VE) each year. The estimation of influenza VE presents numerous challenges. Areas Covered: This review aims to identify, discuss, and, where possible, offer suggestions for dealing with the following challenges in estimating influenza VE: different outcomes of interest against which VE is estimated, study designs used to assess VE, sources of bias and confounding, repeat vaccination, waning immunity, population level effects of vaccination, and VE in at-risk populations. Expert Opinion: The estimation of influenza VE has improved with surveillance networks, better understanding of sources of bias and confounding, and the implementation of advanced statistical methods. Future research should focus on better estimates of the indirect effects of vaccination, the biological effects of vaccination, and how vaccines interact with the immune system. Specifically, little is known about how influenza vaccination impacts an individual's infectiousness, how vaccines wane over time, and the impact of repeated vaccination.
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Affiliation(s)
- Kylie E. C. Ainslie
- Research Associate in Influenza Disease Dynamics, MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, School of Public Health, Imperial College London, Norfolk Place, London W2 1PG, UK
| | - Michael Haber
- Professor, Department of Biostatistics and Bioinformatics, Rollins School of Public Health, Emory University, 1518 Clifton Rd NE, Atlanta, GA 30322, USA
| | - Walt A. Orenstein
- Professor, Division of Infectious Diseases, Department of Medicine, School of Medicine, Emory University, 1462 Clifton Rd NE, Atlanta, GA 30322, USA
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15
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Young B, Sadarangani S, Jiang L, Wilder-Smith A, Chen MIC. Duration of Influenza Vaccine Effectiveness: A Systematic Review, Meta-analysis, and Meta-regression of Test-Negative Design Case-Control Studies. J Infect Dis 2019; 217:731-741. [PMID: 29220496 DOI: 10.1093/infdis/jix632] [Citation(s) in RCA: 84] [Impact Index Per Article: 16.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2017] [Accepted: 12/01/2017] [Indexed: 02/03/2023] Open
Abstract
Background Whether influenza vaccination offers protection for the duration of an influenza season was called into question recently after analysis of data from test-negative design (TND) case-control studies. Method The published literature was systematically reviewed to identify TND studies that estimated the change in vaccine effectiveness (VE) with respect to time since vaccination. Results Fourteen studies were identified through the literature search as meeting eligibility criteria. Meta-analyses were performed to compare VE 15-90 days after vaccination to VE 91-180 days after vaccination. A significant decline in VE was observed for influenza virus subtype A/H3 (change in VE, -33; 95% confidence interval [CI], -57 to -12) and type B (change in VE, -19; 95% CI, -33 to -6). VE declined for influenza virus subtype A/H1, but this difference was not statistically significant (change in VE -8; 95% CI, -27 to 21). A multivariable mixed-effects meta-regression model indicated that the change VE was associated with the proportion of study participants who were cases and the proportion who were vaccinated controls (P < .05). This could reflect biological effects such as (1) mismatch between the vaccine received and the circulating strains (among cases), (2) herd immunity (among controls), or (3) the reduced power of individual TND studies in the later parts of an influenza outbreak. Conclusions Exploration of new influenza vaccination strategies must be a priority for influenza control, particularly in tropical countries with year-round influenza virus activity.
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Affiliation(s)
- Barnaby Young
- Institute of Infectious Diseases and Epidemiology, Tan Tock Seng Hospital, Singapore.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Sapna Sadarangani
- Institute of Infectious Diseases and Epidemiology, Tan Tock Seng Hospital, Singapore.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore
| | - Lili Jiang
- Saw Swee Hock School of Public Health, National University of Singapore, Singapore
| | - Annelies Wilder-Smith
- Institute of Infectious Diseases and Epidemiology, Tan Tock Seng Hospital, Singapore.,Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.,Institute of Public Health, University of Heidelberg, Germany
| | - Mark I-Cheng Chen
- Institute of Infectious Diseases and Epidemiology, Tan Tock Seng Hospital, Singapore.,Saw Swee Hock School of Public Health, National University of Singapore, Singapore
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16
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El Guerche-Séblain C, Caini S, Paget J, Vanhems P, Schellevis F. Epidemiology and timing of seasonal influenza epidemics in the Asia-Pacific region, 2010-2017: implications for influenza vaccination programs. BMC Public Health 2019; 19:331. [PMID: 30898100 PMCID: PMC6429768 DOI: 10.1186/s12889-019-6647-y] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Accepted: 03/12/2019] [Indexed: 12/17/2022] Open
Abstract
Background Description of the epidemiology of influenza is needed to inform influenza vaccination policy. Here we examined influenza virus circulation in countries in the Asia-Pacific region and compared the timing of seasonal epidemics with the timing of influenza vaccination. Methods Data were obtained from the World Health Organization (WHO) FluNet database for 2010–2017 for countries in the WHO Asia-Pacific region. Data from countries covering ≥5 consecutive seasons and ≥ 100 influenza positive cases per year were included. Median proportions of cases for each influenza virus type were calculated by country and season. The timing and amplitude of the epidemic peaks were determined by Fourier decomposition. Vaccination timing was considered appropriate for each country if it was recommended ≤4 months before the primary peak of influenza circulation. Results Seven hundred eleven thousand seven hundred thirty-four influenza cases were included from 19 countries. Peak circulation coincided with the winter seasons in most countries, although patterns were less clear in some countries in the inter-tropical area due to substantial secondary peaks. Influenza A/H3N2 dominated overall, but proportions of A and B strains varied by year and by country. Influenza B represented 31.4% of all cases. The WHO-recommended timing for influenza vaccination was appropriate in 12 countries. Vaccination timing recommendations were considered inappropriate in Laos, Cambodia, and Thailand, and were inconclusive for India, Sri Lanka, Singapore, and Vietnam due to unclear seasonality of influenza virus circulation. Conclusions Influenza virus circulation varied considerably across the Asia-Pacific region with an unusually high burden of influenza B. The recommended timing for vaccination was appropriate in most countries, except for several countries with unclear seasonality, mainly located in the inter-tropical area. Electronic supplementary material The online version of this article (10.1186/s12889-019-6647-y) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | - Saverio Caini
- Netherlands Institute for Health Services Research (NIVEL), Utrecht, The Netherlands
| | - John Paget
- Netherlands Institute for Health Services Research (NIVEL), Utrecht, The Netherlands
| | - Philippe Vanhems
- Epidemiology and International Health Team, Emergent Pathogens Laboratory, Fondation Mérieux, International Center for Research in Infectiology, National Institute of Health and Medical Research, U1111,National Center of Scientific Research, Mixed Scientific Unit 5308, École Nationale Supérieure de Lyon, Université Claude Bernard Lyon 1, Lyon, France
| | - François Schellevis
- Netherlands Institute for Health Services Research (NIVEL), Utrecht, The Netherlands.,Department of General Practice & Elderly Care Medicine, Amsterdam Public Health Research Institute, Amsterdam University Medical Centres, Amsterdam, The Netherlands
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17
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Feng S, Chiu SS, Chan ELY, Kwan MYW, Wong JSC, Leung CW, Chung Lau Y, Sullivan SG, Malik Peiris JS, Cowling BJ. Effectiveness of influenza vaccination on influenza-associated hospitalisations over time among children in Hong Kong: a test-negative case-control study. THE LANCET RESPIRATORY MEDICINE 2018; 6:925-934. [PMID: 30442587 DOI: 10.1016/s2213-2600(18)30419-3] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2018] [Revised: 10/02/2018] [Accepted: 10/04/2018] [Indexed: 12/13/2022]
Abstract
BACKGROUND The protection conferred by influenza vaccination is generally thought to last less than a year, necessitating annual revaccination. However, the speed with which influenza vaccine effectiveness might decline during a year is unknown, which is of particular importance for locations with year-round influenza activity. We aimed to assess how influenza vaccine effectiveness changes by time intervals between vaccination and admission to hospital, taking advantage of almost year-round circulation of influenza in Hong Kong. METHODS In this test-negative case-control study, we analysed vaccine effectiveness in children (aged 6 months to 17 years) who were admitted to hospital in Hong Kong over 5 consecutive years (2012-17). We included those who were admitted to general wards in four public hospitals in Hong Kong with a fever (≥38°C) and any respiratory symptom, such as runny nose, cough, or sore throat. We used direct immunofluorescence assay and reverse transcription PCR to detect influenza virus infection, and recorded children's influenza immunisation history. We compared characteristics of positive cases and negative controls and examined how vaccine effectiveness changed by time between vaccination and admission to hospital with regression analyses. FINDINGS Between Sept 1, 2012, and Aug 31, 2017, we enrolled 15 695 children hospitalised for respiratory infections, including 2500 (15·9%) who tested positive for influenza A or B and 13 195 (84·1%) who tested negative. 159 (6·4%) influenza-positive cases and 1445 (11·0%) influenza-negative cases had been vaccinated. Most vaccinations were done by December of each influenza vaccination season. Influenza-related admissions to hospital occurred year-round, with peaks in January through March in most years and a large summer peak in 2016; pooled vaccine effectiveness for children of all ages was 79% (95% CI 42-92) for September to December, 67% (57-74) for January to April, and 43% (25-57) for May to August. Vaccine effectiveness against influenza A or B was estimated as 79% (95% CI 64-88) within 0·5-2 months of vaccination, 60% (46-71) within >2-4 months, 57% (39-70) within >4-6 months, and 45% (22-61) within >6-9 months. In separate analyses by type and subtype, we estimated that vaccine effectiveness declined by 2-5 percentage points per month. INTERPRETATION Influenza vaccine effectiveness decreased during the 9 months after vaccination in children in Hong Kong. Our findings confirm the importance of annual vaccination in children. Influenza vaccines that provide broader and longer-lasting protection are needed to provide year-round protection in regions with irregular influenza seasonality or lengthy periods of influenza activity. FUNDING Health and Medical Research Fund, Hong Kong and the Research Grants Council, Hong Kong.
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Affiliation(s)
- Shuo Feng
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Susan S Chiu
- Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital and Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Eunice L Y Chan
- Department of Paediatrics and Adolescent Medicine, Queen Mary Hospital and Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Mike Y W Kwan
- Department of Paediatrics and Adolescent Medicine, Princess Margaret Hospital, Hong Kong Special Administrative Region, China
| | - Joshua S C Wong
- Department of Paediatrics and Adolescent Medicine, Princess Margaret Hospital, Hong Kong Special Administrative Region, China
| | - Chi-Wai Leung
- Department of Paediatrics and Adolescent Medicine, Princess Margaret Hospital, Hong Kong Special Administrative Region, China
| | - Yiu Chung Lau
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Sheena G Sullivan
- WHO Collaborating Center for Reference and Research on Influenza at the Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia; Department of Epidemiology, Fielding School of Public Health, University of California, Los Angeles, Los Angeles, CA, USA; Centre for Epidemiology and Biostatistics, School of Population and Global Health, University of Melbourne, Melbourne, VIC, Australia
| | - J S Malik Peiris
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Benjamin J Cowling
- WHO Collaborating Centre for Infectious Disease Epidemiology and Control, School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China.
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18
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Cheng HY, Chen WC, Chou YJ, Huang ASE, Huang WT. Containing influenza outbreaks with antiviral use in long-term care facilities in Taiwan, 2008-2014. Influenza Other Respir Viruses 2018; 12:287-292. [PMID: 29341490 PMCID: PMC5820419 DOI: 10.1111/irv.12536] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 12/17/2017] [Indexed: 11/28/2022] Open
Abstract
Backgrounds Influenza can spread rapidly in long‐term care facilities (LTCFs), and residents are usually at higher risk for influenza infections. Objective Our study aimed to evaluate the effectiveness of antiviral interventions on outbreak control. Methods Taiwan Centers for Disease Control used a syndromic surveillance system to monitor outbreaks in LTCFs. Local public health authorities verified those outbreaks and logged reports to the Epidemic Investigation Report Files Management System (EIRFMS). We conducted a retrospective cohort study by reviewing EIRFMS reports of influenza outbreaks in LTCFs during 2008‐2014. An influenza outbreak was defined as 3 or more cases of influenza‐like illness occurring within a 48‐hours period with ≥1 case of real‐time RT‐PCR‐confirmed influenza in the same LTCF. Antiviral interventions included providing antiviral treatment for patients and antiviral prophylaxis for contacts during outbreaks. Results Of 102 influenza outbreaks, median days from onset of the first patient to outbreak notification was 4 (range 0‐22). Median attack rate was 24% (range 2.2%‐100%). Median influenza vaccination coverage among residents was 81% (range 0%‐100%); 43% occurred during the summer months. Even though antiviral treatment was provided in 87% of the outbreaks, antiviral prophylaxis was implemented in only 40%. Starting antiviral treatment within 2 days of outbreak onset was associated with keeping attack rates at <25% (OR 0.29, 95% CI: 0.12‐0.71). Conclusions Early initiation of antiviral treatment may reduce the magnitude of influenza outbreaks. Clinicians should identify patients with influenza and start antiviral use early to prevent large outbreaks in LTCFs.
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Affiliation(s)
- Hao-Yuan Cheng
- Epidemic Intelligence Center, Taiwan Centers for Disease Control, Taipei, Taiwan
| | - Wan-Chin Chen
- Office of Preventive Medicine, Taiwan Centers for Disease Control, Taipei, Taiwan
| | - Yu-Ju Chou
- Office of Preventive Medicine, Taiwan Centers for Disease Control, Taipei, Taiwan
| | - Angela Song-En Huang
- Division of Acute Infectious Diseases, Taiwan Centers for Disease Control, Taipei, Taiwan
| | - Wan-Ting Huang
- Office of Preventive Medicine, Taiwan Centers for Disease Control, Taipei, Taiwan
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19
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Tang JW, Mutuyimana J, Teo KW, Lea S, Galiano M, Lackenby A, Donaghy B, Blount J, Ellis J, Range S. Early seasonal influenza vaccination and delayed influenza peaks – A possible cause of end-of-season outbreaks. J Infect 2018; 76:96-98. [PMID: 28804025 DOI: 10.1016/j.jinf.2017.08.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2017] [Accepted: 08/04/2017] [Indexed: 10/19/2022]
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20
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Influenza vaccination status and outcomes among influenza-associated hospitalizations in Columbus, Ohio (2012-2015). Epidemiol Infect 2017; 145:3284-3293. [PMID: 29032772 DOI: 10.1017/s0950268817002163] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Prior studies suggest that the influenza vaccine is protective against some outcomes in hospitalized patients infected with influenza despite vaccination. We utilized surveillance data from Columbus, Ohio to investigate this association over multiple influenza seasons and age groups. Data on laboratory-confirmed influenza-associated hospitalizations were collected as a part of the Influenza Hospitalization Surveillance Project for the 2012-2013, 2013-2014, and 2014-2015 influenza seasons. The association between influenza vaccination status was examined in relation to the outcomes of severe influenza and diagnosis of pneumonia among patients receiving antiviral treatment. Data were analyzed using multivariable logistic regression. We observed no overall association between influenza vaccination status and severe influenza among hospitalized patients. During the 2013-2014 season, those who were vaccinated were 41% less likely to be diagnosed with pneumonia compared with those who were unvaccinated (OR = 0·59 95% CI 0·41-0·86). The influenza vaccine may provide a secondary preventive function against pneumonia among influenza cases requiring hospitalization. However, a protective effect was only observed in 2013-2014, an influenza H1N1 dominant year. Differences in circulating influenza virus strains and vaccine matching to the circulating strains during influenza seasons may impact this association.
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21
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Puig-Barberà J, Mira-Iglesias A, Tortajada-Girbés M, López-Labrador FX, Librero-López J, Díez-Domingo J, Carballido-Fernández M, Carratalá-Munuera C, Correcher-Medina P, Gil-Guillén V, Limón-Ramírez R, Mollar-Maseres J, Otero-Reigada MC, Schwarz H. Waning protection of influenza vaccination during four influenza seasons, 2011/2012 to 2014/2015. Vaccine 2017; 35:5799-5807. [PMID: 28941618 DOI: 10.1016/j.vaccine.2017.09.035] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 07/06/2017] [Accepted: 09/12/2017] [Indexed: 01/07/2023]
Abstract
BACKGROUND Concerns have been raised about intraseasonal waning of the protection conferred by influenza vaccination. METHODS During four influenza seasons, we consecutively recruited individuals aged 18years or older who had received seasonal influenza vaccine and were subsequently admitted to the hospital for influenza infection, asassessed by reverse transcription polymerase chain reaction. We estimated the adjusted odds ratio (aOR) of influenza infection by date of vaccination, defined by tertiles, as early, intermediate or late vaccination. We used a test-negative approach with early vaccination as reference to estimate the aOR of hospital admission with influenza among late vaccinees. We conducted sensitivity analyses by means of conditional logistic regression, Cox proportional hazards regression, and using days between vaccination and hospital admission rather than vaccination date. RESULTS Among 3615 admitted vaccinees, 822 (23%) were positive for influenza. We observed a lower risk of influenza among late vaccinees during the 2011/2012 and 2014/2015A(H3N2)-dominant seasons: aOR=0.68 (95% CI: 0.47-1.00) and 0.69 (95% CI: 0.50-0.95). We found no differences in the risk of admission with influenza among late versus early vaccinees in the 2012/2013A(H1N1)pdm09-dominant or 2013/2014B/Yamagata lineage-dominant seasons: aOR=1.18 (95% CI: 0.58-2.41) and 0.98 (95% CI: 0.56-1.72). When we restricted our analysis to individuals aged 65years or older, we found a statistically significant lower risk of admission with influenza among late vaccinees during the 2011/2012 and 2014/2015A(H3N2)-dominant seasons: aOR=0.61 (95% CI: 0.41-0.91) and 0.69 (95% CI: 0.49-0.96). We observed 39% (95% CI: 9-59%) and 31% (95% CI: 5-50%) waning of vaccine effectiveness among participants aged 65years or older during the two A(H3N2)-dominant seasons. Similar results were obtained in the sensitivity analyses. CONCLUSION Waning of vaccine protection was observed among individuals aged 65years old or over in two A(H3N2)-dominant influenza seasons.
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Affiliation(s)
- J Puig-Barberà
- FISABIO-Salud Pública, 46020 Valencia, Spain; Centro de Salud Pública de Castellón, 12003 Castellón, Spain.
| | | | | | - F X López-Labrador
- FISABIO-Salud Pública, 46020 Valencia, Spain; CIBERESP, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | - J Librero-López
- Navarrabiomed - Fundación Miguel Servet, 31008 Pamplona, Spain; REDISSEC, Instituto de Salud Carlos III, 28029 Madrid, Spain
| | | | - M Carballido-Fernández
- Universidad CEU-UCH, 12006 Castellón, Spain; Hospital General Universitario de Castellón, 12004 Castellón, Spain
| | - C Carratalá-Munuera
- Universidad Miguel Hernández, 03202 Elche, Spain; Hospital San Juan de Alicante, 03550 Alicante, Spain
| | | | | | | | | | | | - H Schwarz
- Hospital General de Alicante, 03010 Alicante, Spain
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Kissling E, Nunes B, Robertson C, Valenciano M, Reuss A, Larrauri A, Cohen JM, Oroszi B, Rizzo C, Machado A, Pitigoi D, Domegan L, Paradowska-Stankiewicz I, Buchholz U, Gherasim A, Daviaud I, Horváth JK, Bella A, Lupulescu E, O Donnell J, Korczyńska M, Moren A. I-MOVE multicentre case-control study 2010/11 to 2014/15: Is there within-season waning of influenza type/subtype vaccine effectiveness with increasing time since vaccination? ACTA ACUST UNITED AC 2017; 21:30201. [PMID: 27124420 DOI: 10.2807/1560-7917.es.2016.21.16.30201] [Citation(s) in RCA: 72] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 02/10/2016] [Indexed: 11/20/2022]
Abstract
Since the 2008/9 influenza season, the I-MOVE multicentre case-control study measures influenza vaccine effectiveness (VE) against medically-attended influenza-like-illness (ILI) laboratory confirmed as influenza. In 2011/12, European studies reported a decline in VE against influenza A(H3N2) within the season. Using combined I-MOVE data from 2010/11 to 2014/15 we studied the effects of time since vaccination on influenza type/subtype-specific VE. We modelled influenza type/subtype-specific VE by time since vaccination using a restricted cubic spline, controlling for potential confounders (age, sex, time of onset, chronic conditions). Over 10,000 ILI cases were included in each analysis of influenza A(H3N2), A(H1N1)pdm09 and B; with 4,759, 3,152 and 3,617 influenza positive cases respectively. VE against influenza A(H3N2) reached 50.6% (95% CI: 30.0-65.1) 38 days after vaccination, declined to 0% (95% CI: -18.1-15.2) from 111 days onwards. At day 54 VE against influenza A(H1N1)pdm09 reached 55.3% (95% CI: 37.9-67.9) and remained between this value and 50.3% (95% CI: 34.8-62.1) until season end. VE against influenza B declined from 70.7% (95% CI: 51.3-82.4) 44 days after vaccination to 21.4% (95% CI: -57.4-60.8) at season end. To assess if vaccination campaign strategies need revising more evidence on VE by time since vaccination is urgently needed.
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Young B, Sadarangani S, Yew HS, Yung CF, Leo YS, Chen MIC, Wilder-Smith A. The immune response to 6-monthly versus annual standard dose inactivated trivalent influenza vaccination in older people: study protocol for a randomised clinical trial. Trials 2017; 18:67. [PMID: 28183326 PMCID: PMC5301431 DOI: 10.1186/s13063-017-1808-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2016] [Accepted: 01/20/2017] [Indexed: 11/10/2022] Open
Abstract
Background The seasonal influenza vaccine is less effective in older people and a single dose is unlikely to provide the year-round protection necessary for tropical climates which have year-round influenza virus activity. This study aims to assess the effect of a trivalent inactivated influenza vaccine (IIV3) booster at 180 days on haemagglutination-inhibition (HI) antibody titres for each of the influenza strains present in the administered vaccine in older people aged 65 years or above in Singapore. Methods/design This is a single-centre, randomised, observer-blind, active-comparator controlled, parallel-group, phase IV trial in 200 adults aged 65 years or older. Study participants will be assigned to one of two groups in a 1:1 ratio and followed for 1 year, with five scheduled visits. The control group will receive IIV3 at day 1, and an active comparator (Tetanus-diphtheria-pertussis vaccine) at day 180. Participants in the experimental group will receive IIV3 containing the same strains at day 1 and day 180. Endpoints are immunological, and include measures of HI titres, microneutralisation titres (MN) and cell-mediated immunity from first vaccination up to day 360. Discussion If superiority of 6-monthly influenza vaccination is demonstrated, this study could form the basis for a larger clinical trial with influenza infection as the primary endpoint. Trial registration ClinicalTrials.gov, ID: NCT02655874. Registered on 12 January 2016. Electronic supplementary material The online version of this article (doi:10.1186/s13063-017-1808-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Barnaby Young
- Institute of Infectious Diseases and Epidemiology (IIDE), Tan Tock Seng Hospital, 11 Jalan, Singapore, 308433, Singapore. .,Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore, 308232, Singapore.
| | - Sapna Sadarangani
- Institute of Infectious Diseases and Epidemiology (IIDE), Tan Tock Seng Hospital, 11 Jalan, Singapore, 308433, Singapore.,Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore, 308232, Singapore
| | - Haur Sen Yew
- Institute of Infectious Diseases and Epidemiology (IIDE), Tan Tock Seng Hospital, 11 Jalan, Singapore, 308433, Singapore
| | - Chee Fu Yung
- Infectious Diseases Service, KK Women's and Children's Hospital, 100 Bukit Timah Road, Singapore, 229899, Singapore
| | - Yee Sin Leo
- Institute of Infectious Diseases and Epidemiology (IIDE), Tan Tock Seng Hospital, 11 Jalan, Singapore, 308433, Singapore.,Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore, 308232, Singapore.,Saw Swee Hock School of Public Health, Thair Foundation Building, National University of Singapore, 12 Science Drive 2, Singapore, 117549, Singapore
| | - Mark I-Cheng Chen
- Institute of Infectious Diseases and Epidemiology (IIDE), Tan Tock Seng Hospital, 11 Jalan, Singapore, 308433, Singapore.,Saw Swee Hock School of Public Health, Thair Foundation Building, National University of Singapore, 12 Science Drive 2, Singapore, 117549, Singapore
| | - Annelies Wilder-Smith
- Institute of Infectious Diseases and Epidemiology (IIDE), Tan Tock Seng Hospital, 11 Jalan, Singapore, 308433, Singapore.,Lee Kong Chian School of Medicine, Nanyang Technological University, 11 Mandalay Road, Singapore, 308232, Singapore
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Young B, Zhao X, Cook AR, Parry CM, Wilder-Smith A, I-Cheng MC. Do antibody responses to the influenza vaccine persist year-round in the elderly? A systematic review and meta-analysis. Vaccine 2016; 35:212-221. [PMID: 27939013 DOI: 10.1016/j.vaccine.2016.11.013] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2016] [Revised: 09/19/2016] [Accepted: 11/04/2016] [Indexed: 12/20/2022]
Abstract
INTRODUCTION The influenza vaccine is less immunogenic in older than younger adults, and the duration of protection is unclear. Determining if protection persists beyond a typical seasonal epidemic is important for climates where influenza virus activity is year-round. METHODS A systematic review protocol was developed and registered with PROSPERO [CRD42015023847]. Electronic databases were searched systematically for studies reporting haemagglutination-inhibition (HI) titres 180-360days following vaccination with inactivated trivalent seasonal influenza vaccine, in adults aged ⩾65years. Geometric mean titre (GMT) and seroprotection (HI titre ⩾1:40) at each time point was extracted. A Bayesian model was developed of titre trajectories from pre-vaccination to Day 360. In the meta-analysis, studies were aggregated using a random-effects model to compare pre-vaccination with post-vaccination HI titres at Day 21-42 ('seroconversion'), Day 180 and Day 360. Potential sources of bias were systematically assessed, and heterogeneity explored. RESULTS 2864 articles were identified in the literature search, of which nineteen met study inclusion/exclusion criteria. Sixteen studies contained analysable data from 2565 subjects. In the Bayesian model, the proportion of subjects seroprotected increased from 41-51% pre-vaccination to 75-78% at seroconversion. Seroprotection subsequently fell below 60% for all serotypes by Day 360: A/H1 42% (95% CI 38-46), A/H3 59% (54-63), B 47% (42-52). The Bayesian model of GMT trajectories revealed a similar pattern. By Day 360, titres were similar to pre-vaccination levels. In the meta-analysis, no significant difference in proportion of subjects seroprotected, 0 (-0.11, 0.11) or in log2GMT 0.30 (-0.02, 0.63) was identified by Day 360 compared with pre-vaccination. The quality of this evidence was limited to moderate on account of significant participant dropout. CONCLUSIONS The review found consistent evidence that HI antibody responses following influenza vaccination do not reliably persist year-round in older adults. Alternative vaccination strategies could provide clinical benefits in regions where year-round protection is important.
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Affiliation(s)
- Barnaby Young
- Institute of Infectious Diseases and Epidemiology, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, 308433 Singapore, Singapore.
| | - Xiahong Zhao
- Saw Swee Hock School of Public Health, Tahir Foundation Building, National University of Singapore, 12 Science Drive 2, #09-01, 117549 Singapore, Singapore
| | - Alex R Cook
- Saw Swee Hock School of Public Health, Tahir Foundation Building, National University of Singapore, 12 Science Drive 2, #09-01, 117549 Singapore, Singapore; Yale-NUS College, National University of Singapore, 16 College Avenue West #01-220, 138527 Singapore, Singapore
| | - Christopher M Parry
- School of Tropical Medicine and Global Health, Nagasaki University Institute of Tropical Medicine, 1-12-4 Sakamoto, Nagasaki 852-8523, Japan; London School of Hygiene and Tropical Medicine, Keppel Street, London WC1E 7HT, UK
| | - Annelies Wilder-Smith
- Institute of Infectious Diseases and Epidemiology, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, 308433 Singapore, Singapore; Lee Kong Chian School of Medicine, 11 Mandalay Road, 308232 Singapore, Singapore
| | - Mark Chen I-Cheng
- Institute of Infectious Diseases and Epidemiology, Tan Tock Seng Hospital, 11 Jalan Tan Tock Seng, 308433 Singapore, Singapore; Saw Swee Hock School of Public Health, Tahir Foundation Building, National University of Singapore, 12 Science Drive 2, #09-01, 117549 Singapore, Singapore
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Variable influenza vaccine effectiveness by subtype: a systematic review and meta-analysis of test-negative design studies. THE LANCET. INFECTIOUS DISEASES 2016; 16:942-51. [DOI: 10.1016/s1473-3099(16)00129-8] [Citation(s) in RCA: 420] [Impact Index Per Article: 52.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/05/2015] [Revised: 02/20/2016] [Accepted: 02/23/2016] [Indexed: 01/04/2023]
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Kelly HA, Lane C, Cheng AC. Influenza vaccine effectiveness in general practice and in hospital patients in Victoria, 2011-2013. Med J Aust 2016; 204:76. [PMID: 26821109 DOI: 10.5694/mja15.01017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2015] [Accepted: 11/13/2015] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To compare influenza vaccine effectiveness in the general practice and hospital settings. DESIGN Analysis of annual case test-negative studies. SETTING Victorian sentinel hospitals and general practices, 2011-2013. PARTICIPANTS Patients presenting to general practitioners, or those admitted to hospital with an influenza-like illness who were tested for influenza using a polymerase chain reaction assay. Cases were patients with a positive test result for influenza; non-cases (controls) had a negative test result. MAIN OUTCOME MEASURES Vaccine effectiveness against laboratory-confirmed influenza. RESULTS Hospitalised patients were on average older and reported a higher proportion of comorbidities than general practice patients. The pooled estimate of influenza vaccine effectiveness against laboratory-confirmed infection for the 3 years was 50% (95% CI, 26%-66%) for general practice patients and 39% (95% CI, 28%-47%) for patients admitted to hospital. CONCLUSIONS Influenza vaccines appeared to be similarly modestly effective in the general practice and hospital settings. Influenza vaccination appears to prevent hospital admission by preventing symptomatic infection rather than by attenuating the severity of illness.
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Affiliation(s)
- Heath A Kelly
- Victorian Infectious Diseases Reference Laboratory, Melbourne, VIC
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Radin JM, Hawksworth AW, Myers CA, Ricketts MN, Hansen EA, Brice GT. Influenza vaccine effectiveness: Maintained protection throughout the duration of influenza seasons 2010-2011 through 2013-2014. Vaccine 2016; 34:3907-12. [PMID: 27265447 DOI: 10.1016/j.vaccine.2016.05.034] [Citation(s) in RCA: 35] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2015] [Revised: 04/26/2016] [Accepted: 05/12/2016] [Indexed: 11/29/2022]
Abstract
BACKGROUND Factors, such as age, comorbidities, vaccine type, herd immunity, previous influenza exposure, and antigenic shift may impact the immune response to the influenza vaccine, protection against circulating strains, and antibody waning. Evaluating vaccine effectiveness (VE) is important for informing timing of vaccine administration and evaluating overall vaccine benefit. METHODS VE was assessed using febrile respiratory illness surveillance among Department of Defense non-active duty beneficiaries from influenza seasons 2010-2011 through 2013-2014. Respiratory specimens were taken from participants meeting the case definition and tested by polymerase chain reaction for influenza. VE was calculated using logistic regression and by taking 1 minus the odds ratio of being vaccinated in the laboratory confirmed positive influenza cases versus laboratory confirmed negative controls. RESULTS This study included 1486 participants. We found an overall adjusted VE that provided significant and fairly consistent protection ranging from 54% to 67% during 0-180days postvaccination. This VE dropped to -11% (95% confidence interval: -102% to 39%) during 181-365days. CONCLUSIONS Our study found moderate VE up to 6months postvaccination. Since the influenza season starts at different times each year, optimal timing is difficult to predict. Consequently, early influenza vaccination may still offer the best overall protection.
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Affiliation(s)
- Jennifer M Radin
- Department of Operational Infectious Diseases, Naval Health Research Center, San Diego, CA 92106, USA.
| | - Anthony W Hawksworth
- Department of Operational Infectious Diseases, Naval Health Research Center, San Diego, CA 92106, USA
| | - Christopher A Myers
- Department of Operational Infectious Diseases, Naval Health Research Center, San Diego, CA 92106, USA
| | - Michelle N Ricketts
- Department of Operational Infectious Diseases, Naval Health Research Center, San Diego, CA 92106, USA
| | - Erin A Hansen
- Department of Operational Infectious Diseases, Naval Health Research Center, San Diego, CA 92106, USA
| | - Gary T Brice
- Department of Operational Infectious Diseases, Naval Health Research Center, San Diego, CA 92106, USA
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Kittikraisak W, Chittaganpitch M, Gregory CJ, Laosiritaworn Y, Thantithaveewat T, Dawood FS, Lindblade KA. Assessment of potential public health impact of a quadrivalent inactivated influenza vaccine in Thailand. Influenza Other Respir Viruses 2016; 10:211-9. [PMID: 26588892 PMCID: PMC4814859 DOI: 10.1111/irv.12361] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/10/2015] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Each year, an influenza B strain representing only one influenza B lineage is included in the trivalent inactivated influenza vaccine (IIV3); a mismatch between the selected lineage and circulating viruses can result in suboptimal vaccine effectiveness. We modeled the added potential public health impact of a quadrivalent inactivated influenza vaccine (IIV4) that includes strains from both influenza B lineages compared to IIV3 on influenza-associated morbidity and mortality in Thailand. METHODS Using data on the incidence of influenza-associated hospitalizations and deaths, vaccine effectiveness, and vaccine coverage from the 2007-2012 influenza seasons in Thailand, we estimated rates of influenza-associated outcomes that might be averted using IIV4 instead of IIV3. We then applied these rates to national population estimates to calculate averted illnesses, hospitalizations, and deaths for each season. We assumed that the influenza B lineage included in IIV3 would provide a relative vaccine effectiveness of 75% against the other B lineage. RESULTS Compared to use of IIV3, use of IIV4 might have led to an additional reduction ranging from 0·4 to 14·3 influenza-associated illnesses per 100 000 population/year, <0·1 to 0·5 hospitalizations per 100 000/year, and <0·1 to 0·4 deaths per 1000/year. Based on extrapolation to national population estimates, replacement of IIV3 with IIV4 might have averted an additional 267-9784 influenza-associated illnesses, 9-320 hospitalizations, and 0-3 deaths. CONCLUSION Compared to use of IIV3, IIV4 has the potential to further reduce the burden of influenza-associated morbidity and mortality in Thailand.
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Affiliation(s)
- Wanitchaya Kittikraisak
- Influenza ProgramThailand Ministry of Public Health – U.S. Centers for Disease Control and Prevention CollaborationNonthaburiThailand
| | | | - Christopher J. Gregory
- International Emerging Infections ProgramThailand Ministry of Public Health – U.S. Centers for Disease Control and Prevention CollaborationNonthaburiThailand
- Division of Global Health ProtectionU.S. Centers for Disease Control and PreventionAtlantaGAUSA
| | | | | | - Fatimah S. Dawood
- Influenza DivisionU.S. Centers for Disease Control and PreventionAtlantaGAUSA
| | - Kim A. Lindblade
- Influenza ProgramThailand Ministry of Public Health – U.S. Centers for Disease Control and Prevention CollaborationNonthaburiThailand
- Influenza DivisionU.S. Centers for Disease Control and PreventionAtlantaGAUSA
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Abstract
Data were pooled from three Australian sentinel general practice influenza surveillance networks to estimate Australia-wide influenza vaccine coverage and effectiveness against community presentations for laboratory-confirmed influenza for the 2012, 2013 and 2014 seasons. Patients presenting with influenza-like illness at participating GP practices were swabbed and tested for influenza. The vaccination odds of patients testing positive were compared with patients testing negative to estimate influenza vaccine effectiveness (VE) by logistic regression, adjusting for age group, week of presentation and network. Pooling of data across Australia increased the sample size for estimation from a minimum of 684 to 3,683 in 2012, from 314 to 2,042 in 2013 and from 497 to 3,074 in 2014. Overall VE was 38% [95% confidence interval (CI) 24-49] in 2012, 60% (95% CI 45-70) in 2013 and 44% (95% CI 31-55) in 2014. For A(H1N1)pdm09 VE was 54% (95% CI-28 to 83) in 2012, 59% (95% CI 33-74) in 2013 and 55% (95% CI 39-67) in 2014. For A(H3N2), VE was 30% (95% CI 14-44) in 2012, 67% (95% CI 39-82) in 2013 and 26% (95% CI 1-45) in 2014. For influenza B, VE was stable across years at 56% (95% CI 37-70) in 2012, 57% (95% CI 30-73) in 2013 and 54% (95% CI 21-73) in 2014. Overall VE against influenza was low in 2012 and 2014 when A(H3N2) was the dominant strain and the vaccine was poorly matched. In contrast, overall VE was higher in 2013 when A(H1N1)pdm09 dominated and the vaccine was a better match. Pooling data can increase the sample available and enable more precise subtype- and age group-specific estimates, but limitations remain.
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Neuzil KM. The Art and Science of Delivering Influenza Vaccines. J Infect Dis 2016; 214:1129-31. [DOI: 10.1093/infdis/jiw106] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2016] [Accepted: 03/08/2016] [Indexed: 11/13/2022] Open
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Petrie JG, Ohmit SE, Truscon R, Johnson E, Braun TM, Levine MZ, Eichelberger MC, Monto AS. Modest Waning of Influenza Vaccine Efficacy and Antibody Titers During the 2007-2008 Influenza Season. J Infect Dis 2016; 214:1142-9. [PMID: 27095420 DOI: 10.1093/infdis/jiw105] [Citation(s) in RCA: 44] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2015] [Accepted: 01/26/2016] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Antibody titers decrease with time following influenza vaccination, raising concerns that vaccine efficacy might wane. However, the relationship between time since vaccination and protection is unclear. METHODS Time-varying vaccine efficacy (VE[t]) was examined in healthy adult participants (age range, 18-49 years) in a placebo-controlled trial of inactivated influenza vaccine (IIV) and live-attenuated influenza vaccine (LAIV) performed during the 2007-2008 influenza season. Symptomatic respiratory illnesses were laboratory-confirmed as influenza. VE(t) was estimated by fitting a smooth function based on residuals from Cox proportional hazards models. Subjects had blood samples collected immediately prior to vaccination, 30 days after vaccination, and at the end of the influenza season for testing by hemagglutination inhibition and neuraminidase inhibition assays. RESULTS Overall efficacy was 70% (95% confidence interval [CI], 50%-82%) for IIV and 38% (95% CI, 5%-59%) for LAIV. Statistically significant waning was detected for IIV (P = .03) but not LAIV (P = .37); however, IIV remained significantly efficacious until data became sparse at the end of the season. Similarly, antibody titers against influenza virus hemagglutinin and neuraminidase significantly decreased over the season among IIV recipients. CONCLUSIONS Both vaccines were efficacious but LAIV less so. IIV efficacy decreased slowly over time, but the vaccine remained significantly efficacious for the majority of the season.
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Affiliation(s)
| | | | | | | | - Thomas M Braun
- Department of Biostatistics, University of Michigan School of Public Health, Ann Arbor
| | - Min Z Levine
- Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia
| | - Maryna C Eichelberger
- Division of Viral Products, Center for Biologics Evaluation and Research, Food and Drug Administration, Silver Spring, Maryland
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Lane CR, Carville KS, Pierse N, Kelly HA. Seasonal influenza vaccine effectiveness estimates: Development of a parsimonious case test negative model using a causal approach. Vaccine 2016; 34:1070-6. [PMID: 26795366 DOI: 10.1016/j.vaccine.2016.01.002] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2015] [Revised: 11/30/2015] [Accepted: 01/04/2016] [Indexed: 11/17/2022]
Abstract
BACKGROUND Influenza vaccine effectiveness (VE) is increasingly estimated using the case-test negative study design. Cases have a symptom complex consistent with influenza and test positive for influenza, while non-cases have the same symptom complex but test negative. We aimed to determine a parsimonious logistic regression model for this study design when applied to patients in the community. METHODS To determine the minimum covariate set required, we used a previously published systematic review to find covariates and restriction criteria commonly included in case-test negative logistic regression models. Covariates were assessed for inclusion using a directed acyclic graph. We used data from the Victorian Influenza Sentinel Practice Network from 2007 to 2013, excluding the pandemic year of 2009, to test the model. VE was estimated as (1-adjusted OR) * 100%. Changes in model fit from addition of specified covariates were examined. Restriction criteria were examined using change in VE estimate. VE was estimated for each year, all years aggregated, and for influenza type and sub-type. RESULTS Using publicly available software, the directed acyclic graph indicated that covariates specifying age, time within the influenza season, immunocompromising comorbid conditions and year or study site, where applicable, were required for closure. The inclusion of sex was not required. Inclusions and exclusions were validated when testing the variables (when collected) with our data. Restriction by time between onset and swab was supported by the data. VE for all years aggregated was estimated as 53% (95%CI 38, 64). VE was estimated as 42% (95%CI 19, 59) for H3N2, 75% (95%CI 51, 88) for H1N1pdm09 and 63% (95%CI 38, 79) for influenza B. CONCLUSION Theoretical covariates specified by the directed acyclic graph were validated when tested against surveillance data. A parsimonious model using the case test negative design allows regular estimates of VE and aggregated estimates by year.
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Affiliation(s)
- C R Lane
- Epidemiology Unit, Victorian Infectious Disease Reference Laboratory at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia; National Centre for Epidemiology and Population Health, Australian National University, Canberra, Australia.
| | - K S Carville
- National Centre for Epidemiology and Population Health, Australian National University, Canberra, Australia.
| | - N Pierse
- University of Otago, Wellington, New Zealand.
| | - H A Kelly
- Epidemiology Unit, Victorian Infectious Disease Reference Laboratory at the Peter Doherty Institute for Infection and Immunity, Melbourne, Australia; National Centre for Epidemiology and Population Health, Australian National University, Canberra, Australia.
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Incidence of medically attended influenza infection and cases averted by vaccination, 2011/2012 and 2012/2013 influenza seasons. Vaccine 2015; 33:5181-7. [PMID: 26271827 DOI: 10.1016/j.vaccine.2015.07.098] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2014] [Revised: 07/28/2015] [Accepted: 07/29/2015] [Indexed: 11/21/2022]
Abstract
BACKGROUND We estimated the burden of outpatient influenza and cases prevented by vaccination during the 2011/2012 and 2012/2013 influenza seasons using data from the United States Influenza Vaccine Effectiveness (US Flu VE) Network. METHODS We defined source populations of persons who could seek care for acute respiratory illness (ARI) at each of the five US Flu VE Network sites. We identified all members of the source population who were tested for influenza during US Flu VE influenza surveillance. Each influenza-positive subject received a sampling weight based on the proportion of source population members who were tested for influenza, stratified by site, age, and other factors. We used the sampling weights to estimate the cumulative incidence of medically attended influenza in the source populations. We estimated cases averted by vaccination using estimates of cumulative incidence, vaccine coverage, and vaccine effectiveness. RESULTS Cumulative incidence of medically attended influenza ranged from 0.8% to 2.8% across sites during 2011/2012 and from 2.6% to 6.5% during the 2012/2013 season. Stratified by age, incidence ranged from 1.2% among adults 50 years of age and older in 2011/2012 to 10.9% among children 6 months to 8 years of age in 2012/2013. Cases averted by vaccination ranged from 4 to 41 per 1000 vaccinees, depending on the study site and year. CONCLUSIONS The incidence of medically attended influenza varies greatly by year and even by geographic region within the same year. The number of cases averted by vaccination varies greatly based on overall incidence and on vaccine coverage.
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Lee HK, Tang JWT, Loh TP, Oon LLE, Koay ESC. Predicting clinical severity based on substitutions near epitope A of influenza A/H3N2. INFECTION GENETICS AND EVOLUTION 2015; 34:292-7. [PMID: 26118307 DOI: 10.1016/j.meegid.2015.06.025] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Revised: 06/15/2015] [Accepted: 06/25/2015] [Indexed: 01/03/2023]
Abstract
Epitopes are the main targets for specific antibodies in the host defense systems. Recent studies have shown that amino acid (aa) substitutions located within the influenza A/H3N2 hemagglutinin 1 (HA1) epitopes A-E, particularly in A and B, result in antigenic drift. Viruses with such drift mutations may have resulted in more severe influenza-related illness during influenza epidemics between late 2012 and early 2015. We sought to quantify vaccine mismatches in epitopes A-E of the HA1 protein, and correlate these with the severity of the patient's illness. The influenza A/H3N2 clinical samples were collected between April 2009 and November 2013 (n=206). Patients were clinically stratified into groups with mild, moderate, and severe influenza-like illness (ILI). The impact of the number of aa mismatches in each of epitopes A-E, gender, age groups (⩽18, 19-64, ⩾65 years), and comorbidities on the likelihood that patients would suffer moderate and/or severe ILI due to influenza A/H3N2 infection were assessed. A higher number of aa mismatches in epitope A between the vaccine and locally circulating viruses correlated with more severe influenza infection, although this correlation was most significant with pre-existing comorbidities. A practical application of this finding would be to monitor patients (especially those in high-risk groups) infected with such viruses more closely, as they are at increased risk of developing more serious disease. Epidemiologically, it was of interest to note that viruses from subclade 3A of Victoria/208 strain were not detected in Singapore between 2009 and 2012. By contrast, these viruses were detected at a prevalence of up to 40% in the 2011-2012 influenza seasons in other regions of the Northern and Southern hemispheres. Such findings support the rationale for more regionally customized seasonal influenza vaccine compositions to optimize the protection of the population against locally circulating virus strains.
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Affiliation(s)
- Hong Kai Lee
- Department of Pathology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Department of Laboratory Medicine, National University Hospital, National University Health System, Singapore
| | - Julian Wei-Tze Tang
- Clinical Microbiology, University Hospitals of Leicester NHS Trust, Leicester, United Kingdom.
| | - Tze Ping Loh
- Department of Laboratory Medicine, National University Hospital, National University Health System, Singapore
| | | | - Evelyn Siew-Chuan Koay
- Department of Pathology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; Department of Laboratory Medicine, National University Hospital, National University Health System, Singapore.
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Kelly HA. Safety and effectiveness of influenza vaccines. Med J Aust 2015; 201:560-1. [PMID: 25390245 DOI: 10.5694/mja14.01281] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 10/07/2014] [Indexed: 11/17/2022]
Affiliation(s)
- Heath A Kelly
- Victorian Infectious Diseases Reference Laboratory, Peter Doherty Institute, Melbourne, VIC, Australia.
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Sullivan SG, Feng S, Cowling BJ. Potential of the test-negative design for measuring influenza vaccine effectiveness: a systematic review. Expert Rev Vaccines 2014; 13:1571-91. [PMID: 25348015 PMCID: PMC4277796 DOI: 10.1586/14760584.2014.966695] [Citation(s) in RCA: 120] [Impact Index Per Article: 12.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
BACKGROUND The test-negative design is a variant of the case-control study being increasingly used to study influenza vaccine effectiveness (VE). In these studies, patients with influenza-like illness are tested for influenza. Vaccine coverage is compared between those testing positive versus those testing negative to estimate VE. OBJECTIVES We reviewed features in the design, analysis and reporting of 85 published test-negative studies. DATA SOURCES Studies were identified from PubMed, reference lists and email updates. Study eligibility: All studies using the test-negative design reporting end-of-season estimates were included. STUDY APPRAISAL Design features that may affect the validity and comparability of reported estimates were reviewed, including setting, study period, source population, case definition, exposure and outcome ascertainment and statistical model. RESULTS There was considerable variation in the analytic approach, with 68 unique statistical models identified among the studies. CONCLUSION Harmonization of analytic approaches may improve the potential for pooling VE estimates.
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Affiliation(s)
- Sheena G Sullivan
- WHO Collaborating Centre for Reference and Research on Influenza, Peter Doherty Institute for Infection and Immunity, 792 Elizabeth St, Melbourne VIC 3000, Australia
| | - Shuo Feng
- School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Benjamin J Cowling
- School of Public Health, Li Ka Shing Faculty of Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
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Understanding influenza vaccine protection in the community: an assessment of the 2013 influenza season in Victoria, Australia. Vaccine 2014; 33:341-5. [PMID: 25448093 DOI: 10.1016/j.vaccine.2014.11.019] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2014] [Revised: 11/05/2014] [Accepted: 11/12/2014] [Indexed: 11/21/2022]
Abstract
BACKGROUND The influenza virus undergoes frequent antigenic drift, necessitating annual review of the composition of the influenza vaccine. Vaccination is an important strategy for reducing the impact and burden of influenza, and estimating vaccine effectiveness (VE) each year informs surveillance and preventative measures. We aimed to describe the influenza season and to estimate the effectiveness of the influenza vaccine in Victoria, Australia, in 2013. METHODS Routine laboratory notifications, general practitioner sentinel surveillance (including a medical deputising service) data, and sentinel hospital admission surveillance data for the influenza season (29 April to 27 October 2013) were collated in Victoria, Australia, to describe influenza-like illness or confirmed influenza during the season. General practitioner sentinel surveillance data were used to estimate VE against medically-attended laboratory confirmed influenza. VE was estimated using the case test negative design as 1-adjusted odds ratio (odds of vaccination in cases compared with controls) × 100%. Cases tested positive for influenza while non-cases (controls) tested negative. Estimates were adjusted for age group, week of onset, time to swabbing and co-morbidities. RESULTS The 2013 influenza season was characterised by relatively low activity with a late peak. Influenza B circulation preceded that of influenza A(H1)pdm09, with very little influenza A(H3) circulation. Adjusted VE for all influenza was 55% (95%CI: -11, 82), for influenza A(H1)pdm09 was 43% (95%CI: -132, 86), and for influenza B was 56% (95%CI: -51, 87) Imputation of missing data raised the influenza VE point estimate to 64% (95%CI: 13, 85). CONCLUSIONS Clinicians can continue to promote a positive approach to influenza vaccination, understanding that inactivated influenza vaccines prevent at least 50% of laboratory-confirmed outcomes in hospitals and the community.
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Darvishian M, Bijlsma MJ, Hak E, van den Heuvel ER. Effectiveness of seasonal influenza vaccine in community-dwelling elderly people: a meta-analysis of test-negative design case-control studies. THE LANCET. INFECTIOUS DISEASES 2014; 14:1228-39. [PMID: 25455990 DOI: 10.1016/s1473-3099(14)70960-0] [Citation(s) in RCA: 81] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND The application of test-negative design case-control studies to assess the effectiveness of influenza vaccine has increased substantially in the past few years. The validity of these studies is predicated on the assumption that confounding bias by risk factors is limited by design. We aimed to assess the effectiveness of influenza vaccine in a high-risk group of elderly people. METHODS We searched the Cochrane library, Medline, and Embase up to July 13, 2014, for test-negative design case-control studies that assessed the effectiveness of seasonal influenza vaccine against laboratory confirmed influenza in community-dwelling people aged 60 years or older. We used generalised linear mixed models, adapted for test-negative design case-control studies, to estimate vaccine effectiveness according to vaccine match and epidemic conditions. FINDINGS 35 test-negative design case-control studies with 53 datasets met inclusion criteria. Seasonal influenza vaccine was not significantly effective during local virus activity, irrespective of vaccine match or mismatch to the circulating viruses. Vaccination was significantly effective against laboratory confirmed influenza during sporadic activity (odds ratio [OR] 0·69, 95% CI 0·48-0·99) only when the vaccine matched. Additionally, vaccination was significantly effective during regional (match: OR 0·42, 95% CI 0·30-0·60; mismatch: OR 0·57, 95% CI 0·41-0·79) and widespread (match: 0·54, 0·46-0·62; mismatch: OR 0·72, 95% CI 0·60-0·85) outbreaks. INTERPRETATION Our findings show that in elderly people, irrespective of vaccine match, seasonal influenza vaccination is effective against laboratory confirmed influenza during epidemic seasons. Efforts should be renewed worldwide to further increase uptake of the influenza vaccine in the elderly population. FUNDING None.
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Affiliation(s)
- Maryam Darvishian
- Department of Epidemiology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands; Unit of PharmacoEpidemiology and PharmacoEconomics (PE2), Department of Pharmacy, University of Groningen, Groningen, Netherlands
| | - Maarten J Bijlsma
- Unit of PharmacoEpidemiology and PharmacoEconomics (PE2), Department of Pharmacy, University of Groningen, Groningen, Netherlands
| | - Eelko Hak
- Department of Epidemiology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands; Unit of PharmacoEpidemiology and PharmacoEconomics (PE2), Department of Pharmacy, University of Groningen, Groningen, Netherlands
| | - Edwin R van den Heuvel
- Department of Epidemiology, University Medical Center Groningen, University of Groningen, Groningen, Netherlands; Department of Mathematics and Computer Science, Eindhoven University of Technology, Eindhoven, Netherlands.
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Sullivan SG, Chilver MBN, Higgins G, Cheng AC, Stocks NP. Influenza vaccine effectiveness in Australia: results from the Australian Sentinel Practices Research Network. Med J Aust 2014; 201:109-11. [PMID: 25045991 DOI: 10.5694/mja14.00106] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2014] [Accepted: 06/18/2014] [Indexed: 11/17/2022]
Abstract
OBJECTIVE To estimate influenza vaccine coverage and effectiveness against medically attended laboratory-confirmed influenza for the 2012 season. DESIGN, SETTING AND PARTICIPANTS Test-negative design involving patients recruited as part of the Australian Sentinel Practices Research Network, a network of sentinel general practitioners throughout Australia. Throughout 2012, at the discretion of the GP at one of 102 participating practices, patients presenting with influenza-like illness were swabbed and included in the study. MAIN OUTCOME MEASURE Influenza vaccine effectiveness (VE) estimated as (1-OR)*100% by logistic regression. RESULTS 1775 patients were swabbed. The epidemic period was identified as Weeks 10 to 43 of 2012. After exclusions, there were 1414 patients for the VE analysis, including 593 (42%) who tested influenza-positive and 821 who tested negative. 27% of test-negative patients were vaccinated, of whom most were aged 50 years and over. The overall VE, adjusted for age group, month of presentation and state or territory, was 23% (95% CI, -4% to 43%) against all influenza types, 15% (95% CI, -17% to 38%) against influenza A, 13% (95% CI, -20% to 36%) against influenza A(not H1) and 53% (95% CI, 5% to 77%) against influenza B. CONCLUSION Vaccination against influenza was modestly protective, reducing the risk of medical presentation with influenza by around 23%.
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Affiliation(s)
- Sheena G Sullivan
- WHO Collaborating Centre for Reference and Research on Influenza, Peter Doherty Institute for Infection and Immunity, Melbourne, VIC, Australia.
| | - Monique B-N Chilver
- Discipline of General Practice, University of Adelaide, Adelaide, SA, Australia
| | - Geoff Higgins
- Microbiology and Infectious Diseases, SA Pathology, Adelaide, SA, Australia
| | - Allen C Cheng
- Department of Epidemiology and Preventive Medicine, Monash University, Melbourne, VIC, Australia
| | - Nigel P Stocks
- Discipline of General Practice, University of Adelaide, Adelaide, SA, Australia
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Influenza vaccine effectiveness estimates for Western Australia during a period of vaccine and virus strain stability, 2010 to 2012. Vaccine 2014; 32:6312-8. [PMID: 25223268 DOI: 10.1016/j.vaccine.2014.08.066] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 07/04/2014] [Accepted: 08/27/2014] [Indexed: 11/22/2022]
Abstract
During 2010-2012 the strain composition of the influenza vaccine in the Southern Hemisphere did not change, but the circulating virus type/subtype did. We pooled data for these years from the Western Australian sentinel medical practice surveillance system for influenza to estimate vaccine effectiveness (VE) by influenza virus type and subtype. A case test-negative design was used with VE estimated as (1-odds ratio)×100%. There were 2182 patients included in the analysis across the 3 years studied. The predominant subtype was A/H1pdm09 in 2010 and 2011, and A/H3 in 2012. The overall adjusted VE estimate against all influenza for 2010-2012 was 51% (95% CI: 36, 63). Estimates were highest against A/H1pdm09 at 74% (95% CI: 47, 87), followed by 56% (95% CI: 33, 71) for influenza B and lowest against A/H3 at 39% (95% CI: 13, 57). When analyses were restricted to compare influenza-positive patients with patients who tested positive for a non-influenza virus, overall adjusted VE was 59% (95% CI: 39, 72). These results suggest moderate protection against influenza by vaccination in Western Australia over the period 2010-2012, and are consistent with findings from other settings.
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Cowling BJ, Chan KH, Feng S, Chan ELY, Lo JYC, Peiris JSM, Chiu SS. The effectiveness of influenza vaccination in preventing hospitalizations in children in Hong Kong, 2009-2013. Vaccine 2014; 32:5278-84. [PMID: 25092636 PMCID: PMC4165553 DOI: 10.1016/j.vaccine.2014.07.084] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2014] [Revised: 07/11/2014] [Accepted: 07/22/2014] [Indexed: 11/28/2022]
Abstract
Background Influenza vaccination is widely recommended every year to protect individuals against influenza virus infection and illness. There are few published estimates of influenza vaccine effectiveness against hospitalization in children or from subtropical regions. Methods We conducted a test-negative year-round study between October 2009 and September 2013, recruiting children 6 months to 17 years of age admitted to two hospitals in Hong Kong with a febrile acute respiratory infection. Cases were tested for influenza A and B and conditional logistic regression was used to estimate vaccine effectiveness comparing influenza vaccination history of the trivalent influenza vaccine (TIV) among patients testing positive versus negative for influenza, adjusting for age and sex and matching by calendar week of recruitment. Results Overall vaccine effectiveness against hospitalization with laboratory-confirmed influenza A and B was estimated to be 61.7% (95% CI: 43.0%, 74.2%). The estimated vaccine effectiveness against A(H3N2) was 36.6% (95% CI: −25.5%, 67.9%) compared to 71.5% (95% CI: 39.4%, 86.6%) for A(H1N1)pdm09 and 68.8% (95% CI: 41.6%, 83.3%) for B. Conclusions Vaccine effectiveness against hospitalization in children varied from year to year, but was moderate to high overall even in an area with influenza activity throughout the year.
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Affiliation(s)
- Benjamin J Cowling
- Division of Epidemiology and Biostatistics, School of Public Health, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Kwok-Hung Chan
- Department of Microbiology, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Shuo Feng
- Division of Epidemiology and Biostatistics, School of Public Health, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Eunice L Y Chan
- Department of Pediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Janice Y C Lo
- Public Health Laboratory Services Branch, Centre for Health Protection, Department of Health, Hong Kong Special Administrative Region, China
| | - J S Malik Peiris
- Division of Public Health Laboratory Sciences, School of Public Health, The University of Hong Kong, Hong Kong Special Administrative Region, China; Centre for Influenza Research, The University of Hong Kong, Hong Kong Special Administrative Region, China
| | - Susan S Chiu
- Department of Pediatrics and Adolescent Medicine, The University of Hong Kong, Hong Kong Special Administrative Region, China.
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Affiliation(s)
- H Kelly
- Victorian Infectious Diseases Reference Laboratory, North Melbourne, Victoria, Australia
- National Centre for Epidemiology and Population Health, Australian National University, Canberra, Australia
| | - B J Cowling
- Division of Epidemiology and Biostatistics, School of Public Health, Li Ka Shing Faculty of Medicine, the University of Hong Kong, Hong Kong Special Administrative Region, China
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