High-Dose Quadrivalent Influenza Vaccine for Prevention of Cardiovascular and Respiratory Hospitalizations in Older Adults

BACKGROUND

We assessed the relative vaccine effectiveness (rVE) of high-dose quadrivalent influenza vaccine (QIV-HD) versus standard-dose quadrivalent influenza vaccine (QIV-SD) in preventing respiratory or cardiovascular hospitalizations in older adults.

METHODS

FinFluHD was a phase 3b/4 modified double-blind, randomized pragmatic trial. Enrolment of 121,000 adults ≥65 years was planned over three influenza seasons (October to December 2019-2021). Participants received a single injection of QIV-HD or QIV-SD. The primary endpoint was first occurrence of an unscheduled acute respiratory or cardiovascular hospitalization (ICD-10 primary discharge J/I codes), from ≥14 days post-vaccination until May 31. The study was terminated after one season due to COVID-19; follow-up data for 2019-2020 are presented.

RESULTS

33,093 participants were vaccinated (QIV-HD, n = 16,549; QIV-SD, n = 16,544); 529 respiratory or cardiovascular hospitalizations (QIV-HD, n = 257; QIV-SD, n = 272) were recorded. The rVE of QIV-HD versus QIV-SD to prevent respiratory/cardiovascular hospitalizations was 5.5% (95% CI, -12.4 to 20.7). When prevention of respiratory and cardiovascular hospitalizations were considered separately, rVE estimates of QIV-HD versus QIV-SD were 5.4% (95% CI, -28.0 to 30.1) and 7.1% (95% CI, -15.0 to 25.0), respectively. Serious adverse reactions were <0.01% in both groups.

CONCLUSIONS

Despite insufficient statistical power due to the impact of COVID-19, rVE point estimates demonstrated a trend toward a benefit of QIV-HD over QIV-SD. QIV-HD was associated with lower respiratory or cardiovascular hospitalization rates than QIV-SD, with a comparable safety profile. Adequately powered studies conducted over multiple influenza seasons are needed to determine statistical significance of QIV-HD compared with QIV-SD against preventing respiratory and cardiovascular hospitalizations.

TRIAL REGISTRATION

ClinicalTrials.gov number: NCT04137887.

Effectiveness of trivalent influenza vaccines against hospitalizations due to laboratory-confirmed influenza a in the elderly: Comparison of test-negative design with register-based designs

INTRODUCTION

Measuring influenza vaccine effectiveness (IVE) seasonally is important and has been conducted utilizing several observational study designs. The active test-negative design has been most widely used and the validity of passive register-based studies has been debated. We aimed to explore the potential differences, advantages, and weaknesses of different study designs in estimating influenza vaccine effectiveness.

METHODS

We compared three study designs in estimating IVE against hospitalization in the elderly aged 65 years or more over three influenza seasons 2015/16, 2016/17 and 2017/18. Designs compared were active test-negative design (TND), register-based cohort design and register-based case-control design with different selection criteria for cases and controls.

RESULTS

Adjusted IVE estimates for the three consecutive seasons 2015-18 in active test-negative design were 82% (95% confidence interval 26, 96), 21% (-179, 77), 15% (-113, 66). For case-control design, estimates from different analyses ranged in 2015/16 from 47% (-16, 76) to 52% (-48, 84), in 2016/17 from 10% (-42, 43) to 29% (-20, 58), and in 2017/18 from -27% (-91, 15) to 1% (-40, 30). In the cohort design, the adjusted IVE estimates were 48% (-9, 75), 29% (1, 49), 13% (-21, 37) for the three seasons.

CONCLUSIONS

The register-based cohort design produced results more concordant with the active test-negative design than the case-control design. Furthermore, the register-based cohort design yielded most precise estimates with narrower confidence intervals. In Finland with the availability of near real-time nationwide register data, the register-based cohort design is the method of choice to continue the annual surveillance of influenza vaccine effectiveness.

The prevalence of otitis media in 2-3 year old Cameroonian children estimated by tympanometry

BACKGROUND

Acute otitis media is a common illness in children under-five years of age and associated with major health care resources in high-income countries. However, there is paucity of data on its epidemiology and clinical presentation in low-income countries. We estimated the prevalence of otitis media and assessed risk factors among children in Cameroon.

METHODS

A community-based cross-sectional prevalence study of otitis media (OM) was performed on randomly selected children aged 2-3 years in Yaoundé, Cameroon from March to June 2013. OM was assessed by clinical inspection for chronic suppurative otitis media (CSOM) and tympanometry for otitis media with effusion (OME). CSOM was defined as draining of the middle ear with duration of more than two weeks and OME was defined as a flat 'type B' tympanogram.

RESULTS

Out of 529 children enrolled in the study, 433 (56% males) subjects with available tympanograms were evaluated. Altogether, 9.7% (42/433) of children met the case definition of CSOM, OME or its complications. This consisted of 3 (0.7%) children identified with unilateral CSOM; 7 (1.6%) children with bilateral OME; 31 (7.2%) with unilateral OME and 1 (0.2%) subject with unilateral dry tympanic membrane perforation. Logistic regression analyses showed statistically significant association between OM and parental reporting of "current symptoms of upper respiratory tract infections", Prevalence Odds Ratio (POR) = 3.71; 95% CI = 1.69-8.14).

CONCLUSION

As many as two out of a hundred children between the ages of 2-3 years were affected by significant middle ear disease i.e. CSOM or bilateral OME. These data could be useful as a baseline for estimating the impact of pneumococcal conjugate vaccines (PCV13) introduced in July 2011 for infants in Cameroon.

Low 2016/17 season vaccine effectiveness against hospitalised influenza A(H3N2) among elderly: awareness warranted for 2017/18 season

In a multicentre European hospital study we measured influenza vaccine effectiveness (IVE) against A(H3N2) in 2016/17. Adjusted IVE was 17% (95% confidence interval (CI): 1 to 31) overall; 25% (95% CI: 2 to 43) among 65–79-year-olds and 13% (95% CI: −15 to 30) among those ≥ 80 years. As the A(H3N2) vaccine component has not changed for 2017/18, physicians and public health experts should be aware that IVE could be low where A(H3N2) viruses predominate.

2015/16 seasonal vaccine effectiveness against hospitalisation with influenza A(H1N1)pdm09 and B among elderly people in Europe: results from the I-MOVE+ project

We conducted a multicentre test-negative case-control study in 27 hospitals of 11 European countries to measure 2015/16 influenza vaccine effectiveness (IVE) against hospitalised influenza A(H1N1)pdm09 and B among people aged ≥ 65 years. Patients swabbed within 7 days after onset of symptoms compatible with severe acute respiratory infection were included. Information on demographics, vaccination and underlying conditions was collected. Using logistic regression, we measured IVE adjusted for potential confounders. We included 355 influenza A(H1N1)pdm09 cases, 110 influenza B cases, and 1,274 controls. Adjusted IVE against influenza A(H1N1)pdm09 was 42% (95% confidence interval (CI): 22 to 57). It was 59% (95% CI: 23 to 78), 48% (95% CI: 5 to 71), 43% (95% CI: 8 to 65) and 39% (95% CI: 7 to 60) in patients with diabetes mellitus, cancer, lung and heart disease, respectively. Adjusted IVE against influenza B was 52% (95% CI: 24 to 70). It was 62% (95% CI: 5 to 85), 60% (95% CI: 18 to 80) and 36% (95% CI: -23 to 67) in patients with diabetes mellitus, lung and heart disease, respectively. 2015/16 IVE estimates against hospitalised influenza in elderly people was moderate against influenza A(H1N1)pdm09 and B, including among those with diabetes mellitus, cancer, lung or heart diseases.

Repeated seasonal influenza vaccination among elderly in Europe: Effects on laboratory confirmed hospitalised influenza

In Europe, annual influenza vaccination is recommended to elderly. From 2011 to 2014 and in 2015-16, we conducted a multicentre test negative case control study in hospitals of 11 European countries to measure influenza vaccine effectiveness (IVE) against laboratory confirmed hospitalised influenza among people aged ≥65years. We pooled four seasons data to measure IVE by past exposures to influenza vaccination. We swabbed patients admitted for clinical conditions related to influenza with onset of severe acute respiratory infection ≤7days before admission. Cases were patients RT-PCR positive for influenza virus and controls those negative for any influenza virus. We documented seasonal vaccination status for the current season and the two previous seasons. We recruited 5295 patients over the four seasons, including 465A(H1N1)pdm09, 642A(H3N2), 278 B case-patients and 3910 controls. Among patients unvaccinated in both previous two seasons, current seasonal IVE (pooled across seasons) was 30% (95%CI: -35 to 64), 8% (95%CI: -94 to 56) and 33% (95%CI: -43 to 68) against influenza A(H1N1)pdm09, A(H3N2) and B respectively. Among patients vaccinated in both previous seasons, current seasonal IVE (pooled across seasons) was -1% (95%CI: -80 to 43), 37% (95%CI: 7-57) and 43% (95%CI: 1-68) against influenza A(H1N1)pdm09, A(H3N2) and B respectively. Our results suggest that, regardless of patients' recent vaccination history, current seasonal vaccine conferred some protection to vaccinated patients against hospitalisation with influenza A(H3N2) and B. Vaccination of patients already vaccinated in both the past two seasons did not seem to be effective against A(H1N1)pdm09. To better understand the effect of repeated vaccination, engaging in large cohort studies documenting exposures to vaccine and natural infection is needed.

Similar Antibody Levels in 3-Year-Old Children Vaccinated Against Measles, Mumps, and Rubella at the Age of 12 Months or 18 Months

BACKGROUND

Measles-mumps-rubella (MMR) vaccinations have been offered to Finnish children at 14-18 months and 6 years of age. In May 2011, the recommended age for the first vaccine dose was lowered to 12 months because of the European measles epidemic.

METHODS

Fingertip capillary blood samples were collected from 3-year-old Finnish children vaccinated once with MMR vaccine at 11-19 months of age. The immunoglobulin G (IgG) antibodies to all 3 MMR antigens were measured with enzyme-linked immunosorbent assay. Neutralizing antibodies and the avidity of antibodies were measured for measles virus.

RESULTS

From April through October 2013, 187 children were enrolled. Equally high proportions of the samples were seropositive for measles virus, mumps virus, or rubella virus antibodies, and there were no significant differences in the IgG antibody concentrations in children vaccinated at 11-13 months of age, compared with those vaccinated at 17-19 months of age. However, among children vaccinated at 11-13 months of age, boys had lower antibody concentrations than girls. Neutralizing measles virus antibody titers were above the threshold for protective immunity in all 78 samples analyzed. The measles virus antibody avidity indexes were high for all children.

CONCLUSIONS

MMR induces similar antibody responses in 12-month-old children as compared to 18-month-old children, but in boys increasing age appears to improve the antibody responses.

Effectiveness of pandemic and seasonal influenza vaccines in preventing laboratory-confirmed influenza in adults: a clinical cohort study during epidemic seasons 2009-2010 and 2010-2011 in Finland

Background

One dose of pandemic influenza vaccine Pandemrix (GlaxoSmithKline) was offered to the entire population of Finland in 2009–10. We conducted a prospective clinical cohort study to determine the vaccine effectiveness in preventing febrile laboratory-confirmed influenza infection during the influenza season 2009–10 and continued the study in 2010–11.

Methods

In total, 3,518 community dwelling adults aged 18–75 years living in Tampere city were enrolled. The participants were not assigned to any vaccination regimen, but they could participate in the study regardless of their vaccination status or intention to be vaccinated with the pandemic or seasonal influenza vaccine. They were asked to report if they received Pandemrix in 2009–10 and/or trivalent influenza vaccine in 2010–11. Vaccinations were verified from medical records. The participants were instructed to report all acute symptoms of respiratory tract infection with fever (at least 38°C) and pneumonias to the study staff. Nasal and oral swabs were obtained within 5–7 days after symptom onset and influenza-specific RNA was identified by reverse transcription polymerase chain reaction.

Results

In 2009–10, the estimated vaccine effectiveness was 81% (95%CI 30–97). However, the vaccine effectiveness could not be estimated reliably, because only persons in prioritized groups were vaccinated before/during the first pandemic wave and many participants were enrolled when they already had the symptoms of A(H1N1)pdm09 influenza infection. In 2010–11, 2,276 participants continued the follow-up. The vaccine effectiveness, adjusted for potential confounding factors was 81% (95%CI 41–96) for Pandemrix only and 88% (95%CI 63–97) for either Pandemrix or trivalent influenza vaccine 2010–11 or both, respectively.

Conclusion

Vaccination with an AS03-adjuvanted pandemic vaccine in 2009–10 was still effective in preventing A(H1N1)pdm09 influenza during the following epidemic season in 2010–11.

Trial Registration

ClinicalTrials.gov NCT01024725. NCT01206114.

The value of nasopharyngeal culture in predicting the etiology of acute otitis media in children less than two years of age

BACKGROUND

In selecting treatment of acute otitis media (AOM), knowledge of its etiology would be valuable. We revisited the possibility to use the nasopharyngeal culture of Streptococcus pneumoniae (Pnc) and Haemophilus influenzae (Hi) for predicting their presence in the middle ear fluid (MEF) during AOM.

METHODS

The sensitivity, specificity, positive predictive value (PPV) and negative predictive value (NPV) of bacterial culture of the nasopharyngeal aspirate (NPA) in predicting the presence of the same pathogen in the MEF were assessed during AOM events among children followed from 2 to 24 months of age.

RESULTS

The data comprised 586 AOM events. For Pnc, the sensitivity and NPV were high, 99% (95% confidence interval = 95-100%) and >99% (97-100%), respectively. The specificity and PPV were relatively low, 63% (57-68%) and 50% (43-56%). For Hi, the sensitivity and the NPV were lower (77%, 69-83% and 93%, 90-95%) than for Pnc, but the specificity and the PPV were higher (88%, 85-91% and 64%, 56-71%). The quantity of Pnc and Hi in the NPA was clearly related to their presence in the MEF. If both Pnc and Hi were found in the nasopharynx, Hi was more likely cultured from MEF.

CONCLUSION

Together with clinical and epidemiologic features of AOM, the nasopharyngeal culture can be helpful in selecting specific antimicrobial therapy.

Pneumococcal acute otitis media in relation to pneumococcal nasopharyngeal carriage

BACKGROUND

Acute otitis media (AOM) is closely associated with viral upper respiratory tract infections, but the most common microbial agent found in the middle ear fluid during AOM is Streptococcus pneumoniae (Pnc). Pnc is also a common colonizer of the nasopharynx, and its prevalence is further increased during the viral infection. The aim of this study was to investigate the interplay between viral infection, pneumococcal acquisition and carriage in the development of Pnc AOM.

METHODS

Pnc carriage was assessed in a longitudinal study of 329 infants at scheduled visits at 3, 6, 9, 12, 15 and 18 months of age (N = 1715). The clinical outcome of the first episode of respiratory infection ("sick visit," N = 774) in the following 3-month period was recorded. The occurrence and timing of Pnc AOM in relation to serotype specific carriage at the start of the observation period were assessed.

RESULTS

The occurrence, timing and duration of symptoms of the sick visits or the frequency of overall AOM were not associated with preceding pneumococcal carriage. Pnc AOM was in each case associated with concurrent carriage and 3.8 times (95% confidence interval, 1.4-10.0) more often with carriage acquired after the start of the observation period than with carriage already present at the scheduled visit. In all, 79% (55 of 70) of Pnc AOM events were caused by a serotype acquired after the start of the period.

CONCLUSION

The majority of Pnc AOM events develop in association with newly acquired carriage of pneumococcus.

Invasiveness of serotypes and clones of Streptococcus pneumoniae among children in Finland

Streptococcus pneumoniae (the pneumococcus) causes diseases from otitis media to life-threatening invasive infection. The species is extremely antigenically and clonally diverse. We wished to determine odds ratios (ORs) for serotypes and clones of S. pneumoniae that cause invasive disease in Finland. A total of 224 isolates of S. pneumoniae from cases of invasive disease in children <2 years of age in Finland between 1995 and 1999 were serotyped, and sequence types (STs) were determined by multilocus sequence typing. These STs were compared with a previously published carriage data set. STs from invasive disease were significantly less diverse than those from carriage (invasive disease, 0.038 +/- 0.01; carriage, 0.019 +/- 0.005). The ORs of serotypes 14, 18C, 19A, and 6B were significantly greater than 1, indicating association with invasive disease. The ORs of 6A and 11A were significantly less than 1. The difference between 6A and 6B is significant, which suggests that relatively subtle changes in the capsule may have a dramatic effect upon disease potential. We found that ST 156, the Spain(9V)-3 clone which mainly expressed serotype 14 in Finland, is strongly associated with invasive disease (OR, 10.1; 95% confidence interval, 1.3 to 79.5). Significant associations with invasive disease were also detected for STs 482, 191, 124, and 138, and associations with carriage were detected for STs 485 and 62. These results demonstrate the invasive phenotype of the serotype 14 variant of the Spain(9V)-3 clone and differences between members of the same serogroup in invasive disease potential.

Nasopharyngeal carriage of Streptococcus pneumoniae in Finnish children younger than 2 years old

To describe the natural course of nasopharyngeal carriage of Streptococcus pneumoniae and its relationship to acute otitis media (AOM), 329 Finnish children were followed from ages 2 to 24 months. In total, 3024 nasopharyngeal (NP) swabs (obtained at 10 scheduled healthy visits) and 2007 NP aspirates (obtained during respiratory infections) were cultured. Carriage during health increased gradually (9%-43%) with age. Within 4 age intervals, carriage was lower during health (13%-43%) than during respiratory infection without AOM (22%-45%). Higher proportions of positive samples were found during AOM (45%-56%), in particular during pneumococcal AOM (97%-100%). Antimicrobial treatment reduced carriage only temporarily. The most frequent NP serotypes were 6B, 6A, 11, 19F, and 23F. Both age and health status were important determinants of NP carriage of S. pneumoniae and these features should be considered carefully during analysis of carriage rates.