Seasonal influenza vaccination coverage among adult populations in the United States, 2005-2011

The most effective strategy for preventing influenza is annual vaccination. We analyzed 2005-2011 data from the National Health Interview Survey (NHIS), using Kaplan-Meier survival analysis to estimate cumulative proportions of persons reporting influenza vaccination in the 2004-2005 through 2010-2011 seasons for persons aged ≥18, 18-49, 50-64, and ≥65 years, persons with high-risk conditions, and health-care personnel. We compared vaccination coverage by race/ethnicity within each age and high-risk group. Vaccination coverage among adults aged ≥18 years increased from 27.4% during the 2005-2006 influenza season to 38.1% during the 2010-2011 season, with an average increase of 2.2% annually. From the 2005-2006 season to the 2010-2011 season, coverage increased by 10-12 percentage points for all groups except adults aged ≥65 years. Coverage for the 2010-2011 season was 70.2% for adults aged ≥65 years, 43.7% for adults aged 50-64 years, 36.7% for persons aged 18-49 years with high-risk conditions, and 55.8% for health-care personnel. In most subgroups, coverage during the 2010-2011 season was significantly lower among non-Hispanic blacks and Hispanics than among non-Hispanic whites. Vaccination coverage among adults under age 65 years increased from 2005-2006 through 2010-2011, but substantial racial/ethnic disparities remained in most age groups. Targeted efforts are needed to improve influenza vaccination coverage and reduce disparities.

Effectiveness of the influenza vaccine at preventing hospitalization due to acute exacerbation of cardiopulmonary disease in Korea from 2011 to 2012

There is a lack of targeted studies to validate the effectiveness of influenza vaccination on the reduction in influenza-related hospitalizations among patients with co-morbidities. In this study, we estimate the effectiveness of influenza vaccination on preventing hospitalizations in persons with cardiopulmonary disease and establish an evidence base for recommendations on influenza vaccination in this population. During the influenza epidemic in 2011-2012, we performed a multicenter, retrospective case-control study. Cases were patients hospitalized due to acute exacerbation of asthma, COPD, ischemic heart disease (IHD), and congestive heart failure (CHF). Controls were selected from outpatients who visited study hospitals but who were not hospitalized. Cases and controls were matched 1:1 based on age, gender, and date of hospital visit. Conditional logistic regression analyses were used to determine the effectiveness of vaccination. Between 25 December 2011 and 5 May 2012, 828 of each hospitalized and control subjects were identified. The influenza vaccination rate of the hospitalized and non-hospitalized patients was 54.2% and 60.4%, respectively (P = 0.006). The overall vaccine effectiveness for preventing hospitalization was 33.7% (95% confidence interval [CI] 14.0-49.0%; P = 0.002). Conditional logistic regression analysis showed that influenza vaccination significantly reduced the risk of hospitalization, especially due to acute exacerbation of IHD and CHF, in patients aged 65 y and older. The estimated vaccine effectiveness in these patients was 56.0% (95% CI 32.1-71.4%, P = 0.002). Influenza vaccination was associated with a reduction in the risk of hospitalization due to acute exacerbation of cardiopulmonary disease. We recommend the vaccine be given primarily to patients with underlying cardiovascular disease, particularly those 65 y of age and older.

Preventing surgery-induced NK cell dysfunction and cancer metastases with influenza vaccination

Surgical resection is the mainstay of treatment for solid tumors, but the postoperative period is uniquely inclined to the formation of metastases, largely due to the suppression of natural killer (NK) cells. We found that preoperative influenza vaccination prevents postoperative NK-cell dysfunction, attenuating tumor dissemination in murine models and promoting the activation of NK cells in cancer patients.

Age and psychological influences on immune responses to trivalent inactivated influenza vaccine in the meditation or exercise for preventing acute respiratory infection (MEPARI) trial

BACKGROUND

Strategies to improve influenza vaccine protection among elderly individuals are an important research priority. Mindfulness-based stress reduction (MBSR) and exercise have been shown to affect aspects of immune function in some populations. We hypothesized that influenza vaccine responses may be enhanced with meditation or exercise training as compared with controls.

RESULTS

No differences in vaccine responses were found comparing control to MBSR or exercise. Individuals achieving seroprotective levels of influenza antibody ≥160 units had higher optimism, less anxiety, and lower perceived stress than the nonresponders. Age correlated with influenza antibody responses, but not with IFNγ or IL-10 production.

CONCLUSION

The MBSR and exercise training evaluated in this study failed to enhance immune responses to influenza vaccine. However, optimism, perceived stress, and anxiety were correlated in the expected directions with antibody responses to influenza vaccine.

METHODS

Healthy individuals≥50 y were randomly assigned to exercise (n=47) or MBSR (n=51) training or a waitlist control condition (n=51). Each participant received trivalent inactivated influenza vaccine after 6 weeks, and had blood draws prior to and 3 and 12 weeks after immunization. Serum influenza antibody, nasal immunoglobulin A, and peripheral blood mononuclear cell interferon-γ (IFNγ) and interleukin-10 (IL-10) concentrations were measured. Measures of optimism, perceived stress, and anxiety were obtained over the course of the study. Seroprotection was defined as an influenza antibody concentration≥160 units. Vaccine responses were compared using ANOVA, t tests, and Kruskal-Wallis tests. The correlation between vaccine responses and age was examined with the Pearson test.

Clinical validation of IFNγ/IL-10 and IFNγ/IL-2 FluoroSpot assays for the detection of Tr1 T cells and influenza vaccine monitoring in humans

The type of T cell polarization and simultaneous production of multiple cytokines have been correlated with vaccine efficacy. ELISpot is a T cell detection technique optimized for the measurement of a secreted cytokine at the single cell level. The FluoroSpot assay differs from ELISpot by the use of multiple fluorescent-labeled anticytokine detection antibodies, allowing optimal measurement of multiple cytokines. In the present study, we show that an IFNγ/IL-10 FluoroSpot assay is more sensitive than flow cytometry to detect Tr1 regulatory T cells, an immunosuppressive T cell population characterized by the production of IL-10 and IFNγ. As many tolerogenic vaccines are designed to induce these Tr1 cells, this FluoroSpot test could represent a standard method for the detection of these cells in the future. The use of an IFNγ/IL-2 FluoroSpot assay during influenza vaccine monitoring showed that the influenza-specific IL-2-producing T-cell response was the dominant response both before and after vaccine administration. This study therefore questions the rationale of using the single-color IFNγ ELISpot as the standard technique to monitor vaccine-specific T-cell response. Using this same test, a trend was also observed between baseline levels of IFNγ T cell response and T cell vaccine response. In addition, a lower IFNγ+IL-2+ T-cell response after vaccine was observed in the group of patients treated with TNFα inhibitors (P=0.08). This study therefore supports the use of the FluoroSpot assay due to its robustness, versatility and the complementary information that it provides compared with ELISpot or flow cytometry to monitor vaccine-specific T-cell responses.

Safety of MF59-adjuvanted influenza vaccination in the elderly: results of a comparative study of MF59-adjuvanted vaccine versus nonadjuvanted influenza vaccine in northern Italy

MF59-adjuvanted trivalent influenza vaccine (Novartis Vaccines and Diagnostics, Siena, Italy) has been shown to be more effective than nonadjuvanted vaccine in the elderly population. Here we present results from a large-scale, observational, noninterventional, prospective postlicensure study that evaluated the safety of MF59-adjuvanted vaccine in elderly subjects aged 65 years or more. The study was performed in 5 northern Italian health districts during the 2006–2007, 2007–2008, and 2008–2009 influenza seasons. The choice of vaccine—either adjuvanted vaccine or a nonadjuvanted influenza vaccine—was determined by individual providers on the basis of local influenza vaccination policy. Hospitalizations for potential adverse events of special interest (AESIs) were identified from hospital databases and then reviewed against recognized case definitions to identify confirmed cases of AESI. Cumulative incidences were calculated for AESIs in predefined biologically plausible time windows, as well as in a 6-month window following vaccination. During the 3-year study period, 170,988 vaccine doses were administered to a total of 107,661 persons. Despite the large study size, cases of AESI resulting in hospitalization were rare, and risks of AESI were similar in both the MF59-adjuvanted and nonadjuvanted vaccination groups. In conclusion, similar safety profiles were observed for both nonadjuvanted and MF59-adjuvanted seasonal influenza vaccines in elderly recipients.

A phase II study of an investigational tetravalent influenza vaccine formulation combining MF59®: adjuvanted, pre-pandemic, A/H5N1 vaccine and trivalent seasonal influenza vaccine in healthy adults

An investigational tetravalent vaccine combining pre-pandemic, MF59®-adjuvanted A/H5N1 vaccine with non-adjuvanted, trivalent, seasonal influenza vaccine has been developed, which has the potential to be used for pre-pandemic priming and to improve levels of compliance and coverage. It is important to determine whether the safety and immunogenicity of the combination vaccine is equivalent to that of the two separate vaccines when administered concomitantly. Healthy adults (n=601) were randomly assigned to three vaccination groups to receive either: (1) tetravalent vaccine and placebo concomitantly (in separate arms) on Day 1, followed by A/H5N1 vaccine on Day 22; (2) A/H5N1 vaccine and placebo concomitantly on Day 1, followed by tetravalent vaccine on Day 22; or (3) A/H5N1 and seasonal vaccines concomitantly on Day 1, followed by A/H5N1 vaccine on Day 22. Antibody responses were measured using single radial hemolysis (SRH), haemagglutination inhibition (HI), and microneutralization (MN) assays on Days 1, 22, and 43. Solicited adverse reactions were recorded for seven days after vaccination. Spontaneous adverse events were recorded throughout the study. The tetravalent vaccine elicited antibody titers equivalent to those for separate A/H5N1 and seasonal vaccines, and sufficient to meet the European licensure criteria against A/H5N1 and all three seasonal strains. Local and systemic reactions were mainly mild to moderate. No vaccine-related serious adverse events occurred. These findings demonstrate that MF59-adjuvanted A/H5N1 and seasonal influenza vaccines had an acceptable safety profile and could be effectively administered as a tetravalent formulation, supporting the possibility of integrating pre-pandemic priming into seasonal influenza vaccination programs.

Vaccine effectiveness against laboratory-confirmed influenza hospitalizations among elderly adults during the 2010-2011 season

BACKGROUND

 Although annual influenza immunization is recommended for adults aged ≥65 years due to the substantial burden of illness, the evidence base for this recommendation is weak. Prior observational studies that examined influenza vaccine effectiveness against nonspecific serious outcomes suffered from selection bias and the lack of laboratory confirmation for influenza infection. The objective of this study was to determine the effectiveness of the 2010-2011 seasonal influenza vaccine against laboratory-confirmed influenza hospitalizations among community-dwelling elderly adults, a serious and highly specific outcome.

METHODS

 We conducted a test-negative study of community-dwelling adults aged >65 years in Ontario, Canada. Respiratory specimens collected between 1 December 2010 and 30 April 2011 from patients admitted to acute care hospitals were tested for influenza using nucleic acid amplification techniques. Influenza vaccination was ascertained from physician billing claims through linkage to health administrative datasets.

RESULTS

 Receipt of the 2010-2011 seasonal influenza vaccine was associated with a 42% (95% confidence interval, 29%-53%) reduction in laboratory-confirmed influenza hospitalizations. Vaccine effectiveness estimates were consistent across age groups, by sex, and regardless of outcome severity, timing of testing, and when considering individuals vaccinated <7 or <14 days prior to admission as unvaccinated.

CONCLUSIONS

 Results of this study will better inform decision making regarding influenza vaccination of elderly adults. Similar analyses are needed annually due to antigenic drift and frequent changes in influenza vaccine composition. The linkage of routinely collected laboratory testing and health administrative data represents an efficient method for estimating influenza vaccine effectiveness that complements prospective studies.

Long-term follow-up in patients with HIV vaccinated with pandemic influenza A(H1N1)/09 AS03-adjuvanted split virion vaccine and seasonal trivalent influenza split virion vaccine

Introduction

In Sweden in 2009, two doses of the pandemic influenza A(H1N1)/09 AS03-adjuvanted split virion vaccine were recommended for those with HIV infection along with one dose of seasonal trivalent influenza vaccine (TIV). At that time, no data for HIV patients and their response to the adjuvanted vaccine were available.

Methods

Forty-two HIV-infected individuals were vaccinated with the pandemic vaccine on study days 0 and 28. Twenty-one of them received TIV on day 56 and 21 did not. Serum samples were taken at these time points, and also on day 86 and after 1 year for serologic analyses.

Results

Before vaccination, none of the 42 patients had putatively protective levels of antibodies (haemagglutination inhibition [HI] titres ≥1:40) to the pandemic-like strain A/California/7/2009 H1N1. After dose 1, the seroprotection rate (SPR) and seroconversion rate (SCR) were both 69% (29 of 42). After dose 2, the SPR and SCR were 89 and 86%, respectively. At 1 year, 10 (34%) of 29 had protective antibodies and 16 (62%) of 26 who had had protective antibody levels had lost them. There was a retained factor increase of the geometric mean titre (GMT) of 3.9.

Serological analyses could be performed in 19 subjects who were vaccinated with TIV and in 21 who were not. Protective antibodies to the three strains before vaccination were 20–37%. The SCR was 26% to A/Brisbane/59/2007 H1N1, 47% to A/Uruguay/10/2007/ H3N2 and 42% to B/Brisbane/60/2008. At 1 year, the factor increase of GMT was 1.8 to the two influenza A strains.

Conclusion

Two doses of adjuvanted influenza vaccine improved the SCR and the SPR among HIV-infected subjects. Long-term follow-up indicates revaccination in the next influenza season whether they received an adjuvanted or non-adjuvanted influenza vaccine.

Influence of corticosteroid therapy on the serum antibody response to influenza vaccine in elderly patients with chronic pulmonary diseases

Annual influenza vaccination is strongly recommended for patients with chronic pulmonary diseases, such as bronchial asthma, chronic obstructive pulmonary disease (COPD), and interstitial pulmonary diseases. However, many of these patients regularly receive systemic and/or inhaled corticosteroid therapy, and the impact of corticosteroid therapy on influenza vaccine efficacy and safety is unclear. Patients with chronic pulmonary diseases were enrolled in the study and divided into three groups based on their maintenance therapy: (A) without corticosteroid therapy (17 males, three females; mean age, 72.3 ± 7.9), (B) oral corticosteroid therapy (four males, seven females; mean age, 66.1 ± 10.6), and (C) inhaled corticosteroid therapy (eight males, nine females; mean age, 62.4 ± 16.0). All patients received influenza vaccine, and serum hemagglutination inhibition (HI) antibodies against influenza strains A/H1N1, A/H3N2, and B were measured at baseline (before vaccination) and 4-6 weeks after vaccination. Sufficient antibody titers or significant increases were observed after vaccination compared with titers before vaccination in all three groups. No systemic reactions were reported. Long-term oral/inhaled corticosteroid therapy was not associated with vaccination side effects and did not affect the immune response to the influenza vaccine.

Additive preventive effect of influenza and pneumococcal vaccines in the elderly: results of a large cohort study

Elderly people are at increased risk of influenza and pneumococcal diseases. Influenza increases clinical pneumococcal disease incidence. Pneumococcal vaccination could therefore be a supplement to influenza vaccination. This study evaluated all-cause mortality and antibiotic consumption according to elderly people's influenza and pneumococcal vaccination status. Its goal was to demonstrate that vaccination with both Influenza and pneumococcal vaccines decrease all-cause mortality and antibiotic consumption. From 2004-10-01 to 2004-12-31 (3 mo), elderly people (≥ 65 y) who lived in the Gard department (South of France) were offered both vaccinations. Among the 68,897 subjects followed-up one year after this vaccination campaign, 21,303 (30.9%) were vaccinated with both vaccines, 18,651 (27.1%) with influenza vaccine alone, 3,769 (5.5%) with pneumococcal vaccine alone; 25,174 (36.5%) subjects were unvaccinated. Mortality rate (per 1,000 inhabitants-year) adjusted on gender, age and prior underlying chronic disease was 17.9 (95% CI: 16.3-19.6), 20.8 (19.0-22.8), 22.5 (19.0-26.6) and 24.7 (22.7-26.8), respectively. It was 42.1 (38.8-45.8) in elderly people with underlying chronic disease who received both vaccines vs. 58.1 (53.7-62.9) in unvaccinated elderly people. The decrease in mortality rate was 27.0% (20.0-34.0) in subjects who received both vaccines and 16.0% (6.0-24.0) in those who received influenza vaccine. No significant reduction in mortality rate was seen with the pneumococcal vaccine alone. Influenza and/or pneumococcal vaccinations did not decrease antibiotic consumption that drastically increases during the winter period. An additive effect was observed in the prevention of all-cause mortality with influenza and pneumococcal vaccines given together in elderly people, including in those with underlying chronic disease.

Knowledge, attitudes, and practices of school personnel regarding influenza, vaccinations, and school outbreaks

BACKGROUND

School personnel are important for communicating with parents about school vaccination programs and recognizing influenza outbreaks. This study examined knowledge, attitudes, and practices of school personnel regarding seasonal and 2009 H1N1 influenza, vaccinations, and school outbreak investigations.

METHODS

Data were analyzed from survey interviews of 58 elementary and middle school personnel in 2010.

RESULTS

Principals, assistant principals, and nurses have higher knowledge than front office clerks regarding seasonal (odds ratio [OR]: 2.50, 95% confidence interval [CI]: 1.15-5.42) and 2009 H1N1 influenza (OR: 2.04, 95% CI: 1.19-3.71). During 2009-2010, 63.8 and 19.0% of school personnel received seasonal and 2009 H1N1 influenza vaccine, respectively. Personnel were more likely to be vaccinated against seasonal influenza if they believed the vaccine was safe (OR: 2.26, 95% CI: 1.21-4.19). Of those unvaccinated against 2009 H1N1, 48.9% also cited safety concerns. While every principal, assistant principal, and nurse received both infectious diseases and outbreak trainings, only 42.5 and 27.5% of clerks received these trainings, respectively (p < .001), and 30% of clerks believed outbreak recognition was not their responsibility.

CONCLUSION

The level of knowledge regarding influenza illness, vaccination, and outbreaks among subjects was low overall. Education of school personnel may improve school vaccination programs and control of influenza outbreaks.

The effect of physicians' awareness on influenza and pneumococcal vaccination rates and correlates of vaccination in patients with diabetes in Turkey: an epidemiological Study "diaVAX"

We aimed to examine the effect of increased physician awareness on the rate and determinants of influenza and pneumococcal vaccinations in diabetic patients. Diabetic patients (n = 5682, mean [SD] age: 57.3 [11.6] years, 57% female) were enrolled by 44 physicians between Sept 2010 and Jan 2011. The physicians were initially questioned regarding vaccination practices, and then, they attended a training program. During the last five years, the physicians recommended influenza and pneumococcal vaccinations to 87.9% and 83.4% of the patients, respectively; however; only 27% of the patients received the influenza and 9.8% received the pneumococcal vaccines. One year after the training, the vaccination rates increased to 63.3% and 40.7%, respectively. The logistic regression models revealed that variables which increased the likelihood of having been vaccinated against influenza were: longer duration of diabetes, presence of hyperlipidemia and more use of concomitant medications whereas more use of anti-hyperglycemic medications was associated with increased odds of vaccination. On the other hand, older age, longer duration of diabetes and presence of a cardiovascular disease were variables which decreased the likelihood of having been vaccinated against pneumococcal disease during the past five years. However, during the study period, variables which decreased the odds of having been vaccinated included: older age and anti-hyperglycemic medications for influenza, and presence of hyperlipidemia and a family history of hypertension for pneumococcal disease. While variables which increased the likelihood of vaccination in the same period were: increased number of co-morbidities for influenza, and family history of diabetes for pneumococcal disease. We conclude that increased awareness of physicians may help improve vaccination rates against influenza and pneumococcal disease. However, diabetic patients with more severe health conditions are less likely to having been vaccinated. More structural/systematic vaccination programs are needed to increase the vaccination rates in patients with diabetes.

Immunogenicity and safety of an inactivated quadrivalent influenza vaccine candidate: a phase III randomized controlled trial in children

BACKGROUND

Mismatch between circulating influenza B viruses (Yamagata and Victoria lineages) and vaccine strains occurs frequently.

METHODS

In a randomized controlled trial, immunogenicity and safety of an inactivated quadrivalent influenza vaccine candidate (QIV) versus trivalent inactivated influenza vaccine (TIV)-Victoria(Vic) and TIV-Yamagata(Yam) in children 3-17 years of age was evaluated. In an open-label study arm, QIV only was assessed in children 6-35 months of age.

RESULTS

A total of 3094 children (932 QIV, 929 TIV-Vic, 932 TIV-Yam, and 301 QIV only) were vaccinated. QIV was noninferior to the TIVs for shared strains (A/H3N2 and A/H1N1) based on hemagglutination-inhibition (HI) antibodies 28 days after last vaccination, and superior for the unique B strains Victoria and Yamagata (geometric mean titer ratios 2.61, 3.78; seroconversion rate differences 33.96%, 44.63%). Among children in the randomized trial, adverse event rates were similar except for injection site pain (dose 1: 65.4% QIV, 54.6% TIV-Vic, 55.7% TIV-Yam).

CONCLUSION

QIV elicited superior HI responses to the added B strains compared to TIV controls, potentially improving its effectiveness against influenza B. HI responses were similar between QIV and TIV controls for the shared strains. QIV had an acceptable safety profile relative to TIVs.

CLINICAL TRIALS REGISTRATION

NCT01198756.

Success of the 4 pillars toolkit for influenza and pneumococcal vaccination in adults

BACKGROUND

Standing order programs (SOPs) allowing nonphysician personnel to assess patients' immunization status and administer vaccines without an individual physician order are a proven method of increasing adult vaccinations, yet they are underutilized by primary care physicians.

METHODS

In a before-and-after trial, a pilot-tested and revised SOP toolkit (4 Pillars Toolkit) was implemented in four diverse primary care practices. Changes in influenza and pneumococcal polysaccharide vaccine (PPSV) vaccination rates were measured. The toolkit was evaluated using direct observation, group interviews, and surveys of each practice's staff.

RESULTS

Use of the 4 Pillars Toolkit varied across sites. PPSV rates increased significantly overall for high-risk adults (18-64 years; 25% in 2010-2011 vs. 40% in 2011-2012, p = .02) but not for older adults (≥65 years; 44% vs. 52%, p = .26) and in two of four practices among both high-risk and older adults (p < .05). Influenza vaccination rates increased significantly in three of four sites and overall (22% in 2010-2011 vs. 33% in 2011-2012, overall; p < .001). Practices more fully implementing the toolkit demonstrated larger increases in vaccination rates.

CONCLUSIONS

The 4 Pillars Toolkit is a promising means of improving primary care practice across diverse settings, with better results observed when strategies were maximally utilized.

Influenza diagnosis and vaccination in Poland

In Poland between several thousand and several million cases of influenza and suspected influenza cases are registered, depending on the epidemic season. A variety of methods are available for the detection of the influenza viruses responsible for respiratory infection starting with the isolation of the virus in chick embryos or in cell lines such as MDCK, VERO, etc., and finishing with a variety of modifications of the classical PCR molecular biology such as PCR multiplex and Real-Time. The most effective way to combat influenza is through vaccination. Regular vaccination is one of the few steps that may be taken to protect individuals, especially in high-risk groups, from the potential and serious complications of influenza. In many countries, including Poland, despite the recommendations, the rate of vaccination against influenza is still low in all age groups. In the epidemic season 2011/2012, the level of distribution of the seasonal influenza vaccines was 4.5% of the population.

Effectiveness of influenza vaccine for preventing laboratory-confirmed influenza hospitalizations in adults, 2011-2012 influenza season

During the 2011-2012 influenza season, we enrolled hospitalized adults with acute respiratory illness and tested each for influenza using reverse transcription polymerase chain reaction. Influenza vaccination was verified in 35% (6/17) of adults with influenza-associated hospitalizations compared to 64% (97/152) of test-negative controls; adjusted vaccine effectiveness was 71.4% (95% confidence interval, 17.1%-94.9%).

Intranasal influenza vaccination using a new synthetic mucosal adjuvant SF-10: induction of potent local and systemic immunity with balanced Th1 and Th2 responses

BACKGROUND

We found previously that bovine pulmonary Surfacten® used in newborns with acute respiratory distress syndrome is a safe and efficacious antigen vehicle for intranasal vaccination.

OBJECTIVES

The objective of this study was to industrially produce a synthetic adjuvant mimicking Surfacten® for clinical use without risk of bovine spongiform encephalopathy.

METHODS

We selected three Surfacten lipids and surfactant protein (SP)-C as essential constituents for adjuvanticity. For replacement of the hydrophobic SP-C, we synthesized SP-related peptides and analyzed their adjuvanticity. We evaluated lyophilization to replace sonication for the binding of influenza virus hemagglutinin (HA) to the synthetic adjuvant. We also added a carboxy vinyl polymer (CVP) to the synthetic adjuvant and named the mixture as SF-10 adjuvant. HA combined with SF-10 was administered intranasally to mice, and induction of nasal-wash HA-specific secretory IgA (s-IgA) and serum IgG with Th1-/Th2-type cytokine responses in nasal cavity and virus challenge test were assessed.

RESULTS AND CONCLUSIONS

Intranasal immunization with HA-SF-10 induced significantly higher levels of anti-HA-specific nasal-wash s-IgA and serum IgG than those induced by HA-poly(I:C), a reported potent mucosal vaccine, and provided highly efficient protection against lethal doses of virus challenge in mice. Anti-HA-specific serum IgG levels induced by HA-SF-10 were almost equivalent to those induced by subcutaneous immunization of HA twice. Intranasal administration of HA-SF-10 induced balanced anti-HA-specific IgG1 and IgG2a in sera and IFN-γ- and IL-4-producing lymphocytes in nasal cavity without any induction of anti-HA IgE. The results suggest that HA-SF-10 is a promising nasal influenza vaccine and that SF-10 can be supplied in large quantities commercially.

Verifying influenza and pneumococcal immunization status of children in 2009-2010 from primary care practice records and from the North Carolina Immunization Registry

BACKGROUND

The North Carolina Immunization Registry (NCIR) has been available since 2004. We sought to measure its utilization among practices that provide primary care for children who are enrolled in a prospective influenza surveillance study.

METHODS

This study included children aged 0.5-17 years who presented with fever or acute respiratory symptoms to an emergency department or inpatient setting in Winston-Salem, North Carolina, from September 1, 2009, through May 19, 2010. Study team members verified influenza and pneumococcal immunization status by requesting records from each child's primary care practice and by independently reviewing the NCIR. We assessed agreement of nonregistry immunization medical records with NCIR data using the kappa statistic.

RESULTS

Fifty-six practices confirmed the immunization status of 292 study-enrolled children. For most children (238/292, 82%), practices verified the child's immunizations by providing a copy of the NCIR record. For 54 children whose practices verified their immunizations by providing practice records alone, agreement with the NCIR by the kappa statistic was 0.6-0.7 for seasonal and monovalent H1N1 influenza vaccines and 0.8-0.9 for pneumococcal conjugate and polysaccharide vaccines. A total of 221 (98%) of 226 enrolled children younger than 6 years of age had 2 or more immunizations documented in the NCIR.

LIMITATIONS

NCIR usage may vary in other regions of North Carolina.

CONCLUSION

More than 95% of children younger than 6 years of age had 2 or more immunizations documented in the NCIR; thus, the Centers for Disease Control and Prevention 2010 goal for immunization information systems was met in this population. We found substantial agreement between practice records and the NCIR for influenza and pneumococcal immunizations in children.

Characterization and optimization of bilosomes for oral vaccine delivery

Oral vaccines offer significant benefits due to the ease of administration, better patient compliance and non-invasive, needle-free administration. However, this route is marred by the harsh gastro intestinal environment which is detrimental to many vaccine formats. To address this, a range of delivery systems have been considered including bilosomes; these are bilayer vesicles constructed from non-ionic surfactants combined with the inclusion of bile salts which can stabilize the vesicles in the gastro intestinal tract by preventing membrane destabilization. The aim of this study was to investigate the effect of formulation parameters on bilosome carriers using Design of Experiments to select an appropriate formulation to assess in vivo. Bilosomes were constructed from monopalmitoylglycerol, cholesterol, dicetyl phosphate and sodium deoxycholate at different blends ratios. The optimized bilosome formulation was identified and the potential of this formulation as an oral vaccine delivery system were assessed in biodistribution and vaccine efficacy studies. Results showed that the larger bilosomes vesicles (~6 µm versus 2 µm in diameter) increased uptake within the Peyer's patches and were able to reduce median temperature differential change and promote a reduction in viral cell load in an influenza challenge study.

Safety and tolerability of a 2009 trivalent inactivated split-virion influenza vaccine in infants, children and adolescents

OBJECTIVE

To evaluate the safety of CSL's split-virion inactivated trivalent 2009 Southern Hemisphere formulation influenza vaccine (TIV) in children.

METHODS

We enrolled 1992 healthy children into three groups: Cohorts A, ≥ 6 months to <3 years; B, ≥ 3 years to <9 years; and C, ≥ 9 years to <18 years. Children received one or two doses of 0.25 ml (22.5 μg haemagglutinin) or 0.5 ml (45 μg) TIV, depending on age and prior vaccination history. We collected post-vaccination solicited adverse event (AE) data (days 0-6), including fever (temperature: ≥ 37.5°C axilla, ≥ 38.0°C oral), unsolicited AEs (days 0-29) and serious AEs (SAEs) and new-onset chronic illnesses (NOCIs; to day 180 after last vaccination).

RESULTS

At least one solicited AE was reported by 80%/78%/78% of children in Cohorts A, B and C, respectively. Systemic AEs were more common among Cohort A (72% of participants), and local AEs were more common among Cohort C (71% of participants). Fever was more common in younger cohorts, in influenza vaccine-naïve children (29% of Cohort A receiving their first dose), and following first compared with second doses. Severe fever following a first dose prevented 20 participants receiving their second scheduled vaccine dose. A 7-month-old participant had a single uncomplicated febrile convulsion on the day of vaccination.

CONCLUSIONS

Nearly 80% of subjects reported at least one solicited AE following immunization. Fever prevalence was highest in vaccine-naïve Cohort A participants, similar to other paediatric studies using CSL vaccine. Further research to understand fever-related AEs in children following CSL's TIV is recommended.

Effectiveness of vaccination with 23-valent pneumococcal polysaccharide vaccine in preventing hospitalization with laboratory confirmed influenza during the 2009-2010 and 2010-2011 seasons

BACKGROUND

Since influenza predisposes to bacterial pneumonia caused by Streptococcus pneumoniae, studies have suggested that pneumococcal vaccination might reduce its occurrence during pandemics. We assessed the effectiveness of pneumococcal polysaccharide vaccination alone and in combination with influenza vaccination in preventing influenza hospitalization during the 2009-2010 pandemic wave and 2010-2011 influenza epidemic.

RESULTS

1187 cases and 2328 controls were included. The adjusted estimate of effectiveness of pneumococcal vaccination in preventing influenza hospitalization was 41% (95% CI 8-62) in all patients and 43% (95% CI 2-78) in patients aged ≥ 65 y. The adjusted effectiveness of dual PPV23 and influenza vaccination was 81% (95% CI 65-90) in all patients and 76% (95% CI 46-90) in patients aged ≥ 65 y. The adjusted effectiveness of influenza vaccination alone was 58% (95% CI 38-72).

METHODS

We conducted a multicenter case-control study in 36 Spanish hospitals. We selected patients aged ≥ 18 y hospitalized with confirmed influenza and two hospitalized controls per case, matched according to age, date of hospitalization and province of residence. Multivariate analysis was performed using conditional logistic regression. Subjects were considered vaccinated if they had received the pneumococcal or seasonal influenza vaccine>14 d (or>7 d for pandemic influenza vaccine) before the onset of symptoms (cases) or the onset of symptoms in matched cases (controls).

CONCLUSIONS

In elderly people and adults with chronic illness, pneumococcal vaccination may reduce hospitalizations during the influenza season. In people vaccinated with both the influenza and pneumococcal vaccines, the benefit in hospitalizations avoided was greater than in those vaccinated only against influenza.

Preclinical evaluation of Vaxfectin-adjuvanted Vero cell-derived seasonal split and pandemic whole virus influenza vaccines

Increasing the potency and supply of seasonal and pandemic influenza vaccines remains an important unmet medical need which may be effectively accomplished with adjuvanted egg- or cell culture-derived vaccines. Vaxfectin, a cationic lipid-based adjuvant with a favorable safety profile in phase 1 plasmid DNA vaccines trials, was tested in combination with seasonal split, trivalent and pandemic whole virus, monovalent influenza vaccines produced in Vero cell cultures. Comparison of hemagglutination inhibition (HI) antibody titers in Vaxfectin-adjuvanted to nonadjuvanted vaccinated mice and guinea pigs revealed 3- to 20-fold increases in antibody titers against each of the trivalent influenza virus vaccine strains and 2- to 8-fold increases in antibody titers against the monovalent H5N1 influenza virus vaccine strain. With the vaccine doses tested, comparable antibody responses were induced with formulations that were freshly prepared or refrigerated at conventional 2-8°C storage conditions for up to 6 mo. Comparison of T-cell frequencies measured by interferon-gamma ELISPOT assay between groups revealed increases of between 2- to 10-fold for each of the adjuvanted trivalent strains and up to 22-fold higher with monovalent H5N1 strain. Both trivalent and monovalent vaccines were easy to formulate with Vaxfectin by simple mixing. These preclinical data support further testing of Vaxfectin-adjuvanted Vero cell culture vaccines toward clinical studies designed to assess safety and immunogenicity of these vaccines in humans.

The burden of influenza in young children, 2004-2009

OBJECTIVE

To characterize the health care burden of influenza from 2004 through 2009, years when influenza vaccine recommendations were expanded to all children aged ≥6 months.

METHODS

Population-based surveillance for laboratory-confirmed influenza was performed among children aged <5 years presenting with fever and/or acute respiratory illness to inpatient and outpatient settings during 5 influenza seasons in 3 US counties. Enrolled children had nasal/throat swabs tested for influenza by reverse transcriptase-polymerase chain reaction and their medical records reviewed. Rates of influenza hospitalizations per 1000 population and proportions of outpatients (emergency department and clinic) with influenza were computed.

RESULTS

The study population comprised 2970, 2698, and 2920 children from inpatient, emergency department, and clinic settings, respectively. The single-season influenza hospitalization rates were 0.4 to 1.0 per 1000 children aged <5 years and highest for infants <6 months. The proportion of outpatient children with influenza ranged from 10% to 25% annually. Among children hospitalized with influenza, 58% had physician-ordered influenza testing, 35% had discharge diagnoses of influenza, and 2% received antiviral medication. Among outpatients with influenza, 7% were tested for influenza, 7% were diagnosed with influenza, and <1% had antiviral treatment. Throughout the 5 study seasons, <45% of influenza-negative children ≥6 months were fully vaccinated against influenza.

CONCLUSIONS

Despite expanded vaccination recommendations, many children are insufficiently vaccinated, and substantial influenza burden remains. Antiviral use was low. Future studies need to evaluate trends in use of vaccine and antiviral agents and their impact on disease burden and identify strategies to prevent influenza in young infants.

High proportions of regulatory B and T cells are associated with decreased cellular responses to pH1N1 influenza vaccine in HIV-infected children and youth (IMPAACT P1088)

HIV-infected individuals have poor responses to inactivated influenza vaccines. To evaluate the potential role of regulatory T (Treg) and B cells (Breg), we analyzed their correlation with humoral and cell-mediated immune (CMI) responses to pandemic influenza (pH1N1) monovalent vaccine in HIV-infected children and youth. Seventy-four HIV-infected, 4- to 25-y old participants in a 2-dose pH1N1 vaccine study had circulating and pH1N1-stimulated Treg and Breg measured by flow cytometry at baseline, post-dose 1 and post-dose 2. Concomitantly, CMI was measured by ELISPOT and flow cytometry; and antibodies by hemagglutination inhibition (HAI). At baseline, most of the participants had pH1N1-specific IFNγ ELISPOT responses, whose magnitude positively correlated with the baseline pH1N1, but not with seasonal H1N1 HAI titers. pH1N1-specific IFNγ ELISPOT responses did not change post-dose 1 and significantly decreased post-dose 2. In contrast, circulating CD4+CD25+% and CD4+FOXP3+% Treg increased after vaccination. The decrease in IFNγ ELISPOT results was marginally associated with higher pH1N1-specific CD19+FOXP3+ and CD4+TGFβ+% Breg and Treg, respectively. In contrast, increases in HAI titers post-dose 1 were associated with significantly higher circulating CD19+CD25+% post-dose 1, whereas increases in IFNγ ELISPOT results post-dose 1 were associated with higher circulating CD4+/C8+CD25+FOXP3+%. In conclusion, in HIV-infected children and youth, influenza-specific Treg and Breg may contribute to poor responses to vaccination. However, robust humoral and CMI responses to vaccination may result in increased circulating Treg and/or Breg, establishing a feed-back mechanism.

Cross-protection against drifted influenza viruses: options offered by adjuvanted and intradermal vaccines

Antigenic drift, the evolutionary mechanism of influenza viruses, results in an increased susceptibility of vaccinated subjects against circulating viruses. New vaccines able to grant a broader and cross-reactive immune response against drifted influenza variants are needed. Several strategies were explored to enhance the immunogenicity of plain vaccines: adjuvants, carriers and intradermal administration of influenza vaccine emerge as a promising options. To evaluate the ability of a MF59-adjuvanted and intradermal influenza vaccine to elicit an effective antibody response against circulating viruses presenting antigenic patterns different from those of the vaccine strains, we compared antibody responses elicited by "implemented" vaccines and conventional intramuscular trivalent inactivated vaccine against heterologous circulating influenza A viruses. Different studies, simulating different epidemiological pictures produced by the natural antigenic drift of seasonal influenza viruses, highlighted the superior cross-reactivity of the antibodies elicited by MF59 and intradermal vaccines, compared with subunit or split vaccine against heterologous viruses.

Influenza epidemiology in Italy two years after the 2009-2010 pandemic: need to improve vaccination coverage

Since 2000, a sentinel surveillance of influenza, INFLUNET, exists in Italy. It is coordinated by the Ministry of Health and is divided into two parts; one of these is coordinated by the National Institute of Health (NIH), the other by the Inter-University Centre for Research on Influenza and other Transmissible Infections (CIRI-IT). The influenza surveillance system performs its activity from the 42nd week of each year (mid-October) to the 17th week of the following year (late April). Only during the pandemic season (2009/2010) did surveillance continue uninterruptedly. Sentinel physicians - about 1,200 general practitioners and independent pediatricians - send in weekly reports of cases of influenza-like illness (ILI) among their patients (over 2% of the population of Italy) to these centers.   In order to estimate the burden of pandemic and seasonal influenza, we examined the epidemiological data collected over the last 3 seasons (2009-2012). On the basis of the incidences of ILIs at different ages, we estimated that: 4,882,415; 5,519,917; and 4,660,601 cases occurred in Italy in 2009-2010, 2010-2011 and 2011-2012, respectively. Considering the ILIs, the most part of cases occurred in < 14 y old subjects and especially in 5-14 y old individuals, about 30% and 21% of cases respectively during 2009-2010 and 2010-2011 influenza seasons. In 2011-2012, our evaluation was of about 4.7 million of cases, and as in the previous season, the peak of cases regarded subjects < 14 y (about 29%). A/California/07/09 predominated in 2009-2010 and continued to circulate in 2010-2011. During 2010-2011 B/Brisbane/60/08 like viruses circulated and A/H3N2 influenza type was sporadically present. H3N2 (A/Perth/16/2009 and A/Victoria/361/2011) was the predominant influenza type-A virus that caused illness in the 2011-2012 season. Many strains of influenza viruses were present in the epidemiological scenario in 2009-2012. In the period 2009-2012, overall vaccination coverage was low, never exceeding 20% of the Italian population. Among the elderly, coverage rates grew from 40% in 1999 to almost 70% in 2005-2006, but subsequently decreased, in spite of the pandemic; this trend reveals a slight, though constant, decline in compliance with vaccination. Our data confirm that 2009 pandemics had had a spread particularly important in infants and schoolchildren, and this fact supports the strategy to vaccinate schoolchildren at least until 14 y of age. Furthermore, the low levels of vaccination coverage in Italy reveal the need to improve the catch-up of at-risk subjects during annual influenza vaccination campaigns, and, if possible, to extend free vaccination to at least all 50-64-y-old subjects. Virologic and epidemiological surveillance remains critical for detection of evolving influenza viruses and to monitor the health and economic burden in all age class annually.

Immunogenicity of influenza H1N1 vaccination in mixed connective tissue disease: effect of disease and therapy

OBJECTIVE

To assess the potential acute effects regarding the immunogenicity and safety of non-adjuvanted influenza A H1N1/2009 vaccine in patients with mixed connective tissue disease and healthy controls.

METHODS

Sixty-nine mixed connective tissue disease patients that were confirmed by Kasukawa's classification criteria and 69 age- and gender-matched controls participated in the study; the participants were vaccinated with the non-adjuvanted influenza A/California/7/2009 (H1N1) virus-like strain. The percentages of seroprotection, seroconversion, geometric mean titer and factor increase in the geometric mean titer were calculated. The patients were clinically evaluated, and blood samples were collected pre- and 21 days post-vaccination to evaluate C-reactive protein, muscle enzymes and autoantibodies. Anti-H1N1 titers were determined using an influenza hemagglutination inhibition assay. ClinicalTrials.gov: NCT01151644.

RESULTS

Before vaccination, no difference was observed regarding the seroprotection rates (p = 1.0) and geometric mean titer (p = 0.83) between the patients and controls. After vaccination, seroprotection (75.4% vs. 71%, (p = 0.7), seroconversion (68.1% vs. 65.2%, (p = 1.00) and factor increase in the geometric mean titer (10.0 vs. 8.0, p = 0.40) were similar in the two groups. Further evaluation of seroconversion in patients with and without current or previous history of muscle disease (p = 0.20), skin ulcers (p = 0.48), lupus-like cutaneous disease (p = 0.74), secondary Sjogren syndrome (p = 0.78), scleroderma-pattern in the nailfold capillaroscopy (p = 1.0), lymphopenia #1000/mm³ on two or more occasions (p = 1.0), hypergammaglobulinemia $1.6 g/d (p = 0.60), pulmonary hypertension (p = 1.0) and pulmonary fibrosis (p = 0.80) revealed comparable rates. Seroconversion rates were also similar in patients with and without immunosuppressants. Disease parameters, such as C-reactive protein (p = 0.94), aldolase (p = 0.73), creatine phosphokinase (p = 0.40) and ribonucleoprotein antibody levels (p = 0.98), remained largely unchanged pre and post-vaccination. No severe side effects were reported.

CONCLUSIONS

The non-adjuvanted influenza A/H1N1 vaccination immune response in mixed connective tissue disease patients is adequate and does not depend on the disease manifestations and therapy.

Influenza vaccines licensed in the United States in healthy children: a systematic review and network meta-analysis (Protocol)

BACKGROUND

Influenza is an acute respiratory illness caused by influenza viruses, which occurs in epidemics worldwide every year. Children are an important target for prevention methods, including vaccination. While evidence about the decision on whether to vaccinate healthy children is robust, evidence supporting the decision of which of available vaccines to use remains unclear.This review will summarize the evidence about the efficacy and safety of the available vaccines for seasonal influenza licensed in the United States for use in healthy children.

METHODS/DESIGN

An umbrella systematic review (SR) and network meta-analysis will be conducted of randomized controlled trials (RCTs). We will search for SRs to identify parallel RCTs evaluating inactive and/or live attenuated influenza vaccines licensed in the United States for use in healthy children to prevent influenza. Subsequently, we will update the literature search of the selected SRs to the present time to capture recent controlled studies. To complement the work focused on harms, we will also select observational studies focusing on post marketing retrospective studies. Inclusion will not be limited by language, publication date or publication status. To identify additional candidate studies, we will review the reference lists of the eligible primary studies and narrative reviews; we will query the expert members of the Advisory Committee on Immunization Practices and review references from their previous statement. Additionally, we will review the reports from the Institute of Medicine on the adverse effects of vaccines. Two reviewers will independently determine study eligibility and will extract descriptive, methodological (using the Cochrane risk of bias tool for RCTs and the Newcastle-Ottawa scale for observational studies) and efficacy data. When possible, we will conduct meta-analyses and network meta-analyses by combining indirect and direct comparisons.We will evaluate heterogeneity using the I2 statistic and the agreement of indirect comparisons and direct evidence. We will report the Cochrane Q test to determine the statistical significance of heterogeneity.The overall quality of evidence will be assessed following the GRADE (Grading of Recommendation, Assessment, Development and Evaluation) approach.

DISCUSSION

Our systematic review will allow patients, clinicians, guideline developers and policy makers to make evidence-based choices between the two available vaccine options, by providing information regarding benefits and harms of these types of vaccines.

The rate of seasonal influenza vaccination in diabetic children, the effect of recommendation and the factors influencing the acceptance of recommendation: an interventional study

OBJECTIVE

To investigate the vaccination rate of influenza in diabetic children and the effect of recommendation and other factors on vaccination rate.

MATERIAL AND METHODS

On July 2011, 144 diabetic children and their families were informed about and were recommended to receive the influenza vaccine every year, in September. On December 2011, parents were questioned about the vaccination.

RESULTS

Influenza vaccination rate of the previous season (28.3%) increased to 50.0% (p<0.05). Receiving the vaccine in 2010 was the only contributing factor to the recommendation success. The reasons given by the non-receivers were; forgetting (50.0%), fear of adverse-effects (26.4%), not believing in usefulness (15.2%), rejection by the child (4.2%) and effects of media (4.2%). 88.9% of those who forgot declared that they would receive if they were reminded at the beginning of the season.

CONCLUSION

The rate of influenza vaccination was low. The majority of those who didn't recieve the vaccination declared that they would if they were reminded at the beginning of the season and the fact that "receiving the vaccine in 2010" was the only factor influencing the recommendation success indicate that recommending isn't enough but that reminding and giving detailed information about the vaccine will increase vaccination rates independent of other factors.

Pneumonia immunization in older adults: review of vaccine effectiveness and strategies

Vaccination remains the primary preventive strategy in the elderly against Streptococcus pneumoniae and influenza infections. The effectiveness of this strategy in preventing pneumonia has been in doubt despite the increase in vaccination coverage among older adults. Randomized controlled trials (RCTs) and observational studies aimed at determining clinical outcomes and immune response following pneumococcal vaccination have yielded conflicting results. The protective efficacy of pneumococcal vaccination against pneumonia in older adults has not been firmly established due to a lack of RCTs specifically examining patients ≥ 65 years of age. Similarly, the reported benefits of influenza vaccination have been derived from observational data. The assessment of clinical benefit from influenza vaccination in the elderly population is complicated by varying cohorts, virulence of the influenza strain, and matching of vaccine and circulating viral strains. The presence of selection bias and use of nonspecific end points in these studies make the current evidence inconclusive in terms of overall benefit. The development of more immunogenic vaccines through new formulations or addition of adjuvants holds the promise of revolutionizing delivery and improving efficacy. Dismantling existing barriers through education, providing technology assistance predominantly to developing countries, and establishing clear regulatory guidance on pathways for approval are necessary to ensure timely production and equitable distribution.

Moderate influenza vaccine effectiveness with variable effectiveness by match between circulating and vaccine strains in Australian adults aged 20-64 years, 2007-2011

Please cite this paper as: Kelly et al. Moderate influenza vaccine effectiveness with variable effectiveness by match between circulating and vaccine strains in Australian adults aged 20–64 years, 2007–2011. Influenza and Other Respiratory Viruses DOI:10.1111/irv.12018.

Background  Influenza vaccines are licensed annually based on immunogenicity studies. We used five sequential years of data to estimate influenza vaccine effectiveness (VE), the critical outcome in the field.

Methods  Between 2007 and 2011, we performed annual prospective test‐negative design case–control studies among adults aged 20–64 years recruited from sentinel general practices in the Australian state of Victoria. We used PCR‐confirmed influenza as the endpoint to estimate influenza VE for all years. We compared annual VE estimates with the match between circulating and vaccine strains, determined by haemagglutination inhibition assays.

Results  The adjusted VE estimate for all years (excluding 2009) was 62% (95% CI 43, 75). By type and subtype, the point estimates of VE by year ranged between 31% for seasonal influenza A(H1N1) and 88% for influenza A(H1N1)pdm09. In 2007, when circulating strains were assessed as incompletely matched, the point estimate of the adjusted VE against all influenza was 58%. The point estimate was 59% in 2011 when all strains were assessed as well matched.

Conclusion  Trivalent inactivated vaccines provided moderate protection against laboratory‐confirmed influenza in adults of working age, although VE estimates were sensitive to the model used. VE estimates correlated poorly with circulating strain match, as assessed by haemagglutination inhibition assays, suggesting a need for VE studies that incorporate antigenic characterization data.

Efficacy of influenza vaccine among elderly patients by physical activity status

OBJECTIVE

Although many studies have shown the usefulness of influenza vaccine in elderly in-patients, the efficacy of vaccination with regard to the daily physical activities of patients has not been fully evaluated. To address this issue, we correlated the use of medical resources with vaccination status in patients categorized according to their daily activity levels.

METHODS

The subjects comprised 237 in-patients at or above 51 years of age, who were hospitalized in the long-term care unit of a Japanese hospital between January and March, 1999. The vaccination status and medical resources use (i.e., oral antibiotics, injected antibiotics, blood cell count, chest X-ray) of each patient were recorded, and the patients were assigned to three subgroups, based on daily life activity scores.

RESULTS

Vaccinated in-patients in the 'bed-bound' category required fewer medical resources, i.e., oral antibiotics (-2.29 days,P<0.05), injected antibiotics (-5.02 days,P<0.001), blood cell counts (-4.66 times,P<0.001), and chest X-rays (-4.31 times,P<0.001), compared with unvaccinated in-patients. There were no significant differences in treatment parameters between vaccinated and unvaccinated patients in the 'partly limited' or 'no limitation' categories.

CONCLUSIONS

It is suggested that influenza vaccination significantly reduces the need for medical treatment only among those in-patients who are the least physically active. Further studies are required to replicate these findings, and to elucidate the underlying reasons for this reduction.

Focusing on flu: Parent perspectives on school-located immunization programs for influenza vaccine

School-located immunization programs (SLIP) will only be successful if parents consent to their children's participation. It is critical to understand parent perspectives regarding the factors that make them more or less likely to provide that consent. Organizations creating SLIPs will be able to capitalize on the aspects of SLIPs that parents appreciate, and address and correct issues that may give rise to parent concerns. This study involved five focus groups among the parents of school students in a large, urban school district. Findings highlight the broad range of concepts important to parents when considering participation in a SLIP. The safety and trust issues regarding vaccines in general that are so important to parents are also important to parents when considering participation in a SLIP. Effective communication strategies that include assurances regarding tracking of information and the competence and experience of immunizers will be helpful when addressing parents regarding SLIPs. In addition, parents were very cognizant of and positive regarding the public health benefits associated with SLIPs. Further study among larger populations of parents will further refine these ideas and aid in the development of successful influenza vaccine SLIPs that directly address and communicate with parents about the issues most important to them.

Comparison of VAERS fetal-loss reports during three consecutive influenza seasons: was there a synergistic fetal toxicity associated with the two-vaccine 2009/2010 season?

The aim of this study was to compare the number of inactivated-influenza vaccine–related spontaneous abortion and stillbirth (SB) reports in the Vaccine Adverse Event Reporting System (VAERS) database during three consecutive flu seasons beginning 2008/2009 and assess the relative fetal death reports associated with the two-vaccine 2009/2010 season. The VAERS database was searched for reports of fetal demise following administration of the influenza vaccine/vaccines to pregnant women. Utilization of an independent surveillance survey and VAERS, two-source capture–recapture analysis estimated the reporting completeness in the 2009/2010 flu season. Capture–recapture demonstrated that the VAERS database captured about 13.2% of the total 1321 (95% confidence interval (CI): 815–2795) estimated reports, yielding an ascertainment-corrected rate of 590 fetal-loss reports per million pregnant women vaccinated (or 1 per 1695). The unadjusted fetal-loss report rates for the three consecutive influenza seasons beginning 2008/2009 were 6.8 (95% CI: 0.1–13.1), 77.8 (95% CI: 66.3–89.4), and 12.6 (95% CI: 7.2–18.0) cases per million pregnant women vaccinated, respectively. The observed reporting bias was too low to explain the magnitude increase in fetal-demise reporting rates in the VAERS database relative to the reported annual trends. Thus, a synergistic fetal toxicity likely resulted from the administration of both the pandemic (A-H1N1) and seasonal influenza vaccines during the 2009/2010 season.

Persistence of influenza vaccine-induced antibody in lung transplant patients and healthy individuals beyond the season

BACKGROUND

The timing of influenza vaccination and susceptibility to re-circulating virus in the population is influenced by the persistence of seroprotection. Immunosuppressed transplant patients are known to have lower antibody response rates than healthy individuals, but acceptable antibody concentrations are achieved. The duration of this seroprotection beyond a single season has not been evaluated in either healthy or immunosuppressed populations.

METHODS

Influenza antibody concentrations against viruses no longer included in the vaccine were measured in serum by hemagglutination inhibition assay annually following vaccination of 73 lung transplant participants and 27 healthy controls. Seroprotection was defined as a titer of ≥ 1:40 and was compared between groups over the measured term using Fisher's exact tests.

RESULTS

Seroprotection rates for influenza A and B strains at one year following immunization were 100% for lung transplant and healthy controls. Rates at two years for the influenza A strains were 65-74% for lung transplant vs. 77-100% in healthy controls. Rates for influenza B strains two years following immunization were 27-50% for lung transplant vs. 16-38% in healthy controls. (Fisher's exact test; not significant for between group comparisons; p < 0.05 for between season comparisons)

CONCLUSIONS

Vaccine-induced antibody persistence appears to be influenced more by the vaccine virus strain than the immune status of the vaccinated individuals. Seroprotection rates are high 12 mo following influenza vaccination but wane over the second year, particularly for influenza B viruses. Annual influenza immunization is indicated, even for healthy individuals and even when the vaccine viruses do not change.

Ki-67 expression reveals strong, transient influenza specific CD4 T cell responses after adult vaccination

Although previous studies have found minimal changes in CD4 T cell responses after vaccination of adults with trivalent inactivated influenza vaccine, daily sampling and monitoring of the proliferation marker Ki-67 have now been used to reveal that a substantial fraction of influenza-specific CD4 T cells respond to vaccination. At 4-6 days after vaccination, there is a sharp rise in the numbers of Ki-67-expressing PBMC that produce IFNγ, IL-2 and/or TNFα in vitro in response to influenza vaccine or peptide. Ki-67(+) cell numbers then decline rapidly, and 10 days after vaccination, both Ki-67(+) and overall influenza-specific cell numbers are similar to pre-vaccination levels. These results provide a tool for assessing the quality and quantity of CD4 T cell responses to different influenza vaccines, and raise the possibility that the anti-influenza T cell memory response may be qualitatively altered by vaccination, even if the overall memory cell numbers do not change significantly.

The potential economic value of a 'universal' (multi-year) influenza vaccine

BACKGROUND

Limitations of the current annual influenza vaccine have led to ongoing efforts to develop a 'universal' influenza vaccine, i.e., one that targets a ubiquitous portion of the influenza virus so that the coverage of a single vaccination can persist for multiple years.

OBJECTIVES

To estimate the economic value of a 'universal' influenza vaccine compared to the standard annual influenza vaccine, starting vaccination in the pediatric population (2-18 year olds), over the course of their lifetime.

PATIENT/METHODS

Monte Carlo decision analytic computer simulation model.

RESULTS

Universal vaccine dominates (i.e., less costly and more effective) the annual vaccine when the universal vaccine cost ≤ $100/dose and efficacy ≥ 75% for both the 5- and 10-year duration. The universal vaccine is also dominant when efficacy is ≥ 50% and protects for 10 years. A $200 universal vaccine was only cost-effective when ≥ 75% efficacious for a 5-year duration when annual compliance was 25% and for a 10-year duration for all annual compliance rates. A universal vaccine is not cost-effective when it cost $200 and when its efficacy is ≤ 50%. The cost-effectiveness of the universal vaccine increases with the duration of protection.

CONCLUSIONS

Although development of a universal vaccine requires surmounting scientific hurdles, our results delineate the circumstances under which such a vaccine would be a cost-effective alternative to the annual influenza vaccine.

Standing orders for influenza and pneumococcal polysaccharide vaccination: correlates identified in a national survey of U.S. Primary care physicians

BACKGROUND

Standing orders programs (SOPs) allow non-physician medical staff to assess eligibility and administer vaccines without a specific physician's order. SOPs increase vaccination rates but are underutilized.

METHOD

In 2009, correlates of SOPs use for influenza vaccine and pneumococcal polysaccharide vaccination (PPV) were assessed in a nationally representative, stratified random sample of U.S. physicians (n = 880) in family and internal medicine who provided office immunization. The response rate was 67%. Physicians reporting no SOPs, only influenza SOPs, and joint influenza and PPV SOPs were compared using multinomial and logistic regression models to examine individual and practice-level correlates.

RESULTS

23% reported using SOPs consistently for both influenza vaccine and PPV, and 20% for influenza vaccination only, with the remainder not using SOPs. Practice-level factors that distinguished practices with joint influenza-PPV SOPs included perceived practice openness to change, strong practice teamwork, access to an electronic medical record, presence of an immunization champion in the practice, and access to nurse/physician assistant staff as opposed to medical assistants alone.

DISCUSSION

Physicians in practices with SOPs for both vaccines reported greater awareness of ACIP recommendations and/or Medicare regulations and were more likely to agree that SOPs are an effective way to boost vaccination coverage. However, implementation of both influenza and PPV SOPs was also associated with a variety of practice-level factors, including teamwork, the presence of an immunization champion, and greater availability of clinical assistants with advanced training.

CONCLUSIONS

Practice-level factors are critical for the adoption of more complex SOPs, such as joint SOPs for influenza and PPV.

Multicomponent interventions to enhance influenza vaccine delivery to adolescents

OBJECTIVE

To compare school- versus provider-based approaches to improving influenza vaccination coverage among adolescents in rural Georgia.

METHODS

We used a nonrandomized, 3-armed design: (1) a middle- and high school-based influenza vaccination intervention in 1 county; (2) a provider-based influenza vaccination intervention in a second county; and (3) a standard-of-care condition in a third county. Interventions also included distribution of an educational brochure, school presentations, and community-based outreach to enhance vaccine knowledge and awareness among adolescents and their parents.

RESULTS

During the 2008-2009 influenza season, 70 (19%) of 370 students were vaccinated in the school-based county and 110 (15%) of 736 students were vaccinated in the provider-based county, compared with 71 (8%) of 889 students in the standard-of-care county (risk ratio [RR](school): 2.4 [95% confidence interval (CI): 1.7-3.2]; RR(provider): 1.9 [95% CI: 1.4-2.5]). During 2009-2010, seasonal influenza vaccination coverage was 114 (30.4%) of 375 of students in the school-based county, 122 (16.9%) of 663 of students in the provider-based county, and 131 (15.2%) of 861 students in the standard-of-care county (RR(school): 2.3 [95% CI: 1.9-2.9]; RR(provider): 1.2 [95% CI: 0.97-1.5]).

CONCLUSIONS

Special efforts to promote influenza vaccination among rural, predominantly black students were associated with increased vaccination coverage. The school-based influenza vaccination intervention was associated with the highest levels of vaccination coverage. This study revealed the efficacy of school-based influenza education to improve vaccination rates among adolescents.

Phylogenetic Comparison of Influenza Virus Isolates from Three Medical Centers in Tehran with the Vaccine Strains during 2008-2009

BACKGROUND

Influenza virus is a major infectious pathogen of the respiratory system causing a high degree of morbidity and mortality annually. The worldwide vaccines are decided and produced annually by World Health Organization and licensed companies based on the samples collected from all over the world. The aim of this study was to determine phylogenecity and heterogenecity of the circulating influenza isolates during 2008-2009 outbreaks in Tehran, compare them with the vaccine strains that were recommended by WHO for the same period.

METHODS

Nasopharyngeal swabs (n=142) were collected from patients with influenza and influenza-like illness. Typing and subtyping of the isolates were performed using multiplex RT-PCR and phylogenetic analysis was carried out for hemagglutinin genes of the isolates.

RESULTS

Fifty out of 142 samples were positive for influenza A virus, and no influenza B virus was detected. Phylogenetic analyses revealed that the A/H1N1 isolates were related closely to A/Brisbane/59/2007, and the A/H3N2 isolates were close to A/Brisbane/10/2007 vaccine strains.

CONCLUSION

The findings of the present study demonstrate that the A/H1N1 was the predominant subtype of human influenza virus among the patients studied in Tehran during 2008-2009 winter seasons. In addition, some amino acid variation was found in Tehran/2008/H1N1 isolates from the 2008-2009 vaccine strain, but the H3N2 isolates showed higher genetic resemblance to the vaccine strain.

Delivery systems for intradermal vaccination

Intradermal (ID) vaccination can offer improved immunity and simpler logistics of delivery, but its use in medicine is limited by the need for simple, reliable methods of ID delivery. ID injection by the Mantoux technique requires special training and may not reliably target skin, but is nonetheless used currently for BCG and rabies vaccination. Scarification using a bifurcated needle was extensively used for smallpox eradication, but provides variable and inefficient delivery into the skin. Recently, ID vaccination has been simplified by introduction of a simple-to-use hollow microneedle that has been approved for ID injection of influenza vaccine in Europe. Various designs of hollow microneedles have been studied preclinically and in humans. Vaccines can also be injected into skin using needle-free devices, such as jet injection, which is receiving renewed clinical attention for ID vaccination. Projectile delivery using powder and gold particles (i.e., gene gun) have also been used clinically for ID vaccination. Building off the scarification approach, a number of preclinical studies have examined solid microneedle patches for use with vaccine coated onto metal microneedles, encapsulated within dissolving microneedles or added topically to skin after microneedle pretreatment, as well as adapting tattoo guns for ID vaccination. Finally, technologies designed to increase skin permeability in combination with a vaccine patch have been studied through the use of skin abrasion, ultrasound, electroporation, chemical enhancers, and thermal ablation. The prospects for bringing ID vaccination into more widespread clinical practice are encouraging, given the large number of technologies for ID delivery under development.

Use of standing orders for adult influenza vaccination a national survey of primary care physicians

BACKGROUND

Influenza vaccination of adults remains below recommended levels. Standing orders programs (SOPs) that allow nonphysician medical staff to assess eligibility and administer vaccines without an individualized physician's order are a proven method to increase vaccination rates. However, recent data on their use are not available.

PURPOSE

Investigators surveyed primary care physicians nationwide in 2009 to assess factors related to awareness and use of SOPs.

METHODS

Using the AMA Master List, a stratified random sample of U.S. family physicians (n=820) and general internists (n=820) was selected to receive a mailed questionnaire. The inclusion criterion was providing primary care to adults in an office-based practice. The primary outcome measure, analyzed in 2010, was consistent use of SOPs.

RESULTS

The survey response rate was 67% (1015/1517). Forty-two percent of respondents who immunized adults in their practices reported consistent use of SOPs. Those physicians differed in several dimensions, including awareness of recommendations and regulations regarding SOPs for vaccines, size and type of practice, number and level of training of clinical staff, attributes of the staff. The two variables in logistic regression models that were associated with the highest likelihood of using SOPs were awareness of recommendations to use them (OR=3.0; 95% CI=2.2, 4.1) and agreement with their effectiveness (OR=2.7, 95% CI=1.9, 3.8).

CONCLUSIONS

Fewer than half of physicians report using SOPs for influenza vaccination, a number that is not much higher than it was about a decade ago. Approaches to increase use of SOPs are needed.

Practice and child characteristics associated with influenza vaccine uptake in young children

OBJECTIVES

The objective of this study was to determine both practice and child characteristics and practice strategies associated with receipt of influenza vaccine in young children during the 2004-2005 influenza season, the first season for the universal influenza vaccination recommendation for all children who are aged 6 to 23 months.

METHODS

Clinical and demographic data from randomly selected children who were aged 6 to 23 months were obtained by chart review from a community-based cohort study in 3 US counties. The proportion of children who were vaccinated by April 5, 2005, in each practice was obtained. For assessment of practice characteristics and strategies, sampled practices received a self-administered practice survey. Practice and child characteristics that predicted complete influenza vaccination were determined by using multinomial logistic regression.

RESULTS

Forty-six (88%) of 52 sampled practices completed the survey and permitted chart reviews. Of 2384 children who were aged 6 to 23 months and were studied, 27% were completely vaccinated. The proportion of children who were completely vaccinated varied widely among practices (0%-71%). Most (87%) practices implemented ≥1 vaccination strategy. Complete influenza vaccination was associated with 3 practice characteristics: suburban location, lower patient volume, and vaccination strategies of evening/weekend vaccine clinics; with child characteristics of younger age, existing high-risk conditions, ≥6 well visits to the practice by 3 years of age, and any practice visit from October through January.

CONCLUSIONS

Modifiable factors that were associated with increased influenza vaccination coverage included October to January practice visits and evening/weekend vaccine clinics.

Predictors of reported influenza vaccination in HIV-infected women in the United States, 2006-2007 and 2007-2008 seasons

OBJECTIVE

To estimate the cumulative incidence of self-reported influenza vaccination ("vaccination coverage") and investigate predictors in HIV-infected women.

METHODS

In an ongoing cohort study of HIV-infected women in five US cities, data from two influenza seasons (2006-2007 n=1209 and 2007-2008 n=1161) were used to estimate crude and adjusted prevalence ratios (aPR) and 95% confidence intervals ([,]) from Poisson regression with robust variance models using generalized estimating equations (GEE).

RESULTS

In our study, 55% and 57% of HIV-infected women reported vaccination during the 2006-2007 and 2007-2008 seasons, respectively. Using data from both seasons, older age, non-smoking status, CD4 T-lymphocyte (CD4) count > or =200 cells/mm(3), and reporting at least one recent healthcare visit was associated with increased vaccination coverage. In the 2007-2008 season, a belief in the protection of the vaccine (aPR=1.38 [1.18, 1.61]) and influenza vaccination in the previous season (aPR=1.66 [1.44, 1.91]) most strongly predicted vaccination status.

CONCLUSION

Interventions to reach unvaccinated HIV-infected women should focus on changing beliefs about the effectiveness of influenza vaccination and target younger women, current smokers, those without recent healthcare visits, or a CD4 count <200 cells/mm(3).

The timing of influenza vaccination for older adults (65 years and older)

While studies have found influenza vaccination to be cost-effective in older adults (65 years or older), they have not looked at how the vaccine's economic value may vary with the timing of vaccine administration. We developed a set of computer simulation models to evaluate the economic impact of vaccinating older adults at different months. Our models delineated the costs and utility losses in delaying vaccination past October and suggest that policy makers and payors may consider structuring incentives (< or =$2.50 per patient) to vaccinate in October. Our results also suggest that vaccination is still cost-effective through the end of February.

Improved influenza vaccination in the skin using vaccine coated microneedles

Easy and effective vaccination methods could reduce mortality rates and morbidity due to vaccine-preventable influenza infections. In this study, we examined the use of microneedle patches to increase patient coverage through possible self-administration and enhance vaccine immunogenicity by targeted delivery to skin. We carried out a detailed study of protective immune responses after a single influenza vaccination to the skin of mice with a novel microneedle patch designed to facilitate simple and reliable vaccine delivery. Skin vaccination with inactivated virus-coated microneedles provided superior protection against lethal challenge compared to intramuscular injection as evidenced by effective virus clearance in lungs. Detailed immunologic analysis suggests that induction of virus neutralizing antibodies as well as enhanced anamnestic humoral and cellular responses contributed to improved protection by microneedle vaccination to the skin. These findings suggest that vaccination in the skin using a microneedle patch can improve protective immunity, and simplify delivery of influenza and possibly other vaccines.

Understanding adult vaccination in urban, lower-socioeconomic settings: influence of physician and prevention systems

PURPOSE

Vaccination rates for pneumococcal polysaccharide vaccine (PPV) and influenza vaccine are relatively low in disadvantaged urban populations. This study was designed to assess which physician and practice characteristics might explain differences in rates across physicians.

METHODS

PPV and influenza vaccination rates were determined for 2,021 patients aged 65 years and older receiving care from 30 physicians in 17 practices surveyed about their office systems for providing adult immunizations. Hierarchical linear modeling (HLM) analyses were used to examine the relationships among vaccination rates, patient-level characteristics, and physician variables.

RESULTS

Overall, the weighted PPV vaccination rate was 60.0% and varied widely across physicians (range, 11%-98%). At the patient level in HLM, patient race (P=.01) and age (P = .02), but not neighborhood income, were associated with PPV status. By linking physician survey data with PPV rates, we found the best pair of physician variables to be "reported time spent with patients for a well visit" (P = .01) and "use of enhanced immunization documentation" (P=.10). The overall influenza vaccination rate was 51.9% (range, 22%-96%). Patient race (P=.003) and age (P = .002) were associated with influenza vaccination. The pair of physician variables with the strongest association with influenza vaccination was "use of standing orders" (P <.001) and "average observed physician examination room time," regardless of visit type (P=.02).

CONCLUSIONS

Vaccination rates vary widely in urban settings and are associated with practice characteristics such as time spent with patients and, for influenza vaccine, use of standing orders.