Seasonal Vaccination Coverage Research Articles

Suivi en quasi-temps réel de la vaccination contre la grippe chez les 65 ans et plus en France à partir des ventes de vaccins en pharmacie

BackgroundThe aim of this study was to describe a tool based on vaccine sales to estimate vaccination coverage against seasonal influenza in near real-time in the French population aged 65 and over. MethodsVaccine sales data available on sale-day +1 came from a stratified sample of 3004 pharmacies in metropolitan France. Vaccination coverage rates were estimated between 2009 and 2014 and compared with those obtained based on vaccination refund data from the general health insurance scheme. ResultsThe seasonal vaccination coverage estimates were highly correlated with those obtained from refund data. They were also slightly higher, which can be explained by the inclusion of non-reimbursed vaccines and the consideration of all individuals aged 65 and over. We have developed an online tool that provides estimates of daily vaccination coverage during each vaccination campaign. ConclusionThe developed tool provides a reliable and near real-time estimation of vaccination coverage among people aged 65 and over. It can be used to evaluate and adjust public health messages.

Evaluation of Influenza Vaccination Efficacy: A Universal Epidemic Model

By means of a designed epidemic model, we evaluated the influence of seasonal vaccination coverage as well as a potential universal vaccine with differing efficacy on the aftermath of seasonal and pandemic influenza. The results of the modeling enabled us to conclude that, to control a seasonal influenza epidemic with a reproduction coefficient R 0 ≤ 1.5, a 35% vaccination coverage with the current seasonal influenza vaccine formulation is sufficient, provided that other epidemiology measures are regularly implemented. Increasing R 0 level of pandemic strains will obviously require stronger intervention. In addition, seasonal influenza vaccines fail to confer protection against antigenically distinct pandemic influenza strains. Therefore, the necessity of a universal influenza vaccine is clear. The model predicts that a potential universal vaccine will be able to provide sufficient reliable (90%) protection against pandemic influenza only if its efficacy is comparable with the effectiveness of modern vaccines against seasonal influenza strains (70%–80%); given that at least 40% of the population has been vaccinated in advance, ill individuals have been isolated (observed), and a quarantine has been introduced. If other antiepidemic measures are absent, a vaccination coverage of at least 80% is required.

Effectiveness of monovalent rotavirus vaccine in a high-income, predominant-use setting

Background and objectivesWe assessed monovalent rotavirus (RV1) vaccine effectiveness (VE) in a high-income setting with RV1 predominant use, and examined the burden of pediatric rotavirus gastroenteritis following the implementation of an RV1-only vaccination program. MethodsWe conducted active rotavirus gastroenteritis surveillance among children 8 weeks to <3 years of age at three hospitals. Participant information and vaccination histories were collected via parent/guardian interview and medical records. Stool specimens were tested for rotavirus; positive specimens were genotyped. The effect of increasing RV1 coverage on rotavirus prevalence was examined as a weekly time series via binomial regression with a log link function, using either categorical season or mean 2-dose rotavirus seasonal vaccine coverage as the exposure variable. As compared with RV1 vaccine formulation, rotavirus genotypes were classified as homotypic, partly-heterotypic, or heterotypic; prevalence of each was compared by season. A test-negative case-control design was used to examine RV1 VE against hospitalization or emergency visits. ResultsWe enrolled 866 participants in active surveillance; of these, 384 (44.3%) were eligible for VE analyses. After adjustment for season, we detected a 70.1% (95% CI: 21.9%, 88.6%) relative decrease in rotavirus prevalence in the 2013–14 season compared with 2012–13 season. On average, a 1% increase in ≥2-dose rotavirus coverage among children 1 year of age was associated with a 3.8% (95% CI: 1.8%, 5.8%) relative decrease in rotavirus prevalence. Rotavirus homotypic strain prevalence decreased, with 77% (95% CI: 68%, 89%) versus 8% (95% CI: 0%, 36%) prevalence during the 2011–12 and 2013–14 seasons, respectively. Adjusted 2-dose RV1 VE was 91.2% (95% CI: 61.6%, 98.0%). ConclusionsRV1 vaccine was highly effective to prevent rotavirus hospitalizations and emergency visits among children <3 years of age in a high-income setting with its predominant use. Our estimates were similar to high-income settings with concurrent RV1 and pentavalent vaccine use.

Influenza A (H1N1) 2009 monovalent and seasonal influenza vaccination among adults 25 to 64 years of age with high-risk conditions—United States, 2010

Seasonal influenza vaccination has been routinely recommended for adults with high-risk conditions. The Advisory Committee on Immunization Practices recommended that persons 25 to 64years of age with high-risk conditions be one of the initial target groups to receive H1N1 vaccination during the 2009-2010 season. We used data from the 2009-2010 Behavioral Risk Factor Surveillance System survey. Vaccination levels of H1N1 and seasonal influenza vaccination among respondents 25 to 64 years with high-risk conditions were assessed. Multivariable logistic regression models were performed to identify factors independently associated with vaccination. Overall, 24.8% of adults 25 to 64 years of age were identified to have high-risk conditions. Among adults 25 to 64 years of age with high-risk conditions, H1N1 and seasonal vaccination coverage were 26.3% and 47.6%, respectively. Characteristics independently associated with an increased likelihood of H1N1 vaccination were as follows: higher age; Hispanic race/ethnicity; medical insurance; ability to see a doctor if needed; having a primary doctor; a routine checkup in the previous year; not being a current smoker; and having high-risk conditions other than asthma, diabetes, and heart disease. Characteristics independently associated with seasonal influenza vaccination were similar compared with factors associated with H1N1 vaccination. Immunization programs should work with provider organizations to review efforts made to reach adults with high-risk conditions during the recent pandemic and assess how and where they can increase vaccination coverage during future pandemics.

H1N1 and Seasonal Influenza Vaccination of U.S. Healthcare Personnel, 2010

BackgroundSeasonal influenza vaccination routinely has been recommended for healthcare personnel (HCP) since 1984. The influenza A (H1N1) 2009 monovalent vaccine (H1N1 vaccine) became available in the U.S. in October 2009.PurposeTo assess 2009 H1N1 and seasonal influenza vaccination coverage and identify factors independently associated with vaccination among HCP in the U.S.MethodsData from the 2009–2010 Behavioral Risk Factor Surveillance System (BRFSS) influenza supplemental survey were analyzed in 2011. Multivariable logistic regression and predictive marginal models were performed to identify factors independently associated with vaccination among HCP. The Kaplan-Meier survival analysis procedure was used to estimate the cumulative proportion of people vaccinated.ResultsAmong 16,975 HCP surveyed, 2009 H1N1, seasonal, and any-dose vaccination coverage were 34.1% (95% CI=32.7%, 35.5%); 52.4% (95% CI=50.9%, 53.9%); and 58.0% (95% CI=56.5%, 59.5%), respectively, all of which were significantly higher than those for non-HCP (19.1%, 34.9%, and 40.3%, respectively). The H1N1 vaccination coverage among HCP ranged from 18.4% in Mississippi to 56.1% in Massachusetts and seasonal influenza vaccination coverage ranged from 40.4% in Florida to 73.1% in Nebraska. Characteristics independently associated with an increased likelihood of 2009 H1N1, seasonal, and any-dose vaccinations among HCP were as follows: non-Hispanic white, higher income, having a high-risk condition, having health insurance, the ability to see a doctor if needed, and having had a routine checkup in the previous year.ConclusionsVaccination coverage was higher among HCP than non-HCP but still below the national health objective of 90%. Knowledge of national and state-specific H1N1 and seasonal vaccination coverage among HCP is useful for evaluating the vaccination campaign and implementing strategies for increasing yearly seasonal vaccination coverage and improving vaccination coverage among HCP in possible future pandemics.

Erratum to: Pandemic and seasonal vaccine coverage and effectiveness during the 2009–2010 pandemic influenza in an Italian adult population

Erratum to: Pandemic and seasonal vaccine coverage and effectiveness during the 2009–2010 pandemic influenza in an Italian adult population

Pandemic and seasonal vaccine coverage and effectiveness during the 2009–2010 pandemic influenza in an Italian adult population

To evaluate the response to pandemic vaccination and seasonal and pandemic vaccine effectiveness (VE) in an Italian adult population, during the 2009-2010 influenza season. Data were recorded by interviewing 19,275 subjects (≥35 years), randomly recruited from the general population of the Moli-sani project. Events [influenza-like illness (ILI), hospitalization and death], which had occurred between 1 November 2009 and 31 January 2010 were considered. VE was analyzed by multivariable Poisson regression analysis. Pandemic vaccine coverage was very low (2.4%) in subjects at high-flu risk, aged 35-65 years (N = 8,048); there was no significant preventive effect of vaccine against ILI. Seasonal vaccine coverage was 26.6% in the whole population (63% in elderly and 21.9% in middle-aged subjects at high-flu risk). There was a higher risk to develop ILI in middle-age [VE: -17% (95% CI: -35,-1)] or at high flu-risk [VE: -17% (95% CI: -39, 2)] vaccinated groups. Coverage of pandemic vaccine was very low in a Southern Italy population, with no protective effect against ILI.

Seasonal Influenza Vaccine Coverage Among Pregnant Women: Pregnancy Risk Assessment Monitoring System

Since 2004, the American College of Obstetricians and Gynecologists (ACOG) and the Advisory Committee on Immunization Practices (ACIP) have recommended that pregnant women receive the seasonal influenza vaccine, regardless of pregnancy trimester, because of their increased risk for severe complications from influenza. However, the uptake of the influenza vaccine by pregnant women has been low. During the 2009-2010 influenza season, pregnant women were identified as a priority population to receive the influenza A (H1N1) 2009 (2009 H1N1) monovalent vaccine in addition to the seasonal influenza vaccine. In this issue, we highlight information from the 10 states that collected data using the survey administered by the Pregnancy Risk Assessment and Monitoring System (PRAMS) about seasonal vaccine coverage among women with recent live births and reasons for those who chose not to get vaccinated. The combined estimates from PRAMS of influenza vaccination coverage for the 2009-2010 season, which included data from October 2009 to March 2010, from 10 states were 50.7% for seasonal and 46.6% for 2009 H1N1 vaccine among women with recent live births. Among women who did not get vaccinated, reasons varied from worries about the safety of the vaccines for self and baby to not normally getting the vaccination. Further evaluation is needed on ways to increase influenza vaccination among pregnant women, effectively communicate the risk of influenza illness during pregnancy, and address women's concerns about influenza vaccination safety during pregnancy.

Modelling the effect of seasonal influenza vaccination on the risk of pandemic influenza infection

BackgroundRecent studies have suggested that vaccination with seasonal influenza vaccine resulted in an apparent higher risk of infection with pandemic influenza H1N1 2009. A simple mathematical model incorporating strain competition and a hypothesised temporary strain-transcending immunity is constructed to investigate this observation. The model assumes that seasonal vaccine has no effect on the risk of infection with pandemic influenza.ResultsResults of the model over a range of reproduction numbers and effective vaccination coverage confirm this apparent increased risk in the Northern, but not the Southern, hemisphere. This is due to unvaccinated individuals being more likely to be infected with seasonal influenza (if it is circulating) and developing hypothesised temporary immunity to the pandemic strain. Because vaccinated individuals are less likely to have been infected with seasonal influenza, they are less likely to have developed the hypothesised temporary immunity and are therefore more likely to be infected with pandemic influenza. If the reproduction number for pandemic influenza is increased, as it is for children, an increase in the apparent risk of seasonal vaccination is observed. The maximum apparent risk effect is found when seasonal vaccination coverage is in the range 20-40%.ConclusionsOnly when pandemic influenza is recently preceded by seasonal influenza circulation is there a modelled increased risk of pandemic influenza infection associated with prior receipt of seasonal vaccine.

State-specific changes in cholesterol screening and awareness — United States, 1987–1988

Seasonal influenza vaccination routinely has been recommended for healthcare personnel (HCP) since 1984. The influenza A (H1N1) 2009 monovalent vaccine (H1N1 vaccine) became available in the U.S. in October 2009.To assess 2009 H1N1 and seasonal influenza vaccination coverage and identify factors independently associated with vaccination among HCP in the U.S.Data from the 2009–2010 Behavioral Risk Factor Surveillance System (BRFSS) influenza supplemental survey were analyzed in 2011. Multivariable logistic regression and predictive marginal models were performed to identify factors independently associated with vaccination among HCP. The Kaplan-Meier survival analysis procedure was used to estimate the cumulative proportion of people vaccinated.Among 16,975 HCP surveyed, 2009 H1N1, seasonal, and any-dose vaccination coverage were 34.1% (95% CI=32.7%, 35.5%); 52.4% (95% CI=50.9%, 53.9%); and 58.0% (95% CI=56.5%, 59.5%), respectively, all of which were significantly higher than those for non-HCP (19.1%, 34.9%, and 40.3%, respectively). The H1N1 vaccination coverage among HCP ranged from 18.4% in Mississippi to 56.1% in Massachusetts and seasonal influenza vaccination coverage ranged from 40.4% in Florida to 73.1% in Nebraska. Characteristics independently associated with an increased likelihood of 2009 H1N1, seasonal, and any-dose vaccinations among HCP were as follows: non-Hispanic white, higher income, having a high-risk condition, having health insurance, the ability to see a doctor if needed, and having had a routine checkup in the previous year.Vaccination coverage was higher among HCP than non-HCP but still below the national health objective of 90%. Knowledge of national and state-specific H1N1 and seasonal vaccination coverage among HCP is useful for evaluating the vaccination campaign and implementing strategies for increasing yearly seasonal vaccination coverage and improving vaccination coverage among HCP in possible future pandemics.