Lineage-matched versus mismatched influenza B vaccine effectiveness following seasons of marginal influenza B circulation

SUMMARYInfluenza vaccine effectiveness (VE) has to be estimated anew for every season to explore vaccines’ protective effect in the population. We report VE estimates against laboratory-confirmed influenza A(H1N1)pdm09, A(H3N2) and influenza B among children aged 2–17 years, using test-negative design. Pooled data from two German federal states’ surveillance systems for acute respiratory illness from week 40/2012 to 20/2016 was used, yielding a total of 10 627 specimens. Odds ratios and 95% confidence intervals (95% CIs) for the association between laboratory-confirmed influenza and vaccination status were calculated by multivariate logistic regression adjusting for age, sex, illness onset and federal state. VE was estimated as 1-Odds Ratio. Overall adjusted VE was 33% (95% CI: 24·3–40·7). A strong variation of VE between the seasons and subtypes was observed: highest season- and subtype-specific VE of 86·2% (95% CI: 41·3–96·7) was found against A(H1N1)pdm09 in 7–17-year-olds in 2015/16. Low estimates of VE were observed against A(H3N2) in any season, e.g. 1·5% (95% CI: −39·3–30·3) in 2014/15. Estimates showed a tendency to higher VE among 7–17-year-old children, but differences were not statistically significant. Although our findings are common in studies estimating influenza VE, we discussed several explanations for observed low VE.

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Influenza Vaccine Effectiveness Among Children for the 2017–2018 Season

Journal of the Pediatric Infectious Diseases Society ◽

10.1093/jpids/piz077 ◽

2019 ◽

Vol 9 (4) ◽

pp. 468-473 ◽

Cited By ~ 2

Author(s):

Lauren N Powell ◽

Rodolfo E Bégué

Keyword(s):

Influenza Vaccine ◽

Influenza A ◽

Influenza Season ◽

Vaccine Effectiveness ◽

Influenza B ◽

Immunization Registry ◽

Previous Season ◽

Waning Immunity ◽

Small Benefit ◽

Susceptible Populations

Abstract Background The 2017–2018 influenza season was of high severity. Circulating influenza strains change periodically, making it important to determine vaccine effectiveness on an annual basis, especially for susceptible populations. The primary aim of our study was to estimate the effectiveness of the influenza vaccine among children. Secondary aims were to assess the effect of previous season vaccination and intraseasonal waning of immunity. Methods Children 6 months to 17 years of age tested for influenza during the 2017–2018 season were included. Clinical charts were reviewed, and immunization status was confirmed via the Louisiana Immunization Registry. Influenza vaccine effectiveness (IVE) was estimated in a test-negative design by comparing vaccination status of influenza-positive vs influenza-negative cases. Results A total of 3595 children were included, 26% of whom tested positive for influenza, mostly type A (79%); 15% had received an influenza vaccine prior to illness: 8% among the influenza-positive and 17% among influenza-negative cases (P <.0001). IVE for the 2017–2018 influenza season was 52% overall (95% confidence interval, 38%–62%), 49% for influenza A, and 60% for influenza B. While receiving current year (2017–2018) vaccine had the most effect, receiving the previous year (2016–2017) vaccine had a small benefit and no interference. We found no evidence of waning immunity of the vaccine for the 2017–2018 season. Conclusions IVE was moderate for children. Previous year vaccination had a small but significant benefit and there was no evidence of waning immunity in our cohort. Ongoing national and local surveillance is important to understand the benefit of influenza vaccination.

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Influenza vaccine effectiveness in preventing inpatient and outpatient cases in a season dominated by vaccine-matched influenza B virus

Human Vaccines & Immunotherapeutics ◽

10.1080/21645515.2015.1038002 ◽

2015 ◽

Vol 11 (7) ◽

pp. 1626-1633 ◽

Cited By ~ 10

Author(s):

Iván Martínez-Baz ◽

Ana Navascués ◽

Francisco Pozo ◽

Judith Chamorro ◽

Esther Albeniz ◽

...

Keyword(s):

Influenza Vaccine ◽

Vaccine Effectiveness ◽

Influenza B Virus ◽

Influenza B ◽

B Virus

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Influenza vaccine effectiveness against laboratory-confirmed influenza in hospitalised adults aged 60 years or older, Valencia Region, Spain, 2017/18 influenza season

Eurosurveillance ◽

10.2807/1560-7917.es.2019.24.31.1800461 ◽

2019 ◽

Vol 24 (31) ◽

Author(s):

Ainara Mira-Iglesias ◽

F Xavier López-Labrador ◽

Víctor Baselga-Moreno ◽

Miguel Tortajada-Girbés ◽

Juan Mollar-Maseres ◽

...

Keyword(s):

Influenza Vaccine ◽

Influenza A ◽

Vaccine Effectiveness ◽

Influenza Viruses ◽

Influenza B ◽

Current Season ◽

Hospitalised Patients ◽

Influenza A H1n1 ◽

Vaccine Type ◽

The Impact

Introduction Influenza immunisation is recommended for elderly people each season. The influenza vaccine effectiveness (IVE) varies annually due to influenza viruses evolving and the vaccine composition. Aim To estimate, in inpatients ≥ 60 years old, the 2017/18 trivalent IVE, overall, by vaccine type and by strain. The impact of vaccination in any of the two previous seasons (2016/17 and 2015/16) on current (2017/18) IVE was also explored. Methods This was a multicentre prospective observational study within the Valencia Hospital Surveillance Network for the Study of Influenza and Respiratory Viruses Disease (VAHNSI, Spain). The test-negative design was applied taking laboratory-confirmed influenza as outcome and vaccination status as main exposure. Information about potential confounders was obtained from clinical registries and/or by interviewing patients; vaccine information was only ascertained by registries. Results Overall, 2017/18 IVE was 9.9% (95% CI: −15.5 to 29.6%), and specifically, 48.3% (95% CI: 13.5% to 69.1%), −29.9% (95% CI: −79.1% to 5.8%) and 25.7% (95% CI: −8.8% to 49.3%) against A(H1N1)pdm09, A(H3N2) and B/Yamagata lineage, respectively. For the adjuvanted and non-adjuvanted vaccines, overall IVE was 10.0% (95% CI: −24.4% to 34.9%) and 7.8% (95% CI: −23.1% to 31.0%) respectively. Prior vaccination significantly protected against influenza B/Yamagata lineage (IVE: 50.2%; 95% CI: 2.3% to 74.6%) in patients not vaccinated in the current season. For those repeatedly vaccinated against influenza A(H1N1)pdm09, IVE was 46.4% (95% CI: 6.8% to 69.2%). Conclusion Our data revealed low vaccine effectiveness against influenza in hospitalised patients ≥60 years old in 2017/18. Prior vaccination protected against influenza A(H1N1)pdm09 and B/Yamagata-lineage.

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Interim estimates of 2019/20 vaccine effectiveness during early-season co-circulation of influenza A and B viruses, Canada, February 2020

Eurosurveillance ◽

10.2807/1560-7917.es.2020.25.7.2000103 ◽

2020 ◽

Vol 25 (7) ◽

Cited By ~ 6

Author(s):

Danuta M Skowronski ◽

Macy Zou ◽

Suzana Sabaiduc ◽

Michelle Murti ◽

Romy Olsha ◽

...

Keyword(s):

Confidence Interval ◽

Influenza Vaccine ◽

Influenza A ◽

Vaccine Effectiveness ◽

Influenza B ◽

Surveillance Network ◽

Early Season ◽

Influenza Illness

Interim results from Canada's Sentinel Practitioner Surveillance Network show that during a season characterised by early co-circulation of influenza A and B viruses, the 2019/20 influenza vaccine has provided substantial protection against medically-attended influenza illness. Adjusted VE overall was 58% (95% confidence interval (CI): 47 to 66): 44% (95% CI: 26 to 58) for A(H1N1)pdm09, 62% (95% CI: 37 to 77) for A(H3N2) and 69% (95% CI: 57 to 77) for influenza B viruses, predominantly B/Victoria lineage.

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Pooled influenza vaccine effectiveness estimates for Australia, 2012–2014

Epidemiology and Infection ◽

10.1017/s0950268816000819 ◽

2016 ◽

Vol 144 (11) ◽

pp. 2317-2328 ◽

Cited By ~ 15

Author(s):

S. G. SULLIVAN ◽

K. S. CARVILLE ◽

M. CHILVER ◽

J. E. FIELDING ◽

K. A. GRANT ◽

...

Keyword(s):

General Practice ◽

Logistic Regression ◽

Confidence Interval ◽

Influenza Vaccine ◽

Sample Size ◽

Vaccine Coverage ◽

Vaccine Effectiveness ◽

Influenza Surveillance ◽

Influenza B ◽

Age Group

SUMMARYData were pooled from three Australian sentinel general practice influenza surveillance networks to estimate Australia-wide influenza vaccine coverage and effectiveness against community presentations for laboratory-confirmed influenza for the 2012, 2013 and 2014 seasons. Patients presenting with influenza-like illness at participating GP practices were swabbed and tested for influenza. The vaccination odds of patients testing positive were compared with patients testing negative to estimate influenza vaccine effectiveness (VE) by logistic regression, adjusting for age group, week of presentation and network. Pooling of data across Australia increased the sample size for estimation from a minimum of 684 to 3,683 in 2012, from 314 to 2,042 in 2013 and from 497 to 3,074 in 2014. Overall VE was 38% [95% confidence interval (CI) 24–49] in 2012, 60% (95% CI 45–70) in 2013 and 44% (95% CI 31–55) in 2014. For A(H1N1)pdm09 VE was 54% (95% CI–28 to 83) in 2012, 59% (95% CI 33–74) in 2013 and 55% (95% CI 39–67) in 2014. For A(H3N2), VE was 30% (95% CI 14–44) in 2012, 67% (95% CI 39–82) in 2013 and 26% (95% CI 1–45) in 2014. For influenza B, VE was stable across years at 56% (95% CI 37–70) in 2012, 57% (95% CI 30–73) in 2013 and 54% (95% CI 21–73) in 2014. Overall VE against influenza was low in 2012 and 2014 when A(H3N2) was the dominant strain and the vaccine was poorly matched. In contrast, overall VE was higher in 2013 when A(H1N1)pdm09 dominated and the vaccine was a better match. Pooling data can increase the sample available and enable more precise subtype- and age group-specific estimates, but limitations remain.

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Age-specific vaccine effectiveness of seasonal 2010/2011 and pandemic influenza A(H1N1) 2009 vaccines in preventing influenza in the United Kingdom

Epidemiology and Infection ◽

10.1017/s0950268812001148 ◽

2012 ◽

Vol 141 (3) ◽

pp. 620-630 ◽

Cited By ~ 30

Author(s):

R. G. PEBODY ◽

N. ANDREWS ◽

D. M. FLEMING ◽

J. McMENAMIN ◽

S. COTTRELL ◽

...

Keyword(s):

Influenza Vaccine ◽

Pandemic Influenza ◽

Influenza A ◽

Vaccine Effectiveness ◽

Influenza B ◽

The United Kingdom ◽

Previous Season ◽

Negative Case ◽

Influenza A H1n1 ◽

Control Study

SUMMARYAn analysis was undertaken to measure age-specific vaccine effectiveness (VE) of 2010/11 trivalent seasonal influenza vaccine (TIV) and monovalent 2009 pandemic influenza vaccine (PIV) administered in 2009/2010. The test-negative case-control study design was employed based on patients consulting primary care. Overall TIV effectiveness, adjusted for age and month, against confirmed influenza A(H1N1)pdm 2009 infection was 56% (95% CI 42–66); age-specific adjusted VE was 87% (95% CI 45–97) in <5-year-olds and 84% (95% CI 27–97) in 5- to 14-year-olds. Adjusted VE for PIV was only 28% (95% CI −6 to 51) overall and 72% (95% CI 15–91) in <5-year-olds. For confirmed influenza B infection, TIV effectiveness was 57% (95% CI 42–68) and in 5- to 14-year-olds 75% (95% CI 32–91). TIV provided moderate protection against the main circulating strains in 2010/2011, with higher protection in children. PIV administered during the previous season provided residual protection after 1 year, particularly in the <5 years age group.

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Hospital-based vaccine effectiveness against influenza B lineages, Hong Kong, 2009−14

Vaccine ◽

10.1016/j.vaccine.2016.03.032 ◽

2016 ◽

Vol 34 (19) ◽

pp. 2164-2169 ◽

Cited By ~ 13

Author(s):

Susan S. Chiu ◽

Shuo Feng ◽

Kwok-Hung Chan ◽

Janice Y.C. Lo ◽

Eunice L.Y. Chan ◽

...

Keyword(s):

Hong Kong ◽

Vaccine Effectiveness ◽

Influenza B

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Vaccine effectiveness against influenza-associated hospitalization among children aged < 13 years using a hospital-based surveillance system in Minnesota, 2013 – 2016

Open Forum Infectious Diseases ◽

10.1093/ofid/ofx162.142 ◽

2017 ◽

Vol 4 (suppl_1) ◽

pp. S60-S60

Author(s):

Ashley Fowlkes ◽

Hannah Friedlander ◽

Andrea Steffens ◽

Kathryn Como-Sabetti ◽

Dave Boxrud ◽

...

Keyword(s):

Influenza Vaccine ◽

Influenza Vaccination ◽

Influenza A ◽

Respiratory Illness ◽

Vaccine Effectiveness ◽

Influenza Viruses ◽

Point Estimate ◽

Influenza B ◽

Current Season ◽

Immunization Registry

Abstract Background Due to marked variability in circulating influenza viruses each year, annual evaluation of the vaccine’s effectiveness against severe outcomes is essential. We used the Minnesota Department of Health’s (MDH) Severe Acute Respiratory Illness (SARI) surveillance to evaluate vaccine effectiveness (VE) against influenza-associated hospitalization over three influenza seasons. Methods Residual respiratory specimens from patients admitted with SARI were sent to the MDH laboratory for influenza RT-PCR testing. Medical records were reviewed to collect patient data. Vaccination history was verified using the state immunization registry. We included patients aged ≥6 months to < 13 years, after which immunization reporting is not required, hospitalized from the earliest influenza detection after July through April each year. We defined vaccinated patients as those ≥1 dose of influenza vaccine in the current season. Children aged < 9 years with no history of vaccination were considered vaccinated if 2 were doses given a month apart. Partially vaccinated children were excluded. We estimated VE as 1 minus the adjusted odds ratio (x100%) of influenza vaccination among influenza cases vs. negative controls, controlling for age, race, days from onset to admission, comorbidities, and admission month. Results Among 2198 SARI patients, 763 (35%) were vaccinated for influenza, 180 (8.2%) were partially vaccinated, and 1255 (57%) were unvaccinated. Influenza was detected among 202 (9.2%) children, and significantly more frequently among children aged ≥5 years (17%) compared with younger children (7.4%). The adjusted VE in 2013–14 was 68% (95% Confidence Interval: 34, 85), but was non-significant during the 2014–15 and 2015–16 seasons (Figure). Estimates of VE by influenza A subtypes varied substantially by year; VE against influenza B viruses was significant, but could not be stratified by year. VE was impacted when live attenuated influenza vaccine recipients were excluded. Conclusion We report moderately high influenza VE in 2013–14 and a point estimate higher than other published estimates from outpatient data in 2014–15. These results, underscore the importance of influenza vaccination to prevent severe outcomes such as hospitalization. Disclosures All authors: No reported disclosures.

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Variations in Seasonal Influenza Vaccine Effectiveness due to Study Characteristics: A Systematic Review and Meta-analysis of Test-Negative Design Studies

Open Forum Infectious Diseases ◽

10.1093/ofid/ofaa177 ◽

2020 ◽

Vol 7 (7) ◽

Author(s):

George N Okoli ◽

Florentin Racovitan ◽

Christiaan H Righolt ◽

Salaheddin M Mahmud

Keyword(s):

Full Text ◽

Seasonal Influenza ◽

Statistical Significance ◽

Vaccine Effectiveness ◽

Bibliographic Databases ◽

Influenza B ◽

Medical Conditions ◽

Respiratory Specimen ◽

Study Characteristics ◽

H3n2 Influenza

Abstract Background Study characteristics influence vaccine effectiveness (VE) estimation. We examined the influence of some of these on seasonal influenza VE estimates from test-negative design (TND) studies. Methods We systematically searched bibliographic databases and websites for full-text publications of TND studies on VE against laboratory-confirmed seasonal influenza in outpatients after the 2009 pandemic influenza. We followed the Cochrane Handbook for Systematic Reviews of Interventions guidelines. We examined influence of source of vaccination information, respiratory specimen swab time, and covariate adjustment on VE. We calculated pooled adjusted VE against H1N1 and H3N2 influenza subtypes, influenza B, and all influenza using an inverse-variance random-effects model. Results We included 70 full-text articles. Pooled VE against H1N1 and H3N2 influenza subtypes, influenza B, and all influenza was higher for studies that used self-reported vaccination than for those that used medical records. Pooled VE was higher with respiratory specimen collection within ≤7 days vs ≤4 days of symptom onset, but the opposite was observed for H1N1. Pooled VE was higher for studies that adjusted for age but not for medical conditions compared with those that adjusted for both. There was, however, a lack of statistical significance in almost all differences in pooled VE between compared groups. Conclusions The available evidence is not strong enough to conclude that influenza VE from TND studies varies by source of vaccination information, respiratory specimen swab time, or adjustment for age/medical conditions. The evidence is, however, indicative that these factors ought to be considered while designing or evaluating TND studies of influenza VE.

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