Impact of repeated vaccination on vaccine effectiveness against influenza A(H3N2) and B during 8 seasons.
Clin Infect Dis. 2014 Nov 15; 59(10):1375-85.CI

Abstract

BACKGROUND

Recent studies suggest that influenza vaccination in the previous season may influence the effectiveness of current-season vaccination, but this has not been assessed in a single population over multiple years.

METHODS

Patients presenting with acute respiratory illness were prospectively enrolled during the 2004-2005 through 2012-2013 influenza seasons. Respiratory swabs were tested for influenza and vaccination dates obtained from a validated registry. Vaccination status was determined for the current, previous, and prior 5 seasons. Vaccine effectiveness (VE) was calculated for participants aged ≥9 years using logistic regression models with an interaction term for vaccination history.

RESULTS

There were 7315 enrollments during 8 seasons; 1056 (14%) and 650 (9%) were positive for influenza A(H3N2) and B, respectively. Vaccination during current only, previous only, or both seasons yielded similar protection against H3N2 (adjusted VE range, 31%-36%) and B (52%-66%). In the analysis using 5 years of historical vaccination data, current season VE against H3N2 was significantly higher among vaccinated individuals with no prior vaccination history (65%; 95% confidence interval [CI], 36%-80%) compared with vaccinated individuals with a frequent vaccination history (24%; 95% CI, 3%-41%; P = .01). VE against B was 75% (95% CI, 50%-87%) and 48% (95% CI, 29%-62%), respectively (P = .05). Similar findings were observed when analysis was restricted to adults 18-49 years.

CONCLUSIONS

Current- and previous-season vaccination generated similar levels of protection, and vaccine-induced protection was greatest for individuals not vaccinated during the prior 5 years. Additional studies are needed to understand the long-term effects of annual vaccination.

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Authors+Show Affiliations

McLean HQ
Center for Clinical Epidemiology and Population Health, Marshfield Clinic Research Foundation, Wisconsin.
Thompson MG
Influenza Division, Centers for Disease Control and Prevention, Atlanta, Georgia.
Sundaram ME
Center for Clinical Epidemiology and Population Health, Marshfield Clinic Research Foundation, Wisconsin.
Meece JK
Integrated Research and Development Laboratory, Marshfield Clinic Research Foundation.
McClure DL
Center for Clinical Epidemiology and Population Health, Marshfield Clinic Research Foundation, Wisconsin.
Friedrich TC
Department of Pathobiological Sciences, University of Wisconsin School of Veterinary Medicine, Wisconsin National Primate Research Center, Madison.
Belongia EA
Center for Clinical Epidemiology and Population Health, Marshfield Clinic Research Foundation, Wisconsin.

MeSH

AdolescentAdultAgedAged, 80 and overChildComorbidityFemaleHumansImmunization, SecondaryInfluenza A Virus, H3N2 SubtypeInfluenza B virusInfluenza VaccinesInfluenza, HumanMaleMiddle AgedOutcome Assessment, Health CareRisk FactorsSeasonsVaccinationYoung Adult

Pub Type(s)

Journal Article
Research Support, U.S. Gov't, P.H.S.

Language

eng

PubMed ID

25270645