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Journal Article Research Support, Non-U.S. Gov't Epublish 16 citations

PubMed: 33261680 DOI: 10.1017/S0950268820002952

Influenza vaccine failure in the tropics: a retrospective cohort study of waning effectiveness.

Epidemiol Infect 148:e299

Authors: B E Young, T M Mak, L W Ang, S Sadarangani, H J Ho, A Wilder-Smith, T Barkham, M Chen

Affiliations

  • National Centre for Infectious Diseases, Singapore.
  • Lee Kong Chian School of Medicine, Nanyang Technological University, Singapore.
  • National Public Health Laboratory, National Centre for Infectious Diseases, Singapore.
  • National Public Health and Epidemiology Unit, National Centre for Infectious Diseases, Singapore.
  • Department of Clinical Epidemiology, Office of Clinical Epidemiology, Analytics, and Knowledge, Singapore.
  • London School of Hygiene and Tropical Medicine, London, UK.
  • Heidelberg Institute of Global Health, University of Heidelberg, Germany.
  • Department of Laboratory Medicine, Tan Tock Seng Hospital, Singapore.
  • Department of Microbiology and Immunology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
  • National Centre for Infectious Diseases, Singapore. Saw Swee Hock School of Public Health, National University of Singapore, Singapore.

Abstract

Influenza vaccine effectiveness (VE) wanes over the course of a temperate climate winter season but little data are available from tropical countries with year-round influenza virus activity. In Singapore, a retrospective cohort study of adults vaccinated from 2013 to 2017 was conducted. Influenza vaccine failure was defined as hospital admission with polymerase chain reaction-confirmed influenza infection 2-49 weeks after vaccination. Relative VE was calculated by splitting the follow-up period into 8-week episodes (Lexis expansion) and the odds of influenza infection in the first 8-week period after vaccination (weeks 2-9) compared with subsequent 8-week periods using multivariable logistic regression adjusting for patient factors and influenza virus activity. Records of 19 298 influenza vaccinations were analysed with 617 (3.2%) influenza infections. Relative VE was stable for the first 26 weeks post-vaccination, but then declined for all three influenza types/subtypes to 69% at weeks 42-49 (95% confidence interval (CI) 52-92%, P = 0.011). VE declined fastest in older adults, in individuals with chronic pulmonary disease and in those who had been previously vaccinated within the last 2 years. Vaccine failure was significantly associated with a change in recommended vaccine strains between vaccination and observation period (adjusted odds ratio 1.26, 95% CI 1.06-1.50, P = 0.010).

MeSH

Epidemiology, Vaccines, Cohort Studies, Vaccination, Influenza, Human, Viruses, Influenza Vaccines, Communicable Diseases, Orthomyxoviridae, Infections

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