Both hemispheric influenza vaccine recommendations would have missed near half of the circulating viruses in Madagascar

Julia Guillebaud; Jean-Michel Héraud; Norosoa H Razanajatovo; Alicia A Livinski; Wladimir J Alonso

doi:10.1111/irv.12517

Both hemispheric influenza vaccine recommendations would have missed near half of the circulating viruses in Madagascar

Influenza Other Respir Viruses. 2017 Nov;11(6):473-478. doi: 10.1111/irv.12517.

Authors

Julia Guillebaud¹, Jean-Michel Héraud¹, Norosoa H Razanajatovo¹, Alicia A Livinski², Wladimir J Alonso³

Affiliations

¹ National Influenza Centre, Virology Unit, Institut Pasteur de Madagascar, Antananarivo, Madagascar.
² National Institutes of Health Library, Office of Research Services, Office of Management, National Institutes of Health, Bethesda, MD, USA.
³ Laboratory for Human Evolutionary and Ecological Studies, Institute of Biosciences, University of São Paulo, São Paulo, Brazil.

Abstract

Background: Influenza immunization still poses a critical challenge globally and specifically for tropical regions due to their complex influenza circulation pattern. Tropical regions should select the WHO's Northern Hemisphere or Southern Hemisphere recommended vaccine composition based on local surveillance. Analyses of influenza immunization effectiveness have neglected to account for the proportion of circulating viruses prevented from causing infection each year. We investigate this question for Madagascar, where influenza vaccines are not widely available.

Methods: Seventy-eight Malagasy influenza strains characterized from 2002 to 2014 were challenged with hypothetical scenarios in which the WHO's Northern Hemisphere and Southern Hemisphere recommended vaccine compositions were provided to the population. Match between circulating and vaccine strains was determined by haemagglutination inhibition assays. Strain-specific positive matches were scored assuming 9 months of protection, and scenarios incorporated vaccine delays from zero to 5 months.

Results: Malagasy influenza strains matched 54% and 44%, respectively, with the Northern Hemisphere and Southern Hemisphere recommended vaccine strains when the vaccine was delivered as soon as available. The matching values further decreased when additional delivery and application delays were considered. Differences between recommended compositions were not statistically significant.

Conclusion: Our results showed matching with the Northern Hemisphere vaccine barely above 50%, even in the more favourable scenario. This suggests that if implemented, routine influenza vaccines would not provide an optimal protection against half of the influenza strains circulating in any epidemic season of Madagascar. We suggest that this limitation in influenza vaccine efficacy deserves greater attention, and should be considered in cost/benefit analyses of national influenza immunization programmes.

Keywords: Madagascar; influenza; match; seasonality; timing; vaccination.

Publication types

Research Support, U.S. Gov't, P.H.S.
Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

Health Planning Guidelines*
Hemagglutination Inhibition Tests
Humans
Immunization Programs / economics
Immunization Programs / methods
Influenza A virus / isolation & purification*
Influenza A virus / physiology
Influenza Vaccines / administration & dosage*
Influenza Vaccines / adverse effects
Influenza, Human / epidemiology*
Influenza, Human / virology
Madagascar / epidemiology
Seasons
Vaccination*
World Health Organization

Substances

Influenza Vaccines