Seasonal influenza vaccine policy, use and effectiveness in the tropics and subtropics - a systematic literature review.

Siddhivinayak Hirve,Julia Fitzner,Katelijn Vandemaele,John Paget,Philipp Lambach,Wenqing Zhang

doi:10.1111/irv.12374

Abstract

AimThe evidence needed for tropical countries to take informed decisions on influenza vaccination is scarce. This article reviews policy, availability, use and effectiveness of seasonal influenza vaccine in tropical and subtropical countries.MethodGlobal health databases were searched in three thematic areas – policy, availability and protective benefits in the context of human seasonal influenza vaccine in the tropics and subtropics. We excluded studies on monovalent pandemic influenza vaccine, vaccine safety, immunogenicity and uptake, and disease burden.ResultsSeventy‐four countries in the tropics and subtropics representing 60% of the world's population did not have a national vaccination policy against seasonal influenza. Thirty‐eight countries used the Northern Hemisphere and 21 countries the Southern Hemisphere formulation. Forty‐six countries targeted children and 57 targeted the elderly; though, the age cut‐offs varied. Influenza vaccine supply increased twofold in recent years. However, coverage remained lower than five per 1000 population. Vaccine protection against laboratory‐confirmed influenza in the tropics ranged from 0% to 42% in the elderly, 20–77% in children and 50–59% in healthy adults. Vaccinating pregnant women against seasonal influenza prevented laboratory‐confirmed influenza in both mothers (50%) and their infants <6 months (49–63%).ConclusionGuidelines on vaccine composition, priority risk groups and vaccine availability varied widely. The evidence on vaccine protection was scarce. Countries in the tropics and subtropics need to strengthen and expand their evidence‐base required for making informed decisions on influenza vaccine introduction and expansion, and how much benefit to expect.

Highlights

Influenza may affect up to 10% of the world’s population every year 1 with substantial morbidity and mortality.[2,3,4,5] With immunization being one of the most powerful and cost effective interventions against infectious diseases,[6] vaccination remains the main strategy to protect populations against influenza-associated morbidity and mortality
The immediate goal is to increase by 2016 the global vaccine production capacity to produce enough vaccine to equitably immunize 70% of the world population with a pandemic vaccine that gives an adequate protection within 6 months of vaccine seed transfer to manufacturers in the event of a pandemic.[11]
The Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) statement was used to guide the process and reporting of our review (Appendix A).17The outcomes of interest were to review the current status of national policy for seasonal influenza vaccination, national guidelines for priority population groups and vaccine composition, vaccine use and effectiveness

Summary

Introduction

Influenza may affect up to 10% of the world’s population every year 1 with substantial morbidity and mortality.[2,3,4,5] With immunization being one of the most powerful and cost effective interventions against infectious diseases,[6] vaccination remains the main strategy to protect populations against influenza-associated morbidity and mortality. An increasing number of countries in the tropics and subtropics have introduced seasonal influenza vaccination in their national immunization policies and/or expanded their policies to include maternal influenza immunization.[12,13] This is critical given the WHO Strategic Advisory Committee of Experts on Immunization recommendation in 2012 that countries with seasonal influenza vaccine programmes prioritize persons at high risk of severe a 2016 The Authors.

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