Influenza vaccination in developing countries

Abstract

Influenza virus (types A, B and C) infection is one of the most common infectious diseases globally and is responsible for millions of sick-days every year, especially in younger children and those with underlying chronic systemic diseases. The infection occurs both as sporadic disease and as epidemics/ pandemics. From public health point of view type-A influenza virus is most significant as it affects other species also (in addition to humans), undergoes frequent antigenic changes thus escaping immune system and leading to epidemics/ pandemics. Vaccination is considered one of the best preventive strategies against this virus. In general, two types of influenza vaccines are available: trivalent inactivated influenza vaccine (TIV) and live-attenuated influenza vaccine (LAIV). However, there are a number of challenges in implementing vaccination programs for influenza, especially for developing countries with limited resources and many other competing health priorities. The current influenza A 2009H1N1 pandemic has shown the world how fragile today's resources in pandemic and pre-pandemic, but also seasonal, vaccines are. This article discusses, in brief, the development, immunogenicity, efficacy and safety of influenza vaccines (seasonal, pre-pandemic and pandemic 2009H1N1 vaccines) along with the rationale, current status and future prospects of influenza vaccination in infants, children and adolescents.