Safe and effective vaccines are available for influenza and have been used for more than 60 years. Among healthy adults, influenza vaccine can provide reasonable protection. However among the elderly, influenza vaccine may be less effective in preventing illness but may reduce severity of disease and incidence of complications and deaths.
Vaccination is especially important for people at higher risk of serious influenza complications, and for people who live with or care for high risk individuals.
WHO recommends annual vaccination for:
1.pregnant women at any stage of pregnancy
2.children aged 6 months to 5 years
3.elderly individuals (≥65 years of age)
4.individuals with chronic medical conditions
5.health-care workers.
Influenza vaccination is most effective when circulating viruses are well-matched with vaccine viruses. Influenza viruses are constantly changing, and the WHO Global Influenza Surveillance and Response System (GISRS) – a partnership of National Influenza Centres around the world –monitors the influenza viruses circulating in humans.
For many years WHO has updated its recommendation on vaccine composition biannually that targets the 3 (trivalent) most representative virus types in circulation (two subtypes of influenza A viruses and one B virus). Starting with the 2013-2014 northern hemisphere influenza season, quadrivalent vaccine composition has been recommended with a second influenza B virus in addition to the viruses in the conventional trivalent vaccines. Quadrivalent influenza vaccines are expected to provide wider protection against influenza B virus infections.
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