Seasonal Influenza Vaccination

What is influenza ?

• Seasonal Influenza is an acute viral infection that spreads easily from person to person, and can affect anybody from any age group. The severity of infection ranges from mild to acute illness.
• Seasonal influenza viruses cause annual epidemics that peaks during winter in temperate regions.  Worldwide, these annual epidemics are estimated as causing about 3 to 5 million cases of severe illness, and about 250.000 to 500.000 deaths, especially amongst high-risk groups.
• There are 3 types of seasonal influenza viruses (A, B and C). Type A influenza viruses are further classified into subtypes according to the combinations of various virus surface proteins. Currently, the most common subtypes are: influenza A(H1N1) and A(H3N2) which were identified by the World Health Organization (WHO) as the most prevalent strains among humans.
• Type C influenza cases occur much less frequently than A and B. That is why only influenza A and B viruses are included in seasonal influenza vaccines.