Influenza vaccine

The main purpose of seasonal influenza vaccination is to avoid severe disease from infection with influenza virus. Influenza vaccine is available in two preparations, Trivalent Inactivated Influenza Vaccine (TIV) and Live, Attenuated Influenza Vaccine (LAIV). TIV and LAIV are antigenically equivalent and contain three annually-recom­mended influenza strains--influenza A (H3N2), influenza A (H1N1), and influenza B. Each year, the influenza viruses in the vaccine are assessed on the basis of global surveillance for influenza viruses and may be changed. Most countries in the Americas Region are licensed for use of the TIV.