trivalent influenza vaccine (split virion, inactivated)

**Trivalent influenza vaccine (split virion, inactivated)** is a *split virion inactivated influenza vaccine* containing three strains: two influenza A subtypes (H1N1, H3N2) and one influenza B (Victoria lineage), as recommended annually by WHO for the flu season[1][4]. The split virion is produced by inactivating influenza virus with ultraviolet light and formaldehyde, then disrupting the virus with detergent (usually sodium deoxycholate), which increases safety by reducing reactogenicity[1][2]. The vaccine induces protective immunity through production of antibodies primarily targeting the hemagglutinin surface antigen, and rapidly activates both innate and adaptive immune responses through immune complex formation and Fcγ receptor-dependent activation of monocytes and NK cells, but does not activate Toll-like receptors due to inactivation of viral RNA[2][3]. It is used for active immunization against influenza from 6 months of age and is indicated for the prevention of influenza caused by corresponding circulating strains[1][4]. Commonly administered via intramuscular injection, it does not contain adjuvants[1][2]. Major developers and manufacturers include Sanofi, GSK, Seqirus, Mylan, Abbott, and others.

Brand names

FluvitalFluvaxFluzone TrivalentFluviralAgrifluBegrivacInfluvacothers

Other names

trivalent influenza vaccineTIVsplit virus influenza vaccineinactivated split virion influenza vaccinesplit virion trivalent influenza vaccine