inactivated influenza vaccine, quadrivalent

Inactivated influenza vaccine, quadrivalent (IIV4) is a seasonal vaccine indicated for active immunization to prevent influenza disease caused by influenza A subtype viruses and type B viruses. As a quadrivalent formulation, it contains antigens from four distinct influenza strains: two influenza A subtypes (typically H1N1 and H3N2) and two influenza B lineages (Victoria and Yamagata). The vaccine is produced by inactivating (killing) the virus, often using formaldehyde or heat, and may be presented as a split-virion or subunit vaccine. It works by inducing the production of neutralizing antibodies against the viral hemagglutinin (HA) protein, which prevents the virus from attaching to and entering host cells. Formulations are updated annually based on World Health Organization (WHO) recommendations to match circulating seasonal strains. IIV4 is primarily administered via intramuscular injection and is licensed for use in various age groups depending on the specific manufacturer's product.

Brand names

Fluzone QuadrivalentFluarix QuadrivalentFluLaval QuadrivalentAfluria QuadrivalentFlucelvax Quadrivalent

Other names

Quadrivalent inactivated influenza vaccineQIVsplit-virion influenza vaccine, quadrivalentsubunit influenza vaccine, quadrivalent