influenza vaccine (split, inactivated, quadrivalent)

A quadrivalent, inactivated, split-virion influenza vaccine (IIV4) is an **egg-based vaccine** that includes viral antigens from four WHO-recommended influenza strains: two influenza A subtypes (H1N1 and H3N2) and two influenza B lineages (Victoria and Yamagata)[1][2][3][4]. The vaccine works by exposing the immune system to inactivated (killed) virus particles, mainly the surface glycoproteins hemagglutinin (HA) and neuraminidase (NA), as well as some internal proteins (matrix and nucleoprotein), triggering an **antibody-mediated immune response** that protects against the included influenza strains. These vaccines are produced using virus cultured in embryonated chicken eggs, then inactivated and split to reduce reactogenicity. Multiple quadrivalent, split, inactivated influenza vaccines are annually updated and manufactured by various pharmaceutical companies for worldwide use, based on WHO recommendations for the current influenza season. IIV4 is approved for prevention of influenza in persons 6 months of age and older and is given via intramuscular injection.

Brand names

Fluzone QuadrivalentAfluria QuadrivalentInfluvac TetraFluQuadriAfluria Quad

Other names

IIV4IIV-4IIV 4inactivated influenza vaccinequadrivalent influenza vaccine (split virion, inactivated)