trivalent split virion influenza vaccine

A **trivalent split virion influenza vaccine** is an inactivated influenza vaccine formulation that protects against three strains of influenza: two influenza A viruses (H1N1 and H3N2) and one influenza B virus (typically of the B/Victoria lineage)[1][2][4][5][6]. The "split virion" designation indicates that the influenza virus particles are chemically disrupted (split) to remove the viral envelope, making the vaccine less reactogenic while maintaining immunogenicity[3][7]. These vaccines work by exposing the immune system to hemagglutinin and neuraminidase antigens from the selected circulating strains, thus inducing neutralizing antibodies and protective immunity. The 2024–2025 trivalent split virion vaccines do not include the B/Yamagata lineage, following its apparent disappearance from circulation[1][2][6]. Vaccines are typically administered annually by intramuscular injection, with some intranasal options for specific age groups[4][5].

Brand names

Afluria TrivalentFluarix TrivalentFlucelvax TrivalentFlulaval TrivalentFluMist TrivalentFluzone TrivalentFluBlok TrivalentFluad Adjuvant Trivalent

Other names

trivalent influenza vaccinetrivalent inactivated influenza vaccineIIV3IIV-3IIV 3split virus influenza vaccinesplit virion influenza vaccinetrivalent split flu vaccine