influenza vaccine live, trivalent

Live attenuated influenza vaccine, trivalent (LAIV-T) is an intranasal vaccine designed to prevent influenza caused by three specific virus strains: two influenza A subtypes (typically H1N1 and H3N2) and one influenza B lineage. Unlike inactivated vaccines, LAIV-T contains cold-adapted, temperature-sensitive, attenuated viruses that replicate in the cooler environment of the nasopharynx but not in the lower respiratory tract. This mechanism induces a multifaceted immune response, including mucosal IgA, systemic antibodies, and cellular immunity, closely mimicking natural infection. Originally developed by MedImmune (acquired by AstraZeneca), the trivalent formulation was the first intranasal influenza vaccine licensed in the United States (2003). While highly effective in children, it has largely been superseded by quadrivalent formulations (LAIV4) in many national immunization programs to provide broader protection against both influenza B lineages.

Brand names

FluMist

Other names

LAIV-TLAIV3LAIV-3LAIV 3trivalent live attenuated influenza vaccinelive attenuated influenza vaccine, trivalent