adjuvanted quadrivalent inactivated influenza vaccine (CSL Seqirus)

MF59-adjuvanted quadrivalent inactivated influenza vaccine (aIIV4), marketed as FLUAD Quad, is a seasonal influenza vaccine developed by Seqirus (a CSL company). It is specifically designed for older adults (originally aged 65+ and recently extended to 50+ in some regions) to overcome immunosenescence. The vaccine contains four influenza virus antigens—two A strains (H1N1 and H3N2) and two B strains (Victoria and Yamagata lineages)—and is formulated with the MF59 adjuvant. MF59 is a squalene-based oil-in-water emulsion that enhances the immune response by creating a local immunostimulatory environment at the injection site, recruiting and activating antigen-presenting cells, and improving the transport of antigens to the lymph nodes. This results in higher antibody titers and broader cross-reactivity compared to non-adjuvanted standard-dose vaccines, providing enhanced protection against seasonal influenza in the elderly population.

Brand names

FLUAD QuadFLUAD Quadrivalent

Other names

MF59-adjuvanted quadrivalent inactivated influenza vaccineMF-59-adjuvanted quadrivalent inactivated influenza vaccineMF 59-adjuvanted quadrivalent inactivated influenza vaccineMF59-adjuvanted QIVMF-59-adjuvanted QIVMF 59-adjuvanted QIV