Efluelda

Efluelda is a high-dose quadrivalent inactivated influenza vaccine designed for the prevention of influenza (flu) in adults aged 60 or 65 years and older, depending on the country. It contains split and inactivated influenza viruses from four strains recommended by WHO and European health authorities each season—two influenza A subtypes (H1N1 and H3N2) and two B lineages (Victoria and Yamagata). The vaccine is produced using viruses propagated in embryonated chicken eggs, which are then harvested, inactivated with formaldehyde, purified via sucrose density gradient centrifugation, chemically disrupted to create a "split virus," further purified, concentrated to achieve a higher hemagglutinin antigen content per strain than standard-dose vaccines (60 μg HA per strain), and suspended for injection[1][3][4][7]. The mechanism of action involves stimulating the immune system to produce antibodies against the included viral antigens. This confers protection by enabling rapid immune response upon exposure to circulating flu viruses matching those strains[1]. Efluelda is administered as a single intramuscular injection (0.7 mL), typically into the deltoid muscle[3]. Clinical studies have shown that it induces at least as strong an immune response as other high-dose or standard-dose flu vaccines in older adults[2][4].

Brand names

EflueldaEfluelda Tetra

Other names

Quadrivalent Influenza Vaccine (Split Virion, Inactivated) High-DoseQIV-HD