Recombinant Trivalent Influenza Vaccine (Flublok®): A Review of Its Use in the Prevention of Seasonal Influenza in Adults

Flublok (R) is a trivalent influenza vaccine manufactured using the baculovirus-insect cell system, which has a number of differences compared with the traditional embryonated chicken egg system. Flublok (R) is the first vaccine containing recombinant protein to be approved for the prevention of seasonal influenza, and is indicated in the USA in adults aged 18-49 years. In a large, placebo-controlled, phase III trial in individuals aged 18-49 years, Flublok (R) met the US FDA requirements for immunogenicity, effectiveness and safety, despite a high incidence of antigenic mismatch between confirmed cases of influenza and the vaccine component strains. Flublok (R) was also compared with Fluzone (R) in two noninferiority trials in older adults aged 50-64 or >= 65 years; although noninferiority was shown for a number of endpoints in these trials, Flublok (R) is not currently approved in these age groups. Flublok (R) is a useful and generally well-tolerated vaccination option for the prevention of seasonal influenza in adults aged 18-49 years, including those with egg allergy.