Recombinant trivalent influenza vaccine (flublok(®)): a review of its use in the prevention of seasonal influenza in adults.

Flublok(®) 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(®) 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(®) 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(®) was also compared with Fluzone(®) 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(®) is not currently approved in these age groups. Flublok(®) 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.