The U.S. Food and Drug Administration has approved Flublok, the first trivalent influenza vaccine made using an insect virus expression system and recombinant DNA technology, for prevention of seasonal influenza in people ages 18 to 49.
“This approval represents a technological advance in the manufacturing of an influenza vaccine,” Karen Midthun, MD, director of the FDAs Center for Biologics Evaluation and Research, said in a news release. “The new technology offers the potential for faster start-up of the vaccine manufacturing process in the event of a pandemic, because it is not dependent on an egg supply or on availability of the influenza virus.”
Unlike current flu vaccines, Flublok does not use the influenza virus or eggs in its production. Flubloks novel manufacturing technology allows for production of large quantities of the influenza virus protein, hemagglutinin, the active ingredient in all inactivated influenza vaccines that is essential for entry of the virus into cells in the body. The majority of antibodies that prevent influenza virus infection are directed against hemagglutinin.
Each year, the FDA, World Health Organization, Centers for Disease Control and Prevention and other public health experts collaborate on the review of influenza disease surveillance and laboratory data collected from around the world to identify strains that may cause the most illness in the upcoming season. Based on that information and on the recommendations of its Vaccines and Related Biological Products Advisory Committee, the FDA selects the different influenza strains each year that manufacturers should include in their vaccines for the U.S. population for the upcoming influenza season. The closer the match between the circulating strains causing disease and the strains in the vaccine, the better the protection against influenza.
Flublok contains three, full-length, recombinant hemagglutinin proteins to help protect against two influenza virus A strains, H1N1 and H3N2, and one influenza virus B strain.
As it does with all influenza vaccines, the FDA will evaluate Flublok annually prior to use by the public each flu season. The recombinant hemagglutinin proteins produced in the baculovirus expression system and included in Flublok will be assessed by the FDA.
Flubloks safety evaluation was conducted in a study of about 2,500 people who were vaccinated with Flublok. The most commonly reported adverse events included pain at the site of injection, headache, fatigue and muscle aches events also typical for conventional egg-based, inactivated influenza vaccines.
Flublok has a shelf life of 16 weeks from the date of manufacture, according to the FDA. Healthcare providers should check the expiration date before administering Flublok, which is manufactured by Protein Sciences Corp. of Meriden, Conn.