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FDA Approves New Flu Vaccine
The FDA has approved Flublok (Protein Sciences Corp.), the first trivalent influenza vaccine made using an insect virus (baculovirus) expression system and recombinant DNA technology. The vaccine is approved for the prevention of seasonal influenza in people 18 through 49 years of age.
Unlike current flu vaccines, Flublok does not use the influenza virus or chicken eggs in its production. The new vaccine’s manufacturing technology allows the production of large quantities of the influenza virus protein hemagglutinin (HA) — the active ingredient in all inactivated influenza vaccines that is essential for entry of the virus into cells. Most of the antibodies that prevent influenza virus infection are directed against HA. While the technology is new to flu vaccine production, it is used to make vaccines that have been approved by the FDA to prevent other infectious diseases.
Flublok contains three recombinant HA proteins to help protect against two influenza virus A strains (H1N1 and H3N2) and one influenza virus B strain.
The effectiveness of Flublok was evaluated in a U.S. study that compared the vaccine with placebo in approximately 2,300 people. Flublok was 45% effective against all circulating influenza strains, not just the strains that matched those included in the vaccine.
A safety evaluation was conducted in a study of approximately 2,500 people who were vaccinated with Flublok. The most commonly reported adverse events included injection-site pain, headache, fatigue, and muscle aches — events that are also typical for conventional egg-based, inactivated influenza vaccines.
Flublok has a shelf life of 16 weeks from the date of manufacture.
Source: FDA; January 16, 2013.