The US Food and Drug Administration has approved Protein Sciences Corp's Flublok, the first trivalent influenza vaccine made using an insect virus expression system and recombinant DNA technology.

Unlike current vaccines, Flublok does not use the flu virus or eggs as Protein Sciences' manufacturing technology allows for production of large quantities of the protein hemagglutinin. The latter is the active ingredient in all inactivated influenza vaccines that is essential for entry of the virus into cells in the body.

Karen Midthun, director of the FDA’s Center for Biologics Evaluation and Research, said that 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". Flublok contains three recombinant proteins to help protect against two influenza virus A strains, H1N1 and H3N2, and one influenza virus B strain.

The effectiveness of the vaccine, which has been approved for people aged 18-49, was evaluated in a study that compared the use of Flublok in 2,300 people to a placebo that was given to a control group of similar size. The new treatment was about 44.6% effective against all circulating influenza strains, not just those that matched the strains included in the vaccine.

Manon Cox, Protein Sciences chief executive, said that Flublok is "truly a modern vaccine", adding that “we use advanced scientific technology to make just the active ingredient…without any other viral components. This is the first influenza vaccine on the market to do so".