The US Food and Drug Administration (FDA) today approved Flublok (Protein Sciences), a trivalent seasonal influenza vaccine made with what the agency calls a "novel technology" that promises to surmount a number of pesky immunization challenges.
The manufacturing process for Flublok, indicated for adults ages 18 through 49, dispenses with eggs as well as influenza viruses, dispelling any fears of catching the flu from the vaccine. It instead relies on recombinant DNA technology and an insect virus expression system, making Flublok the first of its kind, according to the FDA. The process can quickly produce large quantities of an influenza virus protein called hemagglutinin (HA), the active ingredient in all inactivated influenza vaccines that makes it possible for the virus to enter cells. Most antibodies that prevent influenza infection target HA.
Flublok contains 3 recombinant HA proteins to protect against 2 influenza A virus strains — A(H3N2) and 2009 pandemic A(H1N1) — and one influenza B virus strain. The trivalent vaccine now in use for the 2012-2013 influenza season guards against the same 3 strains.
The FDA noted that Flublok's manufacturing process has already been harnessed to make vaccines against other infectious diseases besides influenza.
"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," said Karen Midthun, MF, director of the FDA's Center for Biologics Evaluation and Research in a press release today.
The new vaccine holds other advantages over traditional counterparts, according to a press release issued by Protein Sciences. It is made without the mercury-containing preservative called thimerosal, a source of unfounded fears of mercury poisoning. Flublok also lacks any antibiotics and thus does not contribute to the growth of antibiotic-resistant pathogens.
In a study that compared Flublok to a placebo, the new vaccine proved 44.6% effective against all circulating influenza strains, not just those that matched what the vaccine was designed to cover.
The most commonly reported adverse events for Flublok are those that occur with traditional egg-based vaccines made with inactivated viruses. They include injection-site pain, headache, fatigue, and muscle aches.
Protein Sciences said that it will make a limited supply of Flublok available during the current influenza season. The vaccine will be widely available in the season to follow.
More information about Flublok is available on the FDA Web site.
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Cite this: FDA Okays Novel Flu Vaccine Made Without Eggs, Viruses - Medscape - Jan 16, 2013.