FDA delays GlaxoSmithKline's H5N1 bird flu vaccine

The FDA recently delayed the approval of GlaxoSmithKline's H5N1 bird flu vaccine designed to be used in the event of a pandemic, saying it needed more time to assess the vaccine.

The agency said it needed more time to assess the product, citing an "administrative matter that has recently been rectified," according to Reuters.

Mounting evidence shows a relation between Pandemrix, GlaxoSmithKline's earlier H1N1 flu vaccine, and narcolepsy cases in European children who received the vaccine, raising concerns as to whether the regulator should approve the similar H5N1 vaccine. Both of the vaccines contain a booster that ramps up the body's immune response to vaccination.

In November, a 14-member advisory panel to the FDA voted to recommend GSK's H5N1 vaccine to ward off bird flu. The panel examined several European studies that indicated an increase in the number of narcolepsy cases but ultimately found that the vaccine's potential benefits outweighed the risks. New data, however, suggests that the link between Pandemrix and narcolepsy could be stronger than originally reported, Reuters reports.

The FDA had been scheduled to wrap up its review of the vaccine this past December, and it is unknown as to how much longer the agency's review will last, according to PMLiVE.

The World Health Organization has maintained a pandemic alert for the H5N1 bird flu strain because of its high mortality rate of about 60 percent. While the virus is not transmissible between humans and birds, health officials remain concerned that the virus could mutate and spread.