GlaxoSmithKline is recalling remaining doses of a popular four-in-one flu vaccine because of effectiveness problems.
The company alerted U.S. customers Tuesday that the vaccine can lose potency over time and fail to adequately protect against some strains of the flu. The Flulaval Quadrivalent Thimerosal-free vaccine in prefilled syringes is designed to protect against four strains of influenza virus.
But Glaxo said in a letter it “cannot rule out potential suboptimal protection” in people who received the vaccine in early January or later. The letter was sent to about 1,000 customers throughout the U.S., including wholesale distributors, pharmacies, government agencies and physicians.