US health regulators have approved a new four-strain seasonal influenza vaccine made by GlaxoSmithKline, the company said.
The US Food and Drug Administration has approved Fluarix Quadrivalent to immunise children aged three and older and adults against flu virus subtypes A and B contained in the vaccine.
It is the first intramuscular vaccine to protect against four influenza strains. Three-strain flu vaccines currently administered help protect against the two most common A virus strains and the B strain expected to be predominant in a given year, the company said.
Since 2000, however, two B virus strains have circulated to varying degrees each season, meaning patients infected with the B virus not contained in the vaccine were not immunised.