A panel of experts advising the U.S. Food and Drug Administration has recommended changing one of the three strains of flu included in this season's influenza vaccine for next season's version, the Dow Jones news service reported Wednesday.
Each annual vaccine typically has two strains of influenza A and one strain of influenza B that are most likely to strike during the upcoming season. But the decision about which strains to include is made months in advance.
The FDA panel said next season's vaccine should include the same strains of influenza A as this season's shot, but that a newer "B" strain be included in the upcoming vaccine, Dow Jones said.
In a typical season, one or two of the three strains included in the annual vaccine are changed from the prior season, although all three changed in the 2008-2009 flu shot from the year-earlier vaccine, the news service said.
The strains used in the vaccine are grown in chicken eggs. The process of creating the next season's vaccine typically starts in January or February. It takes about eight months to create the 130 million doses needed, Dow Jones said.