Flu vaccine revamped for next season
Haven already battled flu this year with a mismatched vaccine, public health officials have taken the unprecedented step of changing all three influenza strains in the vaccine under development for the 2008-2009 season.
"Now, this sounds like a major change, because this really hasn't occurred before," Nancy Cox, MD, director of the Influenza Division at the Centers for Disease Control and Prevention (CDC), said at a press conference. However, Cox noted that the change was in keeping with a twice-annual vaccine recommendation by national and international public health experts.
The current vaccine has been undermined by the emerging Brisbane strain of influenza A (H3N2), an antigenic variant of one of the strains in the vaccine (A/Wisconsin). In addition most of influenza B viruses currently circulating are of a lineage that is different from the vaccine strain. "The match is not optimal, both for the H3N2 component of the vaccine and the influenza B component," said Cox, adding that last year the CDC and vaccine collaborators were concerned about the Brisbane strain and discussed changing the vaccine component recommendations. "Unfortunately, we did not have a viable egg isolate that could be used by the manufacturers, so it was necessary to continue to use the Wisconsin virus in the vaccine," she said.
As a result, a fairly mild flu season sharply increased in severity, with H3N2 beginning to cause the majority of infections. By the week ending Feb. 23, 2008, 49 states (all but Florida) were reporting widespread influenza activity.
Haven already battled flu this year with a mismatched vaccine, public health officials have taken the unprecedented step of changing all three influenza strains in the vaccine under development for the 2008-2009 season.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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