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FDA advisory committee recommends including pandemic H1N1 strain in next season’s influenza vaccine

The FDA’s Vaccines and Related Biological Products Advisory Committee has unanimously recommended replacing the current influenza vaccine’s A/Brisbane/59/2007 (H1N1)-like virus with the pandemic A/California/7/2009 (H1N1)-like virus strain for the 2010-2011 season.

Committee members agreed that it is still somewhat early in the year to predict what may happen with the pandemic strain in the months ahead, but they agreed that pandemic H1N1’s predominance, unpredictability and the relative absence of seasonal H1N1 warranted the need for the pandemic strain’s inclusion in the vaccine.

The committee also voted unanimously to include an A/Perth/16/2009 (H3N2)-like virus — a strain that is also currently used in the Southern Hemisphere’s vaccine — as opposed to the A/Brisbane/10/2007 (H3N2)-like virus included in this season’s vaccine.

Infectious Diseases in Children Editorial Board member and committee member Theodore Eickhoff, MD, said that H3N2 strain prevalence fluctuates by season, and although he was uncertain what the prevalence of the Perth strain may be in the coming season, he was reluctant to recommend eliminating an H3N2 strain from the 2010-2011 vaccine.

The panel also unanimously recommended keeping the B/Brisbane/60/2008-like virus in the vaccine.

The committee’s decisions on all three strains were in accordance with recommendations made by WHO last week.

Additional panel discussion addressed issues such as growing strains for production in vaccines. Both researchers and a representative for vaccine manufacturers spoke about the difficulty in acquiring enough of certain strains to use in vaccines due to a lack of egg isolates — a possible problem when deciding which strains to include in the vaccine. They also discussed the difficulties in narrowing the list of strains to be used so as to produce vaccines in a timely matter, usually prior to recommendations on which strains should be included. — by Melissa Foster