BETHESDA, MD. — The influenza vaccine for the 2010-2011 influenza season in the United States should include a pandemic influenza A(H1N1) strain, instead of one of the two seasonal influenza A strains in the current vaccine, a Food and Drug Administration advisory panel has recommended.
At a meeting of the FDA's Vaccines and Related Biological Products Advisory Committee, the panel unanimously voted 12-0 that the current influenza A(H1N1) strain included in the 2009-2010 seasonal flu vaccine, an A/Brisbane/59/2007 (H1N1)–like virus, should be replaced with a pandemic A(H1N1) vaccine virus, an A/California/7/2009–like virus, the component of the monovalent pandemic vaccine used this past season. Also included in the vaccine should be an A/Perth/16/2009 (H3N2)–like virus and a B/Brisbane/60/2008–like virus (B/Victoria lineage), the panel said.
The panel's recommendation is based on the finding that the vast majority of influenza A(H1N1) viruses circulating worldwide have been the pandemic strain. At the meeting, Nancy Cox, Ph.D., director of the influenza division at the Centers for Disease Control and Prevention, told the panel that there has been very little evidence of circulating seasonal A(H1N1) influenza viruses, which “most likely pose a low risk” in the forthcoming season in the northern hemisphere.
The panel meets every year at this time to make preliminary recommendations on the components of the trivalent vaccine for the forthcoming influenza season in the northern hemisphere. It considered information on the strains circulating worldwide as well as recommendations announced by the World Health Organization for the 2010-2011 influenza vaccine to be used in the northern hemisphere.
The panel voted to replace the influenza A(H3N2) strain included in the current vaccine with a southern hemisphere vaccine virus A/Perth/16/2009 (H3N2)–like virus. Dr. Cox said that activity of seasonal A(H3N2) viruses has been “relatively low” worldwide, compared with previous years, and what has been circulating antigenically is closely related to the A/Perth/16/2009 virus.
The panel voted to retain the influenza B component that is used in the current vaccine, a B/Brisbane/60/2008–like virus (B/Victoria lineage). Influenza B viruses have been circulating at low levels in many countries, but Victoria lineage viruses continue to predominate, Dr. Cox said. She pointed out, however, that it is always difficult to predict which lineage of influenza B viruses will predominate.
The panel's recommendations were the same as the WHO recommendations for the three components of the influenza vaccine for the forthcoming season in the northern hemisphere.
Seasonal A(H1N1) influenza viruses 'most likely pose a low risk' in the forthcoming season.
Source: DR. COX