February 23, 2010 — In a unanimous vote, an advisory panel to the US Food and Drug Administration (FDA) recommended yesterday that the 2010 to 2011 seasonal influenza vaccine should include a strain of the pandemic A (H1N1) virus in addition to 2 other strains.
At this time, the vaccine for the pandemic virus is being administered in monovalent form in addition to the traditional trivalent vaccine for seasonal influenza.
A strain of the pandemic A (H1N1) virus would replace a nonpandemic A (H1N1) strain in the trivalent vaccine under the recommendation from the Vaccines and Related Biological Products Advisory Committee (VRBPAC) of the FDA's Center for Biologics Evaluation and Research.
Including the pandemic virus in a trivalent cocktail eliminates the need to administer 2 separate vaccines. In addition, vaccine manufacturers will not have to churn out 2 separate vaccines, as they did in 2009, resulting in production delays.
The VRBPAC recommendation assumes that the pandemic virus will continue to be the dominant one in circulation. That is also the assumption of the World Health Organization (WHO), which recommended last week that seasonal influenza vaccine for the northern hemisphere in the 2010 to 2011 season include a strain of the pandemic H1N1 virus, along with 2 nonpandemic viruses. WHO put forward the same vaccine recipe last September for the southern hemisphere's 2010 influenza season. In both cases, WHO left the decision of whether the pandemic virus should appear in a trivalent or monovalent formulation to individual countries.
The 3 strains recommended by WHO for both northern and southern hemisphere vaccines are an A/California/7/2009 (H1N1)–like virus, which is a pandemic strain; an A/Perth/16/2009 (H3N2)–like virus; and a B/Brisbane/60/2008-like virus. VRBPAC recommended the same set of strains. The B/Brisbane/60/2008-like virus appears in the current seasonal influenza vaccine for the United States; the other 2 strains are newcomers.
