WHO Recommendations for 2010-2011 Influenza Vaccine Viruses

As mentioned in last week's blog entry, twice a year, WHO influenza experts meet to make recommendations on the composition of the next season's influenza vaccines, and this meeting for the upcoming influenza season was held last week. These recommendations provide a guide to national public health authorities and vaccine manufacturers on the viruses to be included in influenza vaccines for the next northern hemisphere season.

WHO recommends that for the 2010-2011 influenza season, the following viruses be included in influenza vaccines:

• An A/California/7/2009 (H1N1)-like virus
• An A/Perth/16/2009 (H3N2)-like virus
• A B/Brisbane/60/2008-like virus

Usually, influenza vaccines for seasonal vaccines contain three different viruses (i.e., are trivalent) -- including A (H1N1), A (H3N2) and B viruses that are considered representative of those that are in circulation. In 2009, because of the H1N1 influenza pandemic, many vaccine manufacturers worldwide have also produced monovalent pandemic vaccines which contain only A/California/7/2009 (H1N1). The decisions on whether to make trivalent and monovalent vaccines containing these viruses will be made by national and regional authorities.

Trivalent vaccines that contain all three of the WHO recommended viruses are expected to protect against both pandemic and seasonal influenza.

Source: WHO http://www.who.int/csr/disease/influenza/201002_RecommendationFAQ.pdf