robert. wrote:How does the pharmaceutical industry know what strain of flu to vaccinate against?
Dr. Who tells them.
Flu viruses are constantly changing, so the vaccine composition is reviewed each year and updated as needed based on which influenza viruses are making people sick, the extent to which those viruses are spreading, and how well the previous season’s vaccine protects against those viruses.
More than 100 national influenza centers in over 100 countries conduct year-round surveillance for influenza. This involves receiving and testing thousands of influenza virus samples from patients. The laboratories send representative viruses to five World Health Organization (WHO) Collaborating Centers for Reference and Research on Influenza, which are located in the following places:
Atlanta, Georgia, USA (Centers for Disease Control and Prevention, CDC);
London, United Kingdom (The Francis Crick Institute);
Melbourne, Australia (Victoria Infectious Diseases Reference Laboratory);
Tokyo, Japan (National Institute for Infectious Diseases); and
Beijing, China (National Institute for Viral Disease Control and Prevention).
Twice a year, the World Health Organization (WHO) organizes a consultation with the Directors of the WHO Collaborating Centers, essential regulatory laboratories and representatives of key national laboratories and academies. They review the results of surveillance, laboratory, and clinical studies, and the availability of vaccine viruses and make recommendations on the composition of the influenza vaccine. These meetings take place in February for selection of the upcoming Northern Hemisphere’s seasonal influenza vaccine and in September for the Southern Hemisphere’s vaccine. WHO recommends specific vaccine viruses for inclusion in influenza vaccines, but then each country makes their own decision about which viruses should be included in influenza vaccines licensed in their country.
In the United States, the Food and Drug Administration (FDA) makes the final decision about vaccine viruses for influenza vaccines to be sold in the U.S. Information about circulation of influenza viruses and available vaccine viruses is summarized and presented to an advisory committee of the FDA in February each year for the U.S. decision about which viruses to include in the upcoming season’s vaccine.