Study Conducted by Marshfield Clinic Research Foundation Shows Influenza Vaccines Provide Substantial Protection
Friday, April 8th, 2016 -- 8:17 AM
-A systematic review of nearly a decade of influenza studies across the globe shows influenza vaccines provided substantial protection against the H1N1 strain that has circulated since the 2009 pandemic, and against type B viruses.The study also found that vaccination generates lower protection against the H3N2 viruses that have been infecting humans since the 1960s. The findings are based on a report published in The Lancet Infectious Diseases. The analysis, which included studies published from 2007 through early 2015, was conducted by Dr. Edward Belongia and colleagues at Marshfield Clinic Research Foundation and the University of Minnesota.
The research team screened 3,368 studies and selected 56 that met strict criteria for assessing vaccine effectiveness against different flu subtypes. Seasonal flu vaccines are updated each year and contain two subtypes of influenza A virus and one or two strains of influenza B. The study team found that seasonal vaccines provided 61 percent protection against the H1N1 strain and 54 percent protection against type B. Vaccine protection was only 33 percent for the H3N2 strain. Although vaccine effectiveness can decline in older adults due to aging of the immune system, the review found that protection against H1N1 and type B was maintained even in the oldest age groups.
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