Study: New Mutation In Flu Virus Made Last Season’s Flu Vaccines Less Effective

The Philadelphia (PA) Inquirer (6/26, Faherty) reports that last season’s influenza vaccines “were only 19 percent effective in preventing medical visits due to flu-related complications, according to the U.S. Centers for Disease Control and Prevention.” Up “until now, researchers did not know why.”

        HealthDay (6/26, Preidt) reports that the vaccine’s reduced effectiveness was “due to a new mutation in the flu virus,” according to a study published in Cell Reports. A “mutation in the H3N2 virus led to a mismatch between it and the H3N2 strain used to create the vaccine, the researchers explained,” meaning that the shot “did not fully prime the immune system to recognize and attack the version of the virus that circulated during the last flu season.”