Flu Vaccine May Be Less Effective If Administered Every Year, Studies Suggest.

reports that a “growing body of evidence” indicates that repeated flu shots every year may “gradually reduce the effectiveness of the vaccines under some circumstances.” A study released by Wisconsin’s Marshfield Clinic Research Foundation reported “recently that children who had been vaccinated annually over a number of years were more likely to contract the flu than those who were vaccinated only in the season in which they were studied.” In a recent interview with STAT, lead researcher and epidemiologist Dr. Edward Belongia recounted, “The vaccine was significantly more effective...if they had not been vaccinated in the previous five years.” http://www.statnews.com/2015/11/11/flu-shots-reduce-effectiveness/