Michael Osterholm, director of the Center for Infectious Disease Research and Policy at the University of Minnesota and professor of the Environmental Health Sciences at the School of Public Health, published an analysis last year in The Lancet that showed evidence flu shots were less effective than commonly reported, USA Today said.
Osterholm found the intranasal flu vaccine -- sold as FluMist -- protected 83 percent of children age 8 and under. There was, however, mixed evidence about how well FluMist protected seniors and a lack of evidence on its effect on those ages 8-59, Osterholm said.
Given their good safety record and noting that "moderate" protection was better than no protection at all, Osterholm said everyone older than 6 months should get a flu vaccine annually.
A preliminary study by the Centers for Disease Control and Prevention in Atlanta on the effectiveness of this year's vaccine found it was effective 62 percent of the time.
Drug companies have felt little pressure to make truly "game-changing" vaccines, because experts and the public seem satisfied with the status quo, Osterholm said.
"The No. 1 deterrent to getting new flu vaccines is the perception that the current ones are good enough," Osterholm told USA Today.
A next-generation flu vaccine could take 15 years and cost more than $1 billion, Osterholm estimated.