Repeated Influenza Vaccination Helps Prevent Severe Flu in Older Adults

A study published in the Canadian Medical Association Journal found repeated vaccination for influenza in older adults lowered both the severity of the virus and hospitalization rates, reports EurekAlert . The researchers analyzed flu vaccinations in the current and three previous seasons in people aged 65 years and older who visited 20 Spanish hospitals in 2013-2014 and 2014-2015. They determined repeated vaccination was twice as effective in preventing severe flu in people hospitalized for the virus versus nonsevere cases, and that this effect was consistent irrespective of flu season, virus subtypes, or subject age. "Repeated vaccination for influenza was highly effective in preventing severe and fatal infection caused by influenza in older adults," note the researchers. The investigators also say because severe flu cases may be prevented by two mechanisms, the vaccination's effectiveness against the virus may be greater than that for mild cases, and the advantage of vaccination may be greater than that calculated in earlier studies. "The prevention of severe and fatal infection caused by influenza was observed mainly in persons who were vaccinated in both the current and previous seasons, which reinforces the recommendation of annual vaccination for influenza in older adults," the team concludes.