Researchers found that between 2000 and 2009, the better matched the vaccine was for the influenza strain going around, the fewer residents in US nursing home died or were hospitalized.
Contrary to claims that the youth benefit more from flu vaccines, a 10-year study has found that annual influenza vaccinations can also reduce the hospitalization rate and delay mortality among the elderly.
"This study evidences protection for an elderly population for whom vaccine efficacy has been questioned," said study co-author Stefan Gravenstein, adjunct professor of medicine and health services, policy and practice at Brown University in Rhode Island, US.
"Annual vaccination is the only way to maximize the benefit of vaccine, no matter what the age," Gravenstein noted.
For the study, the researchers analyzed records of millions of nursing home residents.
Year-to-year the ability of the vaccine to fight the flu can vary widely. Sometimes vaccine makers produce a great match that is highly protective. In other years the prevailing flu strain does not match the vaccine well.
The researchers took advantage of this natural variation over the decade 2000-09 to see whether nursing home residents were better off when the match was good compared to when the match was bad.
If vaccines do not help the elderly, as some critics suggest, then nursing home residents should not fare any better when the vaccine is a good match than when it is a bad match.
The results showed that vaccinations help keep some nursing home residents alive and out of the hospital.
The study was published in the Journal of the American Geriatrics Society