(AP) - Flu shots may do more for the elderly than fend off the flu bug - they also protect against heart disease and stroke, new research shows.
Results of a large study of more than 286,000 elderly, appearing in Thursday's New England Journal of Medicine, show hospital stays for heart disease or stroke during two flu seasons were substantially reduced among those who got flu shots.
"Influenza may be even worse than we thought. And flu shots might be even better than we thought," said researcher Dr. Kristin Nichol of the Minneapolis Veterans Affairs Medical Center.
New government figures show influenza contributes to an average 36,000 annual U.S. deaths.
Flu shots are now recommended for all adults 50 and older. In 2001, about 63 percent of those over 65 were vaccinated in the United States.
The flu vaccine reduces deaths overall and prevents pneumonia in the elderly, and some small studies have suggested that they help ward off heart disease and strokes.
The researchers checked medical records for those over 65 enrolled in three managed-care plans in the Minneapolis, Portland, Ore., and New York City areas during two flu seasons - 1998-1999 and 1999-2000. Of the 140,055 people studied in the first flu season, 56 percent were vaccinated. In the second, 60 percent of the 146,328 enrollees got flu shots.
They compared hospital stays for those who got shots and those who didn't. Flu vaccination cut hospitalizations for heart disease by 19 percent both seasons, the findings showed. Hospital stays for stroke were reduced by 16 percent the first season and 23 percent the second.
"There are very few things we can do in medicine that provide these kinds of benefits over a very short period of time. This is huge," said Nichol.
Dr. William Schaffner, head of preventive medicine at Vanderbilt University School of Medicine, said the results need to be investigated further but reinforce an important message.
"It offers even more reassurance and affirmation as to the importance of getting your flu shot annually," said Schaffner.
The researchers also found immunization cut hospital stays by about one-third for the flu and pneumonia, a common complication, and reduced by half the risk of death from any cause. The findings are similar to previous studies.
Nichol said the connection between the flu and heart disease and stroke isn't clear but the virus could be affecting blood vessels and the development of clots in the brain and heart.
Schaffner said there should be a national program to provide flu shots, noting that the government has launched a smallpox vaccine program without a single case.
"We have an estimated 20-30,000 deaths due to influenza. We need an organized, national vaccine program each year," he said.
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On the Net:
New England Journal: http://www.nejm.org
CDC flu information: http://www.cdc.gov/ncidod/diseases/flu/fluvirus.htm
