LONDON (AP) _ A new analysis of 40 years of research provides more evidence that flu shots are not as effective in the elderly as commonly believed. But health officials said older people should still be vaccinated.
The research, done by an international collaboration of scientists known as the Cochrane Review Group, found the vaccine is only about 28 percent effective when given to people over 65. Older people are particularly vulnerable to influenza.
The findings are similar to those of a study done by U.S. National Institutes of Health that found flu shots for the elderly in the United States had not saved lives.
However, the World Health Organization and the U.S. Centers for Disease Control and Prevention said the findings, published Thursday on the Web site of the Lancet medical journal, do not change their recommendation that elderly people get the shots.
``There are a number of studies published that report on varying degrees of effectiveness. But there are also a lot of studies that point to the fact that the vaccines are effective in preventing the serious complications that lead to hospitalizations and death, and that's an important note that we should never lose sight of,'' said Tom Skinner, a CDC spokesman.
``If I had a loved one who was in the high risk group, I would strongly recommend they get vaccinated,'' he said.
In the study, researchers combined the results of 64 studies and concluded that flu shots reduced by 28 percent the chance of an elderly person ending up in a hospital with influenza or pneumonia. The results were better when the elderly people lived in nursing homes.
``The effectiveness is thought to be high. It is assumed to be 70, 80 or 90 percent in the elderly,'' said the study's leader, epidemiologist Dr. Tom Jefferson. The study shows ``it's not as effective ... that needs to be clearly presented to our customers, not fudged.''
Dr. Pascal James Imperato, community health director at the State University of New York Downstate Medical Center, said it was not surprising the vaccine appeared to be less effective in elderly people living at home than in those in nursing homes.
People in nursing homes are under regular medical surveillance, and influenza infections can be easily verified by tests.
``This does not hold true for the elderly in the community, where one has to rely largely on a history of coming down with the flu,'' he said. ``This history is often misleading because people acquire a range of viruses which can produce symptoms similar to the flu. However, they will report having the flu.''
Calling the vaccine ineffective may not be fair in many cases because the illness was not influenza but another disease not targeted by the vaccine. And it has long been known that the elderly do not produce antibodies as well as younger people when vaccinated, which may partly explain the lower effectiveness rates, Imperato said.
Whatever the explanation, flu shots do provide some degree of protection to the elderly and do lessen the severity of illness, he said.