WEDNESDAY, Oct. 3, 2007 (HealthDay News) -- If you're over 65, getting an annual flu shot will reduce the risk you'll be hospitalized with flu complications by 27 percent and cut your risk of flu-related death by 48 percent.
That's the conclusion of new research published in the Oct. 4 issue of the New England Journal of Medicine.
"This is a bad disease but a good vaccine," said the study's lead author, Dr. Kristin Nichol, chief of medicine at the VA Medical Center in Minneapolis. "Many people fail to appreciate the serious complications of influenza."
Not everyone is convinced, however, that the flu vaccine is quite so effective in the elderly. A study released last week in the October issue of The Lancet Infectious Diseases questioned death-rate reductions seen in many previous studies. The researchers behind last week's study pointed out that many studies fail to include those over 70 -- and thus, most at risk of flu complications -- and that the people who receive flu vaccines may actually be healthier than those who don't.
But, Nichol's study was designed to answer some of those concerns. And even after compensating for numerous factors, the researchers still found that the flu vaccine reduces hospitalizations and death rates in the elderly.
"I think this study is reassuring, and it does the best job you can do to assess the efficacy of flu vaccine in the elderly," said Dr. John Treanor, author of an accompanying editorial in the New England Journal of Medicine, and a professor of medicine at the University of Rochester Medical Center, in New York.
"The vaccine is nowhere near 100 percent effective, and it's probably true that the elderly don't respond as well as younger people do. But, that does not mean that we shouldn't use the vaccine in older people, but that we should think about other ways to prevent the disease," said Treanor, adding that he'd like to see many more health-care workers receive the vaccination, as well as more healthy children.
Each year, as many as 20 percent of the U.S. population is infected with the flu, according to the federal Centers for Disease Control and Prevention. As many as 200,000 people are hospitalized annually due to flu complications, and 36,000 people die each year because of the flu. Those most at risk of serious flu complications include the elderly and young children, the CDC says.
The new study began in 1990 and included data through the 1999-2000 flu season for people from 18 different groups of community-dwelling elderly members of one health maintenance organization. Additionally, information on members of two other HMOs was included from 1996 through 2000.
The study included almost 300,000 unvaccinated people and more than 415,000 vaccinated individuals. All were over 65 years old.
In the entire study group, there were 4,599 hospitalizations and almost 9,000 deaths from influenza during the 10-year study period. On average, hospitalization rates were 0.7 percent for unvaccinated people and 0.6 percent for those vaccinated. On average, death rates were 1.6 percent and 1.0 percent, respectively.
The researchers found that those rates varied from flu season to flu season, with more hospitalizations and deaths occurring in years when the flu vaccine wasn't a good match against the strains of circulating flu.
The researchers also looked to see if hospitalizations and death rates were lower in the summer, which would suggest that the effect wasn't from the vaccine. They didn't find such an association, suggesting that the reduction during influenza season was, in fact, due to the vaccine.
"This is the most definitive look linking outcomes to vaccination status," Treanor said.
Nichol said: "I think this study goes a long way to addressing concerns and shows what the influences of the influenza vaccine might be even after taking into account age, health conditions and previous hospitalizations."
She added that, in addition to preventing hospitalizations and deaths, the flu vaccine is "highly cost-effective and even cost-saving."
To learn more about flu vaccine, visit the U.S. Centers for Disease Control and Prevention.