Flu Vaccine Doesn't Protect Seniors From Pneumonia (HealthDay)

THURSDAY, July 31 (HealthDay News) -- Flu vaccine may not protect olderpeople from pneumonia once they get the disease, researchers report.

Older, frail adults are more susceptible to getting the flu, even ifthey have been vaccinated, and once getting the flu, they are moresusceptible to such complications as pneumonia. It had been thought thatflu vaccine would prevent flu -- and pneumonia -- across all groups ofseniors, but this benefit appears to be largely confined to younger,healthier seniors.

"In seniors, flu vaccine was not linked to a reduced risk ofpneumonia," said lead researcher Michael L. Jackson, a postdoctoral fellowat the Group Health Center for Health Studies in Seattle.

Jackson still recommends that seniors get flu vaccine, however. "Therehave been good randomized trials that show, at least in healthy seniors,that the vaccine reduces the risk of influenza," he said. "However,earlier studies have overestimated how well the vaccine works in reducingcomplications of influenza. So, the vaccine may not reduce the risk ofcomplications as much as previously thought," he said.

Among young healthy seniors, the vaccine reduces the risk of flu,Jackson said. "When you look at the total population of seniors, whichincludes people over 75 and people that have chronic health diseases -- lung disease, heart disease, diabetes, and things like that -- we don'tknow if the vaccine is effective in the seniors," he said. "People withthese chronic diseases are more susceptible to getting the flu, and theyare more likely to develop pneumonia if they do get influenza."

The report is published in the Aug. 2 issue of The Lancet.

For the study, Jackson's team collected data on 1,173 people betweenthe ages of 65 and 94 who developed pneumonia They compared theseindividuals with 2,346 people who did not get pneumonia. Both groups hadsimilar rates of flu vaccination over the three seasons of studies, theresearchers say.

The researchers found that vaccinated seniors who got the flu were aslikely to develop pneumonia as unvaccinated seniors who got the flu.

Dr. Pascal James Imperato, dean of the master of public health programat the State University of New York Downstate Medical Center in New YorkCity, was not surprised by these results.

"We know that elderly people do not form sufficient antibodies tocertain vaccines, the flu vaccine included," Imperato said. "In addition,people in their 70s and 80s and 90s are more prone to pneumonia with orwithout influence. A number of these pneumonias may be secondary to othercauses aside from influenza."

Even though many of the elderly will not develop sufficient antibodiesto the flu vaccine, getting the shot is still worthwhile, Imperato said."Having many people vaccinated builds up a herd immunity to disease, andyou create barriers to transmission," he added.

Dr. Marc Siegel, a clinical associate professor of medicine at New YorkUniversity School of Medicine in New York City, said the results of thisstudy fly in the face of prevailing wisdom.

Siegel noted that 36,000 people in the United States die each year fromthe flu. "Over 90 percent of them are elderly," he said. "We give the flushot primarily to prevent elderly deaths.

The effectiveness of the flu vaccine varies year to year, however,depending on how good a match it is for the circulating strains ofinfluence. "In the best years, the flu vaccine is really only 40 to 60percent effective," Siegel added.

In addition, Siegel thinks that the flu vaccine protects against othercomplication including respiratory diseases, which can also be fatal."There are plenty of flu-related complications that are life-threateningbesides pneumonia," he said.

"This study is a reminder that flu vaccines are not a panacea, but theyare valuable, because they cut down on the incidence of influenza," Siegelsaid. "Flu shots definitely cut down on the number of flu-relateddeaths."

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