Potentially deadly influenza outbreaks in nursing homes are less likely to occur when large numbers of staff and residents get flu shots, according to a study issued today by the RAND Corporation.

The study by the nonprofit research organization found that nursing homes were 60 percent less likely to have a cluster of influenza-like illness cases if more than 55 percent of the staff and more than 89 percent of the residents were vaccinated for influenza.

Researchers defined clusters of influenza-like illness as more than three cases with influenza-like symptoms reported within 72 hours in close proximity within the nursing home.

"Simply immunizing nursing home residents against influenza is not going to ensure they're protected from getting the flu," said Lisa R. Shugarman, a RAND researcher and lead author of the study. "It's only the combination of high rates of immunization for residents and staff that appears to make the difference."

The RAND Health study titled "The Influence of Staff and Resident Immunization Rates on Influenza-like Illness Outbreaks in Nursing Homes" appears in the Nov. 15 issue of the Journal of the American Medical Directors Association.

Influenza outbreaks in nursing homes are common and can result in prolonged hospitalizations and death for vulnerable elderly residents, particularly those with serious chronic health problems.

From 1979 to 2000, influenza hospitalization rates for elderly patients were 17 times higher than the average rate, and more than 90 percent of the patients who died were elderly. According to another study, nursing home residents age 65 and older were three times more likely to be hospitalized for influenza than people of similar ages who did not live in nursing homes.

The influenza vaccine can be 86 percent effective for healthy adults when the vaccine matches the prevailing influenza strain. However, studies have shown that the vaccine is less ef
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Contact: Lisa Sodders
oec@rand.org
310-451-6913
RAND Corporation
15-Nov-2006