MONDAY, March 20, 2006 (HealthDay News) -- A flu shot's ability to work for the elderly appears to depend on certain life events experienced by the patient, a new British study suggests.
The shot appears to be less effective among elderly patients coping with the recent death of a relative or close friend. Conversely, the vaccine seems to be more effective for patients who are married or cohabitating, rather than single. And it's particularly effective among those who say they're happily married.
"We were surprised that in an older sample of individuals, the factors affecting antibody response to the vaccine were not overall stress load and social support, but very specific factors in those categories: bereavement and marital status and satisfaction," said study lead author Anna C. Phillips, a research fellow at the University of Birmingham's School of Sport and Exercise Sciences.
According to the National Institutes of Health, while an annual flu shot may not prevent getting the flu, it greatly reduces an elderly person's risk of serious illness or even death.
NIH statistics show a flu shot reduces the need for hospitalization by 70 percent for elderly not living in nursing homes, and death rates by 85 percent. And for the elderly in nursing homes, a flu shot cuts the risk of hospitalization by 50 percent, the risk of pneumonia by 60 percent, and the risk of death by 75 to 80 percent, according to the NIH.
In 2003, Phillips and her team focused on 184 people -- 80 men and 104 women -- over the age of 65, who were drawn from among five Birmingham-area medical practices. Almost all the patients were non-smoking whites, and nearly all had previously received a flu shot designed to offer protection from three strains of influenza.
To assess antibody responses, blood samples were taken three times over the course of one year -- at the time of the vaccination, one month later, and 12 months later.
The study participants also completed questionnaires at the same intervals regarding demographics -- exposure to major life events (such as marital status, the death of family and friends, housing, and finances); social support perceptions; and health behaviors (such as alcohol/cigarette use, exercise and dietary habits, and sleep patterns).
Reporting in the new issue of the journal Brain, Behavior, and Immunity, the researchers said that, in most instances, there appeared to be no association between the frequency and seriousness of most major life events and the ability of the vaccine to provoke the desired antibody response.
But, there were two big exceptions to this rule -- marital status and bereavement.
Among the one-third of patients who had suffered the loss of a family member or close friend in the previous year, including seven people who had lost a spouse, the antibody response was significantly lower than for patients who had not experienced such a loss.
At one month post-vaccination, the bereaved patients showed a 69 percent lower antibody response, on average, to one flu strain and an 83 percent lower response to a second strain, the researchers found.
On the other hand, for the two-thirds of the men and women who indicated that they were either married or living with someone, the antibody response was significantly higher than among those who were divorced, single, separated or widowed.
In addition, marital satisfaction was also associated with improved antibody response. Unmarried patients were found to have a 74 percent lower antibody response to one strain of flu, compared to those who were happily married.
Phillips said the findings might help health-care providers to get the most vulnerable elderly to improve their chances of getting the greatest benefit from a flu shot.
Phillips acknowledged that it's difficult to change someone's bereavement or marital status. But measures to help people cope more effectively with bereavement (such as counseling), or marital interventions to help increase marital satisfaction and happiness (such as communication training) could improve an individual's emotional and physical well-being, she said.
But Dr. Marc Siegel, a clinical associate professor of medicine at New York University School of Medicine and the author of False Alarm: The Truth About the Epidemic of Fear, suggested that the study's premise may not be definitive.
"I would say that there's a definite interplay between stress and an immune response," said Siegel. "But it's a very different proposition to identify what kind of stress has what effect."
"For example, my research has shown that prolonged chronic worry may diminish an immune response while temporary excitement might augment it," Siegel added. "So it's confusing, because it's not necessarily a linear connection. And I would want to see a lot more research on this."
For more on the flu vaccine, visit the National Institute on Aging.