When it comes to flu vaccination, there are always doubters, but once again, many will line up for the shot.

Flu shots: Do they help? Some…

Among medical researchers and health professionals, however, confidence in those benefits has turned in the opposite direction. After six decades of steadily expanded use among the elderly, flu vaccination for seniors has come under critical scrutiny in several studies. Collectively, they suggest that for those over 65, flu vaccination may confer fewer benefits than have been widely advertised.

Researchers that the new skepticism is overdue. The medical profession’s wariness should have been piqued by a simple but glaring disconnect: Flu vaccination rates among American seniors have risen more than fourfold over 25 years — to 65% in 2007. During the same period, however, hospitalization for, and death due to, flu and pneumonia appear to have declined only marginally in the nation’s 65-and-over population. It just doesn’t add up.

Studies on the effectiveness of flu vaccine in older populations have had a wide range of methodological problems. But although their weaknesses are varied, their effect is almost invariably skewed in one direction.”

Since the late 1950s, when flu vaccine became widely available to Americans, a belief in the vaccine’s lifesaving benefits for older people has been the cornerstone of the nation’s immunization policy, a perennial conclusion of published medical studies and an article of popular faith. Not surprisingly, then, the studies that cast doubt on those benefits have been met with concern and hostility.

For some seniors, the flu vaccine does not appear to provide the kind of robust protection it does for others.

Flawed fatality count?

The centers for Disease Control and Prevention estimate that flu kills about 36,000 Americans annually. But while that shocking figure seems straightforward enough, calculating the totals of death by flu is anything but. For most of those counted as flu fatalities, pneumonia — a frequent complication of flu — is listed as the cause of death.

For those 65 and older, the lesson is clear: A dose of pneumococcal vaccine is a good way to bolster protection among those at risk of suffering complications of flu. A single dose, says the U.S. Department of Health and Human Services, can protect against 23 types of Streptococcus pneumonia bacteria thought responsible for causing more than 90% of pneumonia cases.

The latest of the critical studies, published in the Aug. 2 issue of the Lancet, followed the cases of 3,519 patients over age 65 — all admitted to the hospital with pneumonia either during or just before the flu seasons of 2000-2002. After separating those who had been vaccinated against flu from those who had not, and accounting for other health factors, the study found that the group that had been immunized against flu appeared no less likely to develop pneumonia requiring hospitalization than those who had not.

On the heels of that study came a second, conducted by Canadian researchers, that looked at the death rates of elderly hospitalized patients with pneumonia. About 8% of the patients vaccinated for flu died, compared with 15% of the nonvaccinated patients.

But when researchers paired patients of similar age and health status and then looked at their comparative likelihood of dying, they found that age and frailty — not flu vaccination — seemed to account for which patients were most likely to die of pneumonia during flu season. At the same time, they noted, seniors who were younger, more active and generally in better health were more likely to be vaccinated.

Shots recommended

The current dispute among experts should not sway seniors inclined to get the shot from doing so. With a vaccine that is safe and easy to get — this year at least — some protection against flu is better than none at all. (Many people don’t seem to know that a dose of pneumococcal would benefit them as well.)

Several studies have pointed to the need for community groups, hospitals and nursing homes to step up their efforts to vaccinate frail and elderly patients at highest risk of dying if they contract the flu.