Chicago Seniors who receive annual flu shots cut their risk of dying in any given year by at least 24 percent compared with those not vaccinated, according to a Dutch study published Tuesday in the Journal of the American Medical Assn.
The study underscores the dangers posed by the U.S. shortage of flu vaccine if the limited supply is not carefully managed to reach the people at highest risk. The flu and its complications last year killed at least 32,000 elderly people in the United States and 1 million worldwide.
Federal officials say enough vaccine will be available this year for those who really need it. But Dr. Daniel Brauner, a geriatrician and researcher at the University of Chicago, pointed out that, unlike in the Netherlands, many U.S. residents over 65 do not have primary physicians who would help ensure they are vaccinated. Nor do all doctors accept Medicare patients.
"The fact that many people may not have access to flu vaccines this year makes the Dutch study even more poignant," Brauner said.
The study, which examined 26,071 people aged 65 and older, found that annual revaccinations against the flu were much more efficient than single vaccinations at lowering the risk of death from any cause, according to researchers from the Erasmus Medical Center in Rotterdam.
"The most relevant finding from our study is that the more yearly influenza vaccinations a person receives, the lower the mortality rate is in such patients," said the lead author, Bruno Stricker. In fact, the results actually may have underestimated the protective effect of annual revaccination, the researchers said.
An interruption in annual vaccinations -- as might be common among Americans this year because of the shortage -- brought a 25 percent higher risk of death for the following year. However, resuming vaccination after an interruption "brings back protection," Stricker said.
Overall, the researchers estimated that one death was prevented for every 302 vaccinations. Among those who were repeatedly vaccinated, one death was prevented for every 195 vaccinations.