As part of the study, which was published in the International Journal of Epidemiology, Jackson’s team reviewed eight years of medical records from nearly 74,000 members of a local health maintenance organization (HMO). The members were at least 65 years of age. Jackson examined the rate of death and hospitalizations over a full 12-month period.
In every year studied, the risk of death from any cause was lowest before the flu season and then increased progressively through the winter months and later that summer. Compared to those who were not vaccinated, seniors who received the vaccine had a lower rate of death and hospitalizations from pneumonia-like complications before the flu season. The decrease in death rate prior to flu-season makes it difficult for researchers to associate the benefits of the vaccine
As part of a separate study published in the same journal, Jackson found that older people who had medical conditions that made it difficult to get around were less likely to get flu shots. What this may suggest, Jackson said, is that the perceived benefits from the vaccine may not apply to those who are already unhealthy.
"There is a large group of terminally ill patients who are going to die," she said. "We can’t tell how effective the vaccine is."
In an accompanying editorial, Drs. Paul Glezen and Lone Simonsen contend that better vaccines are clearly needed. Until then, other strategies should be considered to help further protect the old and sick. "Immunization of school children," they write, "will reduce exposure of vulnerable patients."
Jackson said that inoculating kids may not be as easy as having seniors line up for shots. But the benefits are increasingly apparent.
"This is starting to fit together," Jackson said. "If you can prevent the flu in one high risk group, you can stop it from spreading outwards.