Flu Shots’ Mortality Protection For Elderly Under Scanner

Flu shots commonly believed to protect the elderly from potentially deadly diseases, especially pneumonia, are currently under the scanner, as a Canadian research team, believing the claims to be over exaggerated, has challenged the widely held view based on its own study.

The flu shot is a vaccine containing killed virus. Injected through a needle, it is usually taken in the arm. It contains three influenza viruses, in their inactivated state. These are - one A (H3N2) virus, one A (H1N1) virus, and one B virus. The flu shot is available as a nasal spray also for those between 2-49 years of age.

All three viruses present in the shot represent the influenza vaccine strains recommended for a year. Anyone who wants can get immunized against flu, but generally people at high risk of getting the disease get themselves vaccinated. However, since the viruses for the vaccine are grown in eggs, people who are allergic to eggs or are having fever, are pregnant or have any respiratory ailment should avoid taking the shot.

While earlier studies had declared a reduction in the “all cause mortality” in the elderly who had taken the shots, the Canadian researchers found this to be an exaggerated finding as they found many factors which were absent in the previous reports, but present in their study group.

They thus concluded in their new research, expected to be published in the first September issue of the- American Journal of Respiratory and Critical Care Medicine, published by the American Thoracic Society; that the “all cause mortality” benefit if present at all was a very small one which could as well be declared statistically, non significant. According to them it was actually a healthy user artefact which they were unable to identify in their research.

"While such a reduction in all-cause mortality would have been impressive, these mortality benefits are likely implausible. Previous studies were likely measuring a benefit not directly attributable to the vaccine itself, but something specific to the individuals who were vaccinated -- a healthy-user benefit or frailty bias," Dean T. Eurich, a clinical epidemiologist and assistant professor at the University of Alberta School of Public Health, said in a university news release.

According to the study's principal investigator, Dr. Sumit Majumdar, an associate professor in the faculty of medicine and dentistry at the University of Alberta: "The healthy-user effect is seen in what doctors often refer to as their 'good' patients -- patients who are well-informed about their health, who exercise regularly, do not smoke or have quit, drink only in moderation, watch what they eat, come in regularly for health maintenance visits and disease screenings, take their medications exactly as prescribed and quite religiously get vaccinated each year so as to stay healthy. Such attributes are almost impossible to capture in large scale studies using administrative databases."

According to the researchers the new findings would now open the possibility of research for stronger and better vaccines, for the elderly, the present one being found not up to the mark as far as effectiveness was concerned; also prompting healthcare agencies and policy makers to work towards the same.