The Annals of Internal Medicine recently published online a study of the effectiveness of influenza vaccination on the likelihood of subjects 65 and older being hospitalized or dying. The study’s objective was: “To determine the effectiveness of the influenza vaccine in reducing hospitalizations and mortality among elderly persons by using an observational research design that reduces the possibility of bias and confounding.”
The paper reporting data obtained from the United Kingdom is rather densely written and requires a little more effort than usual to decipher, but reaches the conclusion that flu vaccination does not reduce hospitalizations or mortality among elderly people.
The figure below from the study shows hospitalizations against age and mortality rates against age. The breakdown for each curve is shown on the figure. Routine flu vaccination in the UK starts at age 65. As can easily be seen there was no change in the expected rates of hospitalizations or death before or after age 65.
While the conclusions of the authors of this study regarding admission to hospital and death appear substantiated by the data, the finding do not completely exclude a beneficial effect of flu vaccination. The authors are aware of this possibility and discuss it.
The most vulnerable population to hospitalizations and death from the flu or related complications are those who have an ongoing illness and who are immunocompromised. These are the same people who will likely not get a good immune response from vaccination and thus would have the same rate of hospitalization and death before and after vaccination.
Even after considering the scenario just outlined, the authors say their “findings raise questions, however, about the overall effectiveness of a vaccination that is limited to standard vaccines and which focuses too much on elderly persons.” They suggest that a more target approach to the use of the flu vaccine would be a better strategy than vaccinating everyone irrespective of their overall health status.
Such a targeted regimen would certainly save money. It would also likely have no effect on medical outcomes.