Blog | Friday, March 29, 2013

We're doing it wrong--influenza vaccine edition

This prospective cohort study out of University of Michigan demonstrated that influenza vaccine didn't protect against PCR-documented influenza illness, influenza transmission in households, or medically-attended influenza. Given the good match between vaccine and circulating viruses during the 2010-11 season, and given that the population studied was predominantly healthy young adults and children, these results are pretty shocking (even in the context of other underwhelming data on the effectiveness of influenza vaccination). As John Treanor and Peter Szilagyi opine in the excellent accompanying editorial, "the apparent failure of influenza vaccine under optimal conditions seen in this study is indeed troubling."

One of the more intriguing findings of this study is that receipt of flu vaccine the previous year seemed to reduce the effectiveness of the vaccine, a finding that is not new. What struck me most after reading these two papers, though, was this statement in the editorial: "It is frequently stated that evaluation of influenza vaccines in randomized controlled trials is 'unethical,' but given that the effectiveness of the vaccine is unclear, the subjects in such studies are typically at extremely low risk of serious disease, and that effective antiviral therapy is available, perhaps this statement should be reconsidered."

When a vaccine's effectiveness causes experts to consider a return to randomized controlled trials, it's safe to say that the vaccine in question is pretty awful. We desperately need something better.

Daniel J. Diekema, MD, FACP, practices infectious diseases, clinical microbiology, and hospital epidemiology in Iowa City, Iowa, splitting time between seeing patients with infectious diseases, diagnosing infections in the microbiology laboratory, and trying to prevent infections in the hospital. This post originally appeared at the blog Controversies in Hospital Infection Prevention.