Smaller trials had hinted the flu vaccine itself might protect the heart, not just the lungs, but none were large enough to be sure. Ole Frobert's team at Orebro University ran a trial across eight countries to test the idea in people recovering from a heart attack.
The IAMI trial randomized 2,571 patients hospitalized for a heart attack to an influenza vaccine or a saline placebo. Over the next year, all-cause death occurred in 2.9 percent of the vaccinated group versus 4.9 percent of the placebo group, and the combined rate of death, heart attack, or stent blockage fell 28 percent.
The 41 percent relative drop in deaths was larger than researchers expected from a vaccine for a respiratory virus, fitting a pattern of infections triggering plaque rupture in damaged arteries. The trial alone was not large enough to settle the question, but it lines up with observational data and has pushed cardiology societies to recommend flu vaccination as routine care after a heart attack.
Read the original study
Frobert et al., Circulation, 2021 · doi.org/10.1161/CIRCULATIONAHA.121.057042
A flu shot that protects the heart.
Source
- Fröbert, O., Götberg, M., Erlinge, D., Akhtar, Z., Christiansen, E. H., MacIntyre, C. R., Oldroyd, K. G., Motovska, Z., Erglis, A., Moer, R., Hlinomaz, O., Jakobsen, L., Engstrøm, T., Jensen, L. O., Fallesen, C. O., Jensen, S. E., Angerås, O., Calais, F., Kåregren, A., . . . Pernow, J. (2021). Influenza Vaccination After Myocardial Infarction: A Randomized, Double-Blind, Placebo-Controlled, Multicenter Trial. Circulation, 144(18), 1476–1484. https://doi.org/10.1161/CIRCULATIONAHA.121.057042