Covid vaccination cut risk of adverse heart events, large study finds
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- Ziyad Al-Aly's study in JAMA Internal Medicine followed over 1 million veterans who received flu shots at VA facilities in 2024, finding that the roughly one-third who also got a Covid vaccine had a 38% lower risk of Covid-associated major cardiovascular events over eight months, with benefits greatest in those 75+ and with chronic kidney or lung disease.
- The researchers also found a surprising nearly 24% reduction in all-cause cardiac events — not just those tied to a documented Covid diagnosis — estimating this could translate to prevention of about 3,500 major cardiac events and 2,400 deaths annually per 1 million people.
- Former FDA Commissioner Robert Califf, writing an accompanying commentary, attributed much of the broader benefit to unrecognized Covid infections, telling STAT that identifying who actually had a subsequent infection is 'probably the shakiest of the whole thing' given how testing has changed.
- A separate CDC-led study by Ryan Wiegand found the 2024-2025 Covid vaccines had 41% effectiveness against critical illness in adults 18+, with Harvard epidemiologist Bill Hanage calling it striking that 'the Covid vaccines are roughly as effective as flu vaccines' over the short term.
- An ECDC-funded European study in JAMA Network Open found approximately 55% effectiveness in protecting adults 60+ from symptomatic Covid in the two months after vaccination, with the authors flagging 'missed opportunities for preventing symptomatic COVID-19 among unvaccinated vulnerable groups' as uptake has fallen.
- Covid vaccine uptake in older adults remains less than half the rate of flu shots, a gap both Califf and Al-Aly said leaves 'a lot of protection on the table' for those at highest cardiovascular risk, with Al-Aly warning that 'a tidal wave of SARS-CoV-2 continues to circulate in the population' largely unrecognized.
Why it matters: For older Americans and those with chronic illness — populations that account for the bulk of cardiovascular mortality — the 38% reduction in Covid-linked heart events and the unexpected 24% drop in all-cause cardiac events translate to thousands of prevented heart attacks, strokes, and deaths per million people, yet fewer than half of older adults are getting the shot. The study reframes Covid vaccination as a cardiovascular intervention, not just a respiratory one, at a moment when the virus continues to circulate widely and silently.
