Recent Covid vaccinations are showing significant heart health benefits, as indicated by a new study. The research highlights a decrease in the risk of heart attacks, strokes, hospitalizations, and mortality among vaccinated individuals.
The study, which appeared in JAMA Internal Medicine, was published alongside several other Covid-related articles. It examined more than a million veterans who received flu shots at Veterans Affairs facilities in 2024, with about one-third also receiving a Covid vaccine.
It’s established that SARS-CoV-2 infection increases the risk of adverse cardiac events. In the eight months following vaccination, the study found that those who received Covid vaccines (whether mRNA or another type) had a 38% lower risk of major cardiovascular events linked to Covid. This protective effect was most pronounced in individuals aged 75 and older and those with chronic conditions such as kidney and lung disease.
Unexpectedly, the study also noted a 24% reduction in all-cause cardiac events, unrelated to a documented Covid diagnosis. The authors estimate this could prevent around 3,500 major cardiac events and 2,400 deaths per year per million people.
Ziyad Al-Aly, a doctor and clinical researcher at Washington University in St. Louis who led the study, attributes this to higher Covid infection rates in the general population. He explained to STAT that individuals who felt unwell but did not test for Covid could later present with cardiovascular events, suggesting these events were linked to undiagnosed SARS-CoV-2 infections.
Robert Califf, a cardiologist and former FDA commissioner, wrote an accompanying commentary on these findings. He discussed with STAT how Covid vaccination might protect heart health, highlighting that numerous studies have shown vaccines can reduce the risk of chronic diseases, including cardiovascular disease. He also noted the challenges in confirming who has had a subsequent infection due to changes in testing environments.
Al-Aly emphasized to STAT that Covid remains widespread within the population. Despite perceptions that the threat has diminished, he stated that SARS-CoV-2 continues to circulate, often unrecognized, leading to heart issues that aren’t always linked to the virus due to a lack of testing.
While the cardioprotective benefits of Covid vaccines are notable, some may find these results surprising given early concerns about vaccine-related myocarditis, which primarily affected young men. However, studies suggest vaccine-related myocarditis is significantly milder than myocarditis from a Covid infection.
Researchers have identified several potential links between Covid and heart health, such as inflammation and direct heart tissue damage caused by the virus. Infection also raises the risk of long Covid. However, Covid vaccine uptake among older adults is less than half that of flu vaccines.
Califf expressed concern about the low vaccination rates among high-risk populations, suggesting that people do not see it as a medical necessity. He noted the lack of large randomized trials to clearly demonstrate the risks and benefits of vaccinations.
Another study in JAMA Internal Medicine, led by Ryan Wiegand and CDC researchers, assessed the effectiveness of 2024-2025 Covid vaccines in the U.S. Vaccinated individuals showed reduced odds of Covid-related emergency room or urgent care visits, with 41% effectiveness against critical illness for those 18 and older.
Bill Hanage, an epidemiology professor at Harvard University, noted that the short-term effectiveness of Covid vaccines in the Wiegand study is comparable to flu vaccines. He remarked that influenza has only recently surpassed Covid as the leading respiratory illness cause in the U.S., pointing out the effectiveness of Covid vaccines in keeping people out of hospitals.
A study funded by the European Centre for Disease Prevention and Control, published in JAMA Network Open, mirrored these findings for older European adults. The research showed about 55% effectiveness in preventing symptomatic disease in the two months following vaccination. Despite declining vaccine uptake in Europe, researchers emphasized that updated vaccines are more effective against circulating strains, indicating missed opportunities to prevent symptomatic Covid-19 among unvaccinated vulnerable groups.
Regarding individual decisions on Covid vaccination, Califf told STAT that for those skeptical or unsure about vaccines, the benefits might seem minor on an absolute scale for low-risk individuals. However, he stressed that evidence supports that benefits outweigh risks, recommending updates for those at high risk.
Al-Aly also advised individuals to assess their own risks and benefits regarding vaccination, particularly concerning heart health, stating that skipping vaccinations means missing out on substantial protection.
