Recent coronavirus vaccinations appear to have broad cardioprotective effects, reducing the risk of heart attacks, strokes, hospitalizations and death in vaccinated people, according to a new study.
The study, published Monday in JAMA Internal Medicine along with several other coronavirus-related papers, followed more than 1 million veterans who received influenza vaccinations at VA medical facilities in 2024. About one-third of them have also received the coronavirus vaccine.
Infection with SARS CoV-2 is known to increase the risk of adverse cardiac events. Researchers found that for eight months after veterans were vaccinated, those who received the coronavirus vaccine (mRNA or another type) had an approximately 38% lower risk of major cardiovascular events related to the coronavirus. The benefits were greatest for people over 75 and people with chronic conditions such as kidney or lung disease.
To the researchers’ surprise, COVID-19 vaccination was also associated with an almost 24% reduction in all-cause cardiac events, not just in patients with a documented diagnosis of COVID-19. The authors said this could prevent about 3,500 serious cardiac events and 2,400 deaths per million people per year.
Ziyad Al Ali, a physician and clinical researcher at Washington University in St. Louis who led the study, argues that this is due to rising rates of coronavirus infection in the broader community. He told STAT about an example of someone who felt “sick” and didn’t get tested for coronavirus at the time, but ended up in the emergency room weeks later with a cardiovascular event. “What this really means is that they (events) are actually likely related to SARS-CoV-2, but were not recognized as such in the first place,” he said.
What happened to the new coronavirus?
Robert Khalif, a cardiologist and former commissioner of the Food and Drug Administration, wrote an accompanying commentary on al-Aly’s findings. Khalif told STAT why COVID-19 vaccinations may protect the heart: “There are now a large number of studies showing that different types of vaccination appear to reduce the risk of chronic disease, including cardiovascular disease…This is consistent with what other studies have shown.” He agreed with Al-Aly, adding: “It’s also worth bearing in mind that the testing environment has changed significantly, so knowing for sure who has subsequently been infected is probably the most unstable of all.”
Al-Aly stressed to STAT that the coronavirus remains prevalent in the general population. “Despite the evolution of the virus, the situation calming down, and the fact that we no longer think of COVID-19 infection as an outcome, the reality is that there is still a tsunami of SARS-CoV-2 that continues to circulate among the population,” he said. “Many of them are just unrecognized and are causing heart disease. Many of them are not linked to or caused by SARS-CoV-2 because people are not being tested.”
Al-Aly’s findings show cardioprotective effects of the coronavirus vaccine, but the results may come as a surprise to some, as vaccine-associated myocarditis, or inflammation of the heart muscle, was an early concern with the mRNA formulation. Side effects were mainly seen in young men. Notably, studies have found that vaccine-associated myocarditis is significantly milder than the myocarditis caused by actual COVID-19 infection.
Researchers say there are multiple potential links between the coronavirus and heart health, including increased inflammation caused by the infection and direct damage to heart tissue by the virus. Infection also increases the risk of COVID-19 and other persistent symptoms. Despite this, the uptake of COVID-19 vaccines among older adults is less than half of the uptake of influenza vaccines.
“In a situation where more than half of the population is not choosing to get an update, even if it’s high risk, people don’t see it as a medical necessity, and the way to prove the risks and benefits would be to do a large randomized trial. I thought the new NIH would be able to answer those questions, but that doesn’t seem to be the case,” Khalif said.
Another new study in JAMA Internal Medicine, led by Ryan Wiegand and researchers at the Centers for Disease Control and Prevention, evaluated the effectiveness of 2024-2025 coronavirus vaccines in the United States. Among vaccinated people, the likelihood of a coronavirus-related emergency room or urgent care visit was reduced. For adults 18 years and older, the vaccine’s effectiveness against severe disease was 41%.
Bill Hanage, a professor of epidemiology at Harvard University who was not involved in the studies, told STAT that he was struck by the Wiegand study’s finding that “the coronavirus vaccine is about as effective as the influenza vaccine in the short term.” He added: “It’s worth mentioning that influenza only recently overtook COVID-19 as the most important respiratory cause of illness and death in the United States, and that was during a pretty bad flu season. COVID-19 vaccines are still protective and are still keeping people out of the hospital.”
A study funded by the European Center for Disease Prevention and Control, also published Monday in JAMA Network Open, showed similar efficacy of coronavirus vaccines in the 2025-2026 season for older adults in Europe. Researchers, including numerous European epidemiologists and public health experts, evaluated individuals aged 60 and older in multiple European countries and found that the vaccine was about 55% effective in protecting participants from symptomatic disease for two months after vaccination. Vaccine uptake is declining in Europe, but the authors told STAT that new annual vaccines are being updated based on “new coronavirus vaccine strains that match circulating viruses and are likely to be more effective.” The study said low vaccination coverage and high efficacy “suggests that unvaccinated vulnerable populations are missing out on the opportunity to prevent symptomatic COVID-19 infection.”
When asked about how individuals should consider their own decisions about getting a coronavirus vaccine, Khalif told STAT, “If you’re the type of person who is skeptical or unsure about vaccines, and the risk is low, then there’s an argument that the benefit is small enough that on an absolute scale it’s not one of the most important health decisions you’ll make.” But he also added, “The evidence shows that the benefits outweigh the risks…My general thought for me and the people I care about is to get the update. Make sure those at high risk get the update.”
Similarly, Al-Aly pointed out to STAT that individuals need to weigh up the pros and cons of vaccination for themselves. When it comes to heart health, especially for older adults and people with comorbidities, “withholding vaccination leaves a lot of protection behind,” he said.
