Experts have long known that there’s a connection between certain infections and cardiovascular health. People with heart disease or a history of stroke are at heightened risk of becoming severely ill if they contract infections such as the flu, Covid, or respiratory syncytial virus (RSV), and those infections are capable of triggering sudden cardiovascular “events”—including heart attacks and strokes.
Accordingly, the American College of Cardiology and American Heart Association encourage people with cardiovascular disease to get all of the standard vaccinations recommended for adults. ACC/AHA guidelines also explicitly recommend certain immunizations—namely, those against the seasonal flu, pneumococcal disease, and Covid—as a way to lower the risk of cardiovascular complications from those infections.
Now a recent consensus statement from the European Society of Cardiology (ESC), published in the European Heart Journal at the end of June, is throwing a spotlight on the issue—calling routine vaccinations the “fourth pillar” of cardiovascular protection, along with medications for high blood pressure, high cholesterol, and diabetes.
Here’s a rundown of what you should know about vaccines and your heart, including some of the latest research findings.
The problem with infections
There are various ways that infections can spell trouble for your cardiovascular system, but experts believe that a key route is inflammation. Infections, and your immune response to them, generate inflammation throughout the body. When there is inflammation in the blood vessels, that can worsen symptoms of an existing heart condition or trigger the formation of blood clots that cause a heart attack or stroke. Infections can also directly induce physiologic stress on the heart, which could lead to an arrhythmia or heart failure in an already compromised heart. In addition, respiratory infections like the flu or Covid can reduce the amount of oxygen circulating in the blood and cause spikes in heart rate and blood pressure—all of which puts extra demands on the heart.
How big are the risks?
The risk of suffering an infection-related cardiovascular complication varies from person to person. But some recent research gives an idea of the average risks. One study, published last year in NEJM Evidence, found that among over 23,000 people who tested positive for influenza, the risk of suffering a heart attack within a week of that diagnosis was six times higher, versus the one-year period before or afterward.
A similar pattern has been seen with severe cases of RSV and with pneumococcal disease, a bacterial infection that can lead to pneumonia, blood infections, or meningitis (inflammation of the tissue covering the brain and spinal cord). For example, a 2024 study published in JAMA Internal Medicine found that among adults ages 50 and older who were hospitalized with RSV, nearly one-quarter had an acute heart complication—most commonly an episode of heart failure (where the heart’s pumping ability suddenly declines).
Then there’s Covid. As the new ESC statement points out, experts have known since the early days of the pandemic that Covid (especially severe cases) can lead to heart complications or stroke. That was particularly true during the first pandemic year, when people lacked immune defenses against SARS-CoV-2 (before they built up immunity from prior infections or vaccinations). A study in The Lancet of nearly 87,000 people who contracted Covid in 2020 found that the risks of heart attack and stroke were elevated nearly sevenfold, on average, for two weeks after the infection.
The benefits of vaccinations
Those are some of the risks. How effective are vaccines at lowering them? The most evidence is for flu vaccination, where a number of studies have pointed to benefits. One analysis, published in JAMA Network Open in 2022, pooled the results of six clinical trials that focused on people at increased risk of flu-related cardiovascular complications (due to a recent heart attack or hospitalization for heart failure, for example). Trial participants were randomly divided into two groups—one that received a seasonal flu shot, and another that got a matching placebo or just standard care. Overall, those given the flu shot were about one-third less likely to suffer a heart attack, stroke, heart failure, or severe chest pain over the next year (3.6 percent of those who were vaccinated had such an event, versus 5.4 percent of those who were unvaccinated).
As for other routine immunizations, much of the evidence comes from observational studies. That means researchers tracked the outcomes of people who chose to be vaccinated versus those who didn’t. Those types of studies are not as strong as clinical trials, where (as in the flu studies described above) researchers randomly assign people to be vaccinated or not. That said, there is a strong suggestion that these vaccinations offer some cardiovascular protection:
- Covid vaccination: A 2024 study in Nature Communications, of 46 million adults in England, found that the average risks of heart attack and stroke declined after the first dose of the Covid vaccine, and further dipped after the second dose. A U.S. study published in the Journal of the American College of Cardiology in 2023 had similar results: Among nearly 2 million people who contracted Covid during the first two years of the pandemic, those who had been fully vaccinated were 41 percent less likely to suffer a cardiovascular complication than those who had remained unvaccinated. And even partial vaccination (just one dose) was linked to some protection.
- Pneumococcal vaccination: A 2022 analysis of 15 studies, published in the Journal of Clinical Medicine, found that people who had received the pneumococcal vaccine were about one-quarter less likely to suffer a heart attack or die from any cause over the next six months to several years, compared with unvaccinated people.
- Shingles vaccination: Shingles is yet another vaccine-preventable disease that’s linked to increased cardiovascular risks. A study published in August in Clinical Infectious Diseases found that adults ages 50 and older who had received the two-dose Shingrix vaccine were 28 to 43 percent less likely to be hospitalized for a heart attack or stroke over the next several years, versus unvaccinated people in that age group.
- RSV vaccination. While severe RSV is clearly linked to cardiovascular trouble, the vaccines against the virus are so new (approved within the past two years) that there’s less published research on how well they ward off cardiovascular complications. A large clinical trial called DAN-RSV, in JAMA in August, provided some encouraging news, however: It found a 10 percent reduction in hospitalizations for cardiorespiratory disease during one RSV season among more than 65,000 adults ages 60 and older who had been vaccinated, compared to a similar number who were not. Cardiorespiratory disease includes not only cardiovascular complications but also serious lung conditions like pneumonia. While vaccinated participants had a slightly lower rate of hospitalizations for cardiovascular disease, specifically, the difference between the groups was not significant in statistical terms. Additional (and longer-term) studies are still needed. What’s clear is that RSV vaccination is highly effective at preventing severe infections, which is why one-time vaccination is recommended for all adults ages 75 and older, and those 50 to 74 who are at increased risk of severe RSV (as well as during pregnancy, to protect the newborn).
BOTTOM LINE: Whether you have known cardiovascular disease or not, evidence is growing that getting routine vaccinations will not only reduce your risk of falling severely ill from common infections, but it may also reduce your risk of suffering a heart attack or stroke. If you’re not up to date on vaccinations, or aren’t sure if you are, now is the time to talk to your primary care doctor.
