Common viral infections like flu and shingles can raise your risk of heart attack and stroke, analysis finds

By Asuka Koda, CNN

(CNN) — Covid-19 infections have been strongly linked with cardiovascular conditions like heart disease and stroke, but new research shows that other viral infections such as influenza, HIV, hepatitis C and shingles can also increase the risk of heart problems and cardiovascular disease.

The meta-analysis, published Wednesday in the Journal of the American Heart Association, reviewed 155 studies spanning decades and found that viral infections can raise the risk of heart disease both immediately after an infection and over the long term.

People who caught the flu were up to six times more likely to have a heart attack in the month after the infection, and those who had Covid-19 had nearly twice the risk of developing heart disease or stroke compared with people who hadn’t been infected.

“One way to prevent this is really vaccination,” said lead study author Dr. Kosuke Kawai, an adjunct professor at the David Geffen School of Medicine at the University of California, Los Angeles. “Often, we get vaccinated to reduce the risk of influenza or other illness, but I think vaccines can provide additional benefit in terms of potentially protecting against cardiovascular disease.”

The authors of the new research concluded that influenza and Covid-19 infections were associated with higher risk of acute cardiovascular events such as heart attacks. Chronic viral infections such as HIV, hepatitis C and shingles were associated with a long-­term increased risk of coronary heart disease and stroke.

The new study also notes that cytomegalovirus, herpes simplex, hepatitis A, human papillomavirus (HPV), respiratory syncytial virus (RSV), dengue and chikungunya have been linked to an increased risk of cardiovascular disease, but it says more research on the association is needed.

How does a virus affect the heart?

The new findings fit with what clinicians have long observed, said Dr. Scott Roberts, associate medical director for infection prevention at the Yale School of Medicine.

“Unfortunately, many infections can do this,” he said. “Respiratory viruses increase cardiovascular risk in two ways”: indirectly, by triggering an overactive immune response that causes inflammation, leading to stress and blood clotting that affects the heart; or directly, when the virus can attack heart tissue itself.

Most respiratory viruses, including Covid-19, flu and RSV, act through the indirect pathway, Roberts said, while enterovirus strains – related to the viruses that cause hand, foot and mouth disease – can directly infect the heart muscle.

“Generally, the more severe the viral illness, the greater the risk of cardiovascular complications,” he said. These infections can also worsen existing heart problems like heart failure, he added.

Kawai said it’s hard to quantify how likely it is for someone with a viral infection to develop cardiovascular disease, so everyone should take protective measures.

“It also depends on the viral infection,” Kawai said. “It’s not just the patients who have underlying increased risk for cardiovascular disease that might be at greater risk, but those who are younger adults, or people who might not necessarily have some of the risk factors for cardiovascular disease, are also at increased risk” after a viral infection.

Prevention is key

“Our study highlights the importance of integrated preventive measures, especially for adults with traditional risk factors for [cardiovascular disease]. Vaccines may play an important role in preventing the risk of CVD,” the researchers wrote.

They concluded that preventive measures such as vaccination and timely antiviral treatment could help reduce the burden of cardiovascular disease, which remains the world’s leading cause of death.

“Vaccines for many of these viruses exist and generally lessen the risk of cardiovascular events after infection, since the severe infection is more likely to be mild in a vaccinated individual,” Roberts said.

In people who have a healthy immune system, vaccines are protective without causing cardiovascular disease because they typically contain a small amount of an inactivated virus or specific subunits from the pathogen, Kawai said. The inactivated virus does not trigger an overactive immune response that causes inflammation that affects the heart, nor is it able to attack heart tissues themselves.

Anyone who is concerned about the risk of heart problems after an infection should talk with their doctor, Roberts advises.

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