A meta-analysis of 155 observational studies ties influenza, COVID-19, hepatitis C, and herpes zoster (shingles) to a dramatically higher risk of major cardiovascular events such as heart attack and stroke in the weeks after infection, and viruses that linger in the body (eg, HIV) can raise long-term risk.

A University of California Los Angeles (UCLA) researcher led the study, a systematic review of literature on the link between any viral infection and the odds of heart attack and stroke. The findings were published last week in the Journal of the American Heart Association (AHA)

“It is well recognized that human papillomavirus (HPV), hepatitis B virus, and other viruses can cause cancer; however, the link between viral infections and other non-communicable diseases, such as cardiovascular disease, is less well understood,” lead author Kosuke Kawai, ScD, of UCLA, said in an AHA news release.

Stroke 5 times more likely after flu

The 155 studies, published from 1997 to July 2024, were primarily conducted in North America, Europe, and East Asia.

Self‐controlled case series studies tied flu to a fourfold elevated risk of heart attack (pooled incidence rate ratio [IRR], 4.01) and a fivefold higher risk of stroke during the first 1 month (IRR, 5.01), and cohort studies suggested a higher risk of coronary heart disease (CHD) with hepatitis C infection (RR, 1.27) and stroke (RR, 1.23). 

HIV was consistently linked to a higher risk of CHD (pooled adjusted risk ratio [RR], 1.60) and stroke (RR, 1.45), as was SARS‐CoV‐2 (CHD RR, 1.74; stroke RR, 1.69). Likewise, shingles was associated with a greater risk of CHD (RR, 1.12) and stroke (RR, 1.18). Evidence of an effect of cytomegalovirus, which can cause birth defects, on cardiovascular disease was insufficient. 

The study authors noted that viral infections trigger the immune system to release substances that lead to inflammation and increase the risk of blood clots, processes that may persist long after initial infection and raise the risk of heart attack and stroke.

“The elevated risks for cardiovascular disease risks are lower for HIV, hepatitis C and herpes zoster than the heightened short-term risk following influenza and COVID,” Kawai said. “However, the risks associated with those three viruses are still clinically relevant, especially because they persist for a long period of time.”

And when it comes to shingles, which affects roughly one in three people in their lifetime, “the elevated risk associated with that virus translates into a large number of excess cases of cardiovascular disease at the population level,” he said.

Vaccines’ role in preventing heart, vascular disease

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