A comprehensive review of 155 scientific studies published in the Journal of the American Heart Association reveals that viral infections significantly increase both short-term and long-term risks of cardiovascular events including heart attacks and strokes. The analysis found that people face dramatically elevated cardiovascular risks in the weeks following acute infections, while chronic viral infections maintain elevated risk over extended periods.
Researchers documented that individuals are four times more likely to experience a heart attack and five times more likely to suffer a stroke in the month following laboratory-confirmed influenza infection. Similarly, COVID-19 infection increases heart attack and stroke risk threefold in the 14 weeks following infection, with elevated risk persisting for up to one year. The study, which screened more than 52,000 publications before selecting 155 high-quality studies for meta-analysis, provides compelling evidence of the cardiovascular consequences of viral infections.
The biological mechanisms behind this increased risk involve the immune system's response to viral invaders. "The immune system's natural response to viral infections includes the release of molecules that trigger and sustain inflammation and promote the tendency of blood to clot, both of which may last long after the initial infection has been resolved," explained lead author Kosuke Kawai, Sc.D., adjunct associate professor at the David Geffen School of Medicine at UCLA. Inflammation contributes to plaque formation and rupture in arteries, while increased blood clotting can compromise heart function.
Chronic viral infections present different but equally concerning cardiovascular risks. The analysis found people with HIV infection face a 60% higher risk of heart attack and 45% higher risk of stroke compared to similar individuals without the infection. Hepatitis C infection increases heart attack risk by 27% and stroke risk by 23%, while shingles (caused by varicella zoster virus) elevates heart attack risk by 12% and stroke risk by 18%. These risks persist for an average of more than five years following infection.
"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. However, the risks associated with those three viruses are still clinically relevant, especially because they persist for a long period of time," Kawai noted. "Moreover, shingles affects about one in three people in their lifetime. Therefore, the elevated risk associated with that virus translates into a large number of excess cases of cardiovascular disease at the population level."
The findings underscore the importance of preventive measures, particularly vaccination. A 2022 review cited in the study found a 34% lower risk of major cardiovascular events among participants receiving flu shots in randomized clinical trials compared to those receiving placebos. "Preventive measures against viral infections, including vaccination, may play an important role in decreasing the risk of cardiovascular disease. Prevention is especially important for adults who already have cardiovascular disease or cardiovascular disease risk factors," Kawai emphasized.
The American Heart Association recommends that individuals with cardiovascular disease consult healthcare professionals about appropriate vaccinations, as these individuals face more severe complications from viral infections. While the current analysis focused on common viral infections affecting the general population, researchers note that more studies are needed to understand potential links between heart disease risk and other viruses including cytomegalovirus, herpes simplex 1, dengue, and human papilloma virus. The study's limitations include its reliance on observational studies rather than randomized controlled trials, though most studies adequately accounted for potential confounding factors. Additional financial information about the American Heart Association is available at https://www.heart.org/en/about-us/aha-financial-information.
