Viral Infections Dramatically Increase Heart Attack and Stroke Risks, Major Study Finds

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 risks in the weeks following acute infections, while chronic viral infections lead to sustained cardiovascular risk over many years.

According to the research, individuals are four times more likely to experience a heart attack and five times more likely to have 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. Both inflammation and increased blood clotting can impair heart function and contribute to cardiovascular events.

Chronic viral infections present a different pattern of risk. 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 elevates heart attack risk by 12% and stroke risk by 18%. These risks persist over an average of more than five years, making them clinically significant despite being lower than the dramatic short-term risks following acute infections.

The findings have important implications for preventive healthcare. Preventive measures against viral infections, including vaccination, may play an important role in decreasing the risk of cardiovascular disease. The researchers cite evidence from a 2022 review showing a 34% lower risk of major cardiovascular events among participants receiving flu vaccines compared to those receiving placebos in randomized clinical trials. The American Heart Association recommends that individuals with cardiovascular disease or risk factors consult healthcare professionals about appropriate vaccinations, as detailed in their health information available at https://www.heart.org/en/health-topics/patient-healthcare-resources/vaccines.

While the study establishes clear links between several common viruses and cardiovascular risk, researchers note that more evidence is needed to understand potential connections with other viruses including cytomegalovirus, herpes simplex 1, dengue, and human papilloma virus. The analysis, based on observational studies conducted primarily in North America, Europe, and East Asia between 1997 and 2024, represents one of the most comprehensive examinations to date of the relationship between viral infections and cardiovascular disease.