Viral Infections Significantly Increase Heart Attack and Stroke Risk, 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 are four times as likely to have 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 a year.

The research team, led by Kosuke Kawai, Sc.D., from the David Geffen School of Medicine at the University of California, Los Angeles, systematically reviewed more than 52,000 publications before identifying 155 high-quality studies appropriate for meta-analysis. The findings demonstrate that the immune system's response to viral infections involves the release of inflammatory molecules and increased blood clotting tendency, both of which can persist long after the initial infection resolves. These mechanisms help explain the heightened cardiovascular risk, as inflammation contributes to plaque formation and rupture in arteries while increased clotting can lead to blockages.

Chronic viral infections also show significant long-term cardiovascular implications. 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%. Kawai emphasized that while these percentage increases are lower than the dramatic short-term risks following acute infections, they remain clinically relevant because they persist over many years and affect large population groups.

The study highlights the potential cardiovascular benefits of vaccination programs. The researchers cite a 2022 review showing a 34% lower risk of major cardiovascular events among participants receiving flu shots in randomized clinical trials compared to those receiving placebos. This suggests that increased vaccination rates for influenza, COVID-19, and shingles could substantially reduce the overall incidence of heart attacks and strokes. The American Heart Association recommends that individuals with cardiovascular disease or risk factors consult healthcare professionals about appropriate vaccinations, as these preventive measures offer critical protection for those already at increased risk.

Although the analysis focused on viruses with substantial public health impact and did not examine high-risk groups such as transplant recipients, the findings underscore the importance of recognizing viral infections as significant cardiovascular risk factors. The research provides compelling evidence that preventive strategies against viral infections, particularly through vaccination, may play a crucial role in reducing cardiovascular disease burden at both individual and population levels.