A new systematic review and meta-analysis published today in the Journal of the American Heart Association provides compelling evidence that both acute and chronic viral infections significantly increase the risk of cardiovascular events such as heart attack and stroke. The study, which analyzed 155 high-quality studies from around the world, found that the risk of heart attack or stroke can rise three- to five-fold in the month following influenza or COVID-19 infection, while chronic infections like HIV, hepatitis C, and shingles are associated with a persistently elevated risk over many years.
Researchers screened more than 52,000 publications and identified 155 studies for meta-analysis. In studies comparing individuals' cardiovascular risks in the weeks after a documented respiratory infection versus their baseline risk, the data showed that people are four times more likely to have a heart attack and five times more likely to have a stroke within a month of laboratory-confirmed influenza. Similarly, COVID-19 infection was linked to a threefold increased risk of both heart attack and stroke in the 14 weeks following infection, with the risk remaining elevated for up to a year.
The mechanism behind this increased risk involves the immune system's response to viral infections, which triggers inflammation and promotes blood clotting. These effects can persist long after the initial infection resolves, contributing to the formation and rupture of arterial plaques that lead to heart attacks and strokes. According to the American Heart Association, managing inflammation is becoming an important part of preventing and treating cardiovascular disease.
For chronic viral infections, the review found that people with HIV have a 60% higher risk of heart attack and a 45% higher risk of stroke compared to those without HIV. Hepatitis C infection was associated with a 27% higher risk of heart attack and a 23% higher risk of stroke, while shingles (herpes zoster) increased the risk of heart attack by 12% and stroke by 18%. Although these relative risks are lower than those seen with acute infections, the long duration of exposure translates into a substantial population-level burden, especially given that shingles affects about one in three people in their lifetime.
The findings underscore the potential of vaccination to reduce cardiovascular disease. A previous 2022 review of randomized clinical trials found that flu vaccination reduced the risk of major cardiovascular events by 34%. The American Heart Association recommends that individuals, particularly those with existing cardiovascular disease or risk factors, consult with a healthcare professional about appropriate vaccines, including those for influenza, COVID-19, and shingles.
While the connection between viral infections and cardiovascular risk is evident, researchers note that more studies are needed to understand possible links with other viruses such as cytomegalovirus, herpes simplex 1, dengue, and human papillomavirus. The current analysis was limited by its reliance on observational studies, though many adequately accounted for confounding factors. The study was led by Kosuke Kawai, Sc.D., adjunct associate professor at the David Geffen School of Medicine at UCLA, and is published in the Journal of the American Heart Association.
For more information on vaccines and heart health, visit the American Heart Association website. The full manuscript is available online.
