KUWAIT CITY, Oct 30: Viral infections, including Covid-19, influenza, and shingles, can significantly raise the risk of heart attack and stroke, according to a new analysis published Wednesday in the Journal of the American Heart Association. The study found that the risk of a heart attack triples within the first few weeks after a COVID-19 infection and quadruples in the month following a flu infection.

The large review, which analyzed more than 150 existing studies, reinforces growing evidence that viral infections are not limited to respiratory illness but have far-reaching impacts on cardiovascular health.

“It endorses a general idea that we’ve been thinking about and talking about for the past several years — that infections are generally not benign,” said Dr. Ziyad Al-Aly, senior clinical epidemiologist at Washington University in St. Louis, who was not involved in the study. “It may start as a respiratory virus, but that’s really the tip of the iceberg, and it has downstream ramifications in multiple organ systems, specifically in this case in the cardiovascular space.”

The review, led by Dr. Kosuke Kawai, associate adjunct professor of medicine at the University of California, Los Angeles, examined the relationship between viral infections and heart disease. Despite variations in study size and methodology, the research consistently showed an association between viral infections and cardiovascular disease, including heart attacks and strokes.

COVID-19 infections were particularly linked to increased cardiovascular risk, most pronounced during the acute infection phase and in severe cases. Some studies suggest that the elevated risk can persist for years after the initial illness. Influenza also showed a strong association, with a fourfold increase in heart attack risk and a fivefold increase in stroke risk during the month following infection.

Chronic viral infections, including hepatitis C, HIV, and varicella zoster (which causes shingles), were associated with long-term increases in heart disease and stroke risk. Other viruses, such as respiratory syncytial virus, human papillomavirus, dengue, and chikungunya, showed more limited but notable links to cardiovascular disease.

“All of these roads lead to Rome,” Dr. Al-Aly said, emphasizing the broader cardiovascular implications of viral infections.

How viruses affect the heart

Experts explain that infections can strain the heart in multiple ways. Acute infections, including bacterial illnesses, can cause fever and elevated heart rate, increasing cardiac stress. In some cases, the heart muscle may not receive sufficient oxygen, leading to a heart attack, said Dr. Daniel M. Musher, professor of medicine at Baylor College of Medicine and the Veterans Affairs Medical Center in Houston.

Long-term effects are largely driven by chronic inflammation. COVID-19, in particular, directly damages the endothelium, the lining of blood vessels in the heart and lungs, causing localized inflammation that can form clots. These clots can block vessels supplying the heart or brain, resulting in heart attacks, strokes, or pulmonary embolism, Dr. Musher explained.

Viruses targeting other organs, such as hepatitis C (liver) or HIV (immune system), also impact cardiovascular health via inflammation. Plaques in arteries contain inflammatory cells that react to systemic inflammation, potentially triggering clot formation and vessel blockage.

Vaccination remains the most effective defense, experts said. Vaccines for influenza, COVID, and shingles reduce both infection rates and severity, which may in turn lower cardiovascular risks.

Having had a viral infection does not guarantee heart disease. High cholesterol, high blood pressure, diabetes, smoking history, and age remain major contributors to cardiovascular risk. Lifestyle changes and medications can mitigate these factors.

Dr. Al-Aly urged people to view viral infection as one of many risk factors. “If it already happened, you cannot undo that,” he said. “Pay attention to the other modifiable risk factors so you can lower your overall risk of cardiovascular disease.”