Flu and Covid increase the risk of heart attack and stroke

Los Angeles. According to researchers, influenza and coronaviruses significantly increase the risk of acute cardiovascular diseases shortly after infection. For example, the risk of a heart attack or stroke increases four to fivefold after infection with an influenza virus.

In the case of SARS-CoV-2, the risk of a heart attack or stroke increases approximately threefold, as a research team led by Kosuke Kawai from the University of California, Los Angeles, reports in a review study published in the "Journal of the American Heart Association." Other viruses lead to lower, but longer-lasting risks.

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It is now known that human papillomaviruses, hepatitis B viruses, and other viruses can cause cancer. "However, the link between viral infections and other non-communicable diseases such as cardiovascular diseases is less well understood," Kawai is quoted as saying in a statement from the American Heart Association.

He and his colleagues found over 52,000 studies on the relationship between viral infections and cardiovascular diseases in several medical databases from the period 1997 to 2024. Of these, they selected 155 that met their quality requirements and could be made comparable using statistical methods.

The analysis revealed the most significant link between SARS-CoV-2 infections and influenza. The risk of suffering a stroke in the four weeks following the onset of influenza is five times higher than in people without influenza. During the same period, the risk of suffering a heart attack is four times higher. Within four weeks of a SARS-CoV-2 infection, the risk of a heart attack is increased 3.1 times and the risk of a stroke 2.9 times.

The researchers explain the increased risk by saying that the immune system's natural response to viral infections releases substances that trigger inflammation and promote blood clotting, which affects the cardiovascular system.

The analysis also revealed that infection with the human immunodeficiency virus (HIV), which causes AIDS, increases the risk of heart attack by 60 percent and the risk of stroke by 45 percent. The viral disease hepatitis C increases the risk of heart attack by 27 percent and the risk of stroke by 23 percent.

With the varicella-zoster virus (shingles), the increased risk is somewhat lower (heart attack: 12 percent, stroke: 18 percent). All these figures also refer to the period four weeks after infection. "However, the risks associated with these three viruses remain clinically relevant, especially because they persist over a long period; moreover, shingles affects about one in three people during their lifetime," Kawai emphasized.

The study authors advocate for increased vaccination against viruses that can trigger cardiovascular disease. "Prevention is particularly important for adults who already suffer from cardiovascular disease or have risk factors for cardiovascular disease," said Kawai. In the study, the scientists refer to a 2022 review: According to that review, a flu vaccination resulted in a 34 percent lower risk of developing a serious cardiovascular event.

The current study also showed an increased risk of cardiovascular disease with other viruses, such as herpes simplex virus 1, hepatitis A virus, human papillomavirus, and the viruses that cause dengue and chikungunya fever. However, the results were less conclusive than with the viruses mentioned above. The study authors call for further research into the link to cardiovascular disease because these viral infections are widespread globally.

RND/dpa