Catching COVID-19 or the Flu Could Triple Your Risk of Stroke and Heart Attack

A bout of COVID-19 or the flu can dramatically increase your likelihood of developing a stroke or experiencing a heart attack, even if you recovered weeks ago.

According to a new paper published in the Journal of the American Heart Association, the risk rises three to fivefold in the weeks and months after a viral infection like influenza. Meanwhile, people living with chronic diseases such as HIV and Hepatitis C face a less severe but longer-term increased risk of cardiovascular disease.

“Our study found acute and chronic viral infections are linked to both short- and long-term risks of cardiovascular disease, including strokes and heart attacks,” said Kosuke Kawai, Sc.D., lead author of the study and adjunct associate professor in the division of general internal medicine and health services research at the David Geffen School of Medicine at the University of California, Los Angeles, in a statement.

Kawai and his team came to this conclusion after reviewing 155 studies published between 1997 and 2024.

Viral Infections: An Acute Risk

The researchers analyzed studies comparing patients in the weeks after COVID-19 and flu infections with those same patients during periods without viral infection.

According to some studies included in the meta-analysis, those diagnosed with COVID-19 were three times as likely to have a heart attack or a stroke in the 14 weeks after the infection and remained at a higher level of risk for a year.

Meanwhile, those with a laboratory-confirmed case of the flu were four times as likely to suffer a heart attack and 5 times as likely to experience a stroke in the month after infection. As the researchers note, those who have undergone laboratory testing are more likely to have had a severe bout of the flu, so the same level of risk may not apply to a milder spell.

Kawai and his team suggest that this increased risk could be linked to the body’s immune response to infection, which triggers inflammation and can increase the likelihood of blood clotting. This, in turn, places more strain on the heart. A state of inflammation could persist after the initial infection, possibly explaining the increased risk in the weeks after illness.

Chronic Conditions: A Milder But Longer-Term Risk

The team also investigated the long-term association between chronic conditions and cardiovascular events, comparing participants with the condition to similar participants without.

The results suggest a significantly higher risk of heart attack and stroke in people with HIV (60 percent and 45 percent), hepatitis C (27 percent and 23 percent), and shingles (12 percent and 18 percent) than those without. While this is not as high as that seen post-viral infection, the researchers highlight its importance as a long-term risk.

“Moreover, shingles affects about one in three people in their lifetime,” said Kawai. “Therefore, the elevated risk associated with that virus translates into a large number of excess cases of cardiovascular disease at the population level.”

The researchers note an association between other conditions, such as herpes, hepatitis A, HPV, and dengue, and an increased risk of cardiovascular disease, but state the link requires further investigation.

A Leading Cause Of Death

Cardiovascular disease is currently the leading cause of death worldwide and in the U.S., where it was responsible for 680,981 deaths in 2023 (11 percent more than the next biggest killer, cancer), according to the Centers for Disease Control and Prevention (CDC).

But, as the researchers point out, there may be steps that can be taken to reduce that risk — one of which is vaccination. According to one of the studies cited in the paper, published in the JAMA Network Open, those who were offered a flu shot were 34 percent less likely to face a major cardiovascular event than those who received a placebo.

This article is not offering medical advice and should be used for informational purposes only.

Read More: Mental Recovery From COVID-19 Symptoms Can Take Up to 9 Months

Article Sources

Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:

• This article references information from the recent study published in the Journal of the American Heart Association: Viral Infections and Risk of Cardiovascular Disease: Systematic Review and Meta‐Analysis
• This article references information from the recent study published in the JAMA Open Network: Association of Influenza Vaccination With Cardiovascular Risk
• This article references information from the Centers for Disease Control and Prevention (CDC): Leading Causes of Death