The evidence is clear: COVID-19 infection is risky for the heart.
Nearly three years into the pandemic, study after study has shown that while COVID-19 initially sparked concerns about the lungs, attention is overdue for the heart.
“I think we need to start conceptualizing and thinking of COVID as a risk factor for heart disease,” says Ziyad Al-Aly, a clinical epidemiologist at Washington University in St. Louis.
It’s an important trend to understand as more than 100 million Americans have had COVID-19 – a number that continues to grow each day with no signs of ceasing.
A recent analysis from the American Heart Association found that deaths related to heart disease rose significantly during 2020, the first year of the pandemic. The number of Americans who died from cardiovascular disease jumped from 874,613 deaths in 2019 to 928,741 in 2020 – topping the previous high of 910,000 recorded in 2003.
Perhaps more notable was that the age-adjusted mortality rate, which accounts for changes in the number of older adults in the population from year to year, increased in 2020 for the first time in a decade.
“COVID-19 has both direct and indirect impacts on cardiovascular health,” Michelle Albert, the American Heart Association’s volunteer president, said in a statement. “As we learned, the virus is associated with new clotting and inflammation. We also know that many people who had new or existing heart disease and stroke symptoms were reluctant to seek medical care, particularly in the early days of the pandemic.”
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The pattern has been documented by other groups as well. The Smidt Heart Institute at Cedars-Sinai found in an analysis that deaths from heart attacks rose significantly during COVID-19 surges. The trend was prominent across all age groups but most significant among individuals ages 25-44, which is an age group that is not typically considered at high risk for a heart attack.
“There is something very different about how this virus affects the cardiac risks,” Susan Cheng of the Smidt Heart Institute said in a statement about the study. “The difference is likely due to a combination of stress and inflammation, arising from predisposing factors and the way this virus biologically interacts with the cardiovascular system.”
Another recent study out of the United Kingdom found that individuals infected with COVID-19 had a greater likelihood of several cardiovascular conditions compared with uninfected participants in both the short term and long term, including myocardial infarction, coronary heart disease, heart failure and deep vein thrombosis. The authors suggested that the findings mean that COVID-19 patients should be monitored for at least a year after recovery from infection to diagnose cardiovascular problems.
COVID-19 can affect the heart even if a person’s coronavirus infection is mild. Research from Al-Aly that was published last year found that individuals who were reinfected were twice as likely to die and three times more likely to be hospitalized than those who were infected once. They were also three times more likely to suffer from heart problems.
“However we sliced it with weighted analyses by age and race and sex and prior medical conditions, the risk was everywhere, meaning it really almost did not spare anyone,” Al-Aly says.
Government estimates show that the majority of the U.S. has been infected with the coronavirus. It’s significantly higher than the official number given that infections can be asymptomatic and the results from at-home tests aren’t automatically reported. The high number means more attention needs to shift to those who are getting infected a second, third or fourth time as many experts believe COVID-19 will continue circulating for years to come.
“Reinfection is more and more becoming the norm because most of the people in the U.S. have had it at least once,” Al-Aly says.
That’s why he plans to continue the study to look beyond the one-year mark. He hypothesizes that at some point – he suggests maybe the fifth, sixth or seventh COVID-19 infection – any infection after that point will possibly be just like a cold.
“We expect that ultimately, the risk maybe will flatten with time,” Al-Aly says.
Research on COVID-19’s effect on the heart is expanding, but researchers agree that more attention is needed. A preprint study published on medRxiv last month performed a systematic review of more than 100 studies examining COVID-19 and long-term cardiac symptoms. The high-quality studies that they identified estimated 4% of COVID-19 survivors reported chest pain and nearly 3% reported heart arrhythmia. The authors emphasized that while those percentages seem small, they equate to a lot of people.
“Accumulating evidence shows that long-term cardiac symptoms of COVID-19 are common and can last for months and even beyond one year,” authors wrote in the study.
It’s rare for COVID-19 to directly infect the heart muscle. The virus typically causes issues in other parts of the body that can cause heart damage.
“Even if the virus is not specifically impacting your heart, it could be impacting your lungs or another organ that’s requiring the heart now to work harder to compensate for that,” says Jayne Morgan, a cardiologist and the executive director of health and community education at Piedmont Healthcare in Atlanta.
Much attention has specifically been paid to myocarditis – a condition in which the heart becomes inflamed that is typically a response to a viral infection. Inflammation of the heart can reduce its ability to pump blood to the rest of the body. Most cases are self-resolving and go away within two weeks. But the rare cases that last longer than two weeks are considered chronic and can significantly weaken the heart, leading to heart failure and death.
“When we talk about myocarditis, it can be very, very serious or it can be self limiting,” Morgan says. “So it’s almost the same game of Russian roulette that you’re playing with getting COVID. You can get a very mild form or you can die from it. You just take the risk, so getting multiple infections and getting reinfected and reinfected only increases your risk of finally getting the bullet in the chamber.”
Myocarditis has also been a frequent topic among COVID-19 vaccine skeptics, who have seized on a link between the mRNA shots from Pfizer and Moderna and myocarditis. Recently, skeptics were quick to incorrectly blame the collapse of Buffalo Bills safety Damar Hamlin on the vaccine as he suffered cardiac arrest during a game in January.
And in Florida, the surgeon general last year recommended against the use of mRNA COVID-19 vaccines in men ages 18-39, saying that the “benefit of vaccination is likely outweighed by this abnormally high risk of cardiac-related death among men in this age group.” The decision was slammed by many health officials.
A study out of England last year found that people infected with COVID-19 before receiving a vaccine were 11 times more at risk for developing myocarditis within 28 days of testing positive for the virus. This risk was cut in half for people who had received at least one dose of vaccine.
“Myocarditis is an uncommon condition,” the authors wrote in the study. “The risk of vaccine-associated myocarditis is small, with up to an additional 2 events per million people in the 28-day period after exposure to all vaccine doses other than mRNA-1273. This is substantially lower than the 35 additional myocarditis events observed with SARS-CoV-2 infection before vaccination.”
Al-Aly says it is still important to acknowledge that vaccine injury is real.
“They certainly lead in rare cases to heart problems including, most notoriously, myocarditis,” he says. “But the rates are logs of magnitude lower than the rates of myocarditis, for example, or other heart problems with COVID.”