Illustration: Kieran Blakey

The Nuance

Covid-19 Is Looking More and More Like an Autoimmune Disease

Autoimmunity may explain how the virus inflicts such widespread and unpredictable damage

Elemental
Published in
6 min readDec 10, 2020

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Throughout the pandemic, doctors have noticed a confounding phenomenon: A lot of people infected by the coronavirus develop myocarditis, an inflammation of the heart that can cause lasting damage and death.

Even among people who have mild Covid-19 or who are asymptomatic, experts have found evidence of heart inflammation. A July study published in JAMA Cardiology found that 60% of coronavirus patients had active myocarditis two months after their initial infection. Remarkably, the study found that this inflammation was as common among people who recovered at home as it was among those who required hospitalization. (Myocarditis can often go undetected; its symptoms can be subtle and include shortness of breath, chest pain, and a fluttering heart.)

“We’re still questioning why we see this inflammation in the heart,” says John Swartzberg, MD, an emeritus professor of infectious diseases and vaccinology at the UC Berkeley School of Public Health. “One of the hypotheses is that there’s an autoimmune process at work.”

“It seems that Covid-19 shares a similar inflammatory immune response with autoinflammatory and autoimmune conditions.”

“Autoimmunity” describes immune system activity — primarily inflammation — that is directed at healthy cells, tissues, or other inappropriate targets in the body. Autoimmune diseases, such as lupus and multiple sclerosis, are defined by this inappropriate inflammation and its resulting damage. When it comes to Covid-19 and myocarditis, Swartzberg says the autoimmune hypothesis posits that SARS-CoV-2 causes the immune system to misidentify something in the heart’s cells as dangerous. This misidentification leads to inflammation.

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Markham Heid
Elemental

I’m a long-time contributor at TIME and other media orgs. I write mostly about health. I grew up in Michigan, but these days I live in southwest Germany.