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