Many infections with SARS-CoV-2, the virus that causes COVID-19, resolve within days or weeks. But a significant number of people have symptoms that linger for weeks, months, or even years. This is called postacute sequelae of COVID-19 (PASC)—commonly known as “Long COVID.” While several risk factors for PASC have been proposed, we still don’t understand what causes it or why some people get it and others don’t. To further complicate matters, PASC may have different causes in different people.
Some with PASC have changes in certain immune responses, suggesting an immune mechanism for PASC. PASC is particularly common among people with systemic autoimmune rheumatic diseases. These are chronic diseases, such as lupus, where the immune system mistakenly targets the body’s own tissues to cause inflammation. Up to 45% of those with these rheumatic diseases who are infected with SARS-CoV-2 develop PASC.
An NIH-funded research team—led by Drs. Zachary Wallace at Massachusetts General Hospital (MGH), Jeffrey Sparks at Brigham and Women’s Hospital, and Galit Alter at MGH, MIT, and Harvard—examined antibody responses in people with rheumatic diseases who’d had COVID-19. The team measured antibody responses to SARS-CoV-2 and various other pathogens and vaccines. They compared the responses of those who developed PASC with those who didn’t. Results appeared in Science Translational Medicine on September 6, 2023.