It is inconclusive whether COVID-19 is a trigger of autoimmunity or an autoimmune condition itself, and further research is being conducted to determine an answer.
Similarities between COVID-19 and autoimmune conditions include the presence of autoantibodies, B cell mobilization, and the potential efficacy of autoimmune medications for treating COVID infections.
Studies on the effects of COVID-19 on individuals with autoimmune diseases have had mixed results, where some studies suggest people with an autoimmune condition have an increased risk of infection or illness while other studies find they do not.
More than 141 million cases of COVID-19 have been confirmed worldwide, and the numbers continue to rise. (Source) Symptoms of the disease may appear within 2 to 14 days after exposure to the virus and vary from person to person. Possible symptoms include:
The pandemic has brought up questions of how autoimmune diseases contribute to the risk of contracting the coronavirus, whether they should be considered serious underlying health conditions in COVID-19 vaccine allocation guidelines, and how individuals with autoimmune conditions can stay safe and healthy. (Source) There is also a growing body of research on the similarities between COVID-19 and autoimmune diseases, and on why some COVID-19 patients go on to develop autoimmune conditions.
Studies on the effects of COVID-19 on individuals with autoimmune diseases or those taking immunosuppressant drugs have had mixed results, with some studies suggesting people with autoimmune diseases are at higher risk for infection and serious illness, and others finding they do not. (Source)
Reports of other coronaviruses causing pneumonia in immunocompromised patients, however, suggest people with autoimmune conditions may be at an increased risk of developing respiratory complications from COVID-19. (Source)
The Centers for Disease Control and Prevention (CDC) Advisory Committee on Immunization Practices informs recommendations on COVID-19 vaccine allocation. The agency suggests vaccines be prioritized for:
COVID-19 vaccination plans based on CDC guidelines differ slightly by state, but autoimmune diseases may be considered underlying medical conditions and allow patients to receive the COVID-19 vaccine in the earlier phases of vaccine allocation.
Leading infectious diseases experts such as Dr. Anthony Fauci, Director of the National Institute of Allergy and Infectious Disease, say that immunocompromised people should get vaccinated as soon as they have the opportunity. (Source)
Immunocompromised people are at risk of complications or vaccine-related disease if they receive certain live or attenuated vaccines, such as the measles, mumps, and rubella vaccine. (Source) However, the Pfizer, Moderna, and Johnson & Johnson COVID-19 vaccines do not contain live viruses. These vaccines are safe for immunocompromised people as long as they don’t have a severe allergy to any of the vaccines’ ingredients. (Source)
COVID-19 and autoimmune diseases may present with similar signs and symptoms. They both stimulate strong immune responses in some people, and some medications used to treat autoimmune conditions may be effective in treating COVID-19. (Source, Source)
Autoantibodies are antibodies that target and attack healthy tissues in the body and cause inflammation, swelling, and damage. These are characteristic of autoimmune diseases, but some of the same autoantibodies found in people with autoimmune diseases have been detected in COVID-19 patients. Additionally, some medications used to treat autoimmune diseases may be effective in treating COVID infections as well. (Source)
A type of immune cell known as B lymphocytes, or B cells, have long been implicated in autoimmune diseases such as systemic lupus erythematosus (SLE). In a normal immune response, B cells secrete antibodies against foreign pathogens, but in SLE they secrete autoantibodies. (Source) A study published in the journal Nature Immunology found “B cell mobilization in COVID-19 is highly similar to the one observed in patients with active autoimmune processes, and in particular with active SLE.” (Source)
Some patients have gone on to develop autoimmune diseases, such as Guillain-Barré syndrome and lupus, after COVID-19 infection. Scientists speculate that SARS-CoV-2 antigens — the proteins on the virus’ surface that antibodies attach to — can trigger an autoimmune response because they closely resemble proteins on the surface of the body’s own cells. (Source)
A small study published in JAMA Cardiology found that 60% of studied patients experienced active myocarditis (inflammation of the middle layer of the heart wall) two months after recovering from COVID-19, even if their infection had been mild. Myocarditis can affect the heart’s ability to pump blood, causing symptoms such as chest pain, shortness of breath, rapid or abnormal heartbeat, and sometimes a fluttering heart. (Source, Source)
John Swartzberg, MD, an emeritus Professor of Infectious Diseases and Vaccinology at the UC Berkeley School of Public Health, shared, “We’re still questioning why we see this inflammation in the heart. One of the hypotheses is that there’s an autoimmune process at work.” He theorizes that SARS-CoV-2 may cause the immune system to misidentify and attack healthy heart cells. (Source)
There is an open question as to whether COVID-19 is an autoimmune condition itself or just a trigger of autoimmunity, and further research needs to be conducted to provide a definitive answer.
Authors of a study published in the Journal of Autoimmunity write, “It seems that COVID-19 shares a similar inflammatory immune response with autoinflammatory and autoimmune conditions.” SARS-CoV-2 may, like an autoimmune disease, cause the immune system to attack healthy tissues. (Source)
In a study published in Clinical Immunology, authors conclude, “We agree with Razim et al., and we feel that our own findings that 21 out of 50 tissue antigens had moderate to strong reactions with the SARS-CoV-2 antibodies are a sufficiently strong indication of cross-reaction between SARS-CoV-2 proteins and a variety of tissue antigens beyond just pulmonary tissue, which could lead to autoimmunity against connective tissue and the cardiovascular, gastrointestinal, and nervous systems.” Although further research needs to be conducted, results indicate that there could be cross-reactivity between SARS-CoV-2 antibodies and the antigens of tissues in the cardiovascular, gastrointestinal, and nervous systems.
COVID-19 infection can have long-term effects on the heart, lungs, and brain.
Symptoms of COVID-19 may persist for months after recovery in what is known as long-haul or long COVID. So-called long haulers can experience:
Follow-up surveys of COVID-19 patients have reported that 50% of 80% experienced persistent symptoms three months after the onset of the disease, even if they had no detectable virus remaining in their bodies. (Source, Source)
Researchers hypothesize that people might experience long COVID because of an autoimmune condition, decreased blood flow to the brain, ongoing inflammation in the brain, or difficulty producing energy to meet the needs of the brain and other organs in the body. (Source, Source)
Dr. Anthony Fauci said that patients post-COVID-19 infection, or those with long COVID, can develop “a post-viral syndrome that's very strikingly similar to myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS).” Symptoms of chronic fatigue characteristic of ME/CFS can arise due to impaired function of the heart, lungs, or kidneys. (Source, Source)
Another possible explanation for these manifestations is that SARS-CoV-2 causes neuroinflammation, inflammation in the brain. Neuroinflammation can cause cytokines, proteins used in cell signalling, to act on a “fatigue nucleus” or conserve energy by limiting their behavior. This conservation of energy allows the body to use the remaining energy stores at its disposal on healing after infection or injury. (Source)
Along with the activation of the “fatigue nucleus” at the hands of neuroinflammation, chronic fatigue and related symptoms can arise from other irregularities found in patients with ME/CFS:
Congress is providing the National Institutes of Health (NIH) $1.15 billion to conduct research into the long-term effects of SARS-CoV-2 infection and long COVID. The proposed name for this phenomenon is Post-Acute Sequelae of SARS-CoV-2 infection, or PASC. (Source) The hope is that further research can elucidate if COVID-19 is an autoimmune condition itself or if it triggers autoimmunity, and that we can learn how to prevent and treat long COVID.