deconditioning, which is a change in physical function due to bed rest or inactivity.inflammation or a reaction from the immune system.a reduced or lack of response from the immune system.Researchers are not certain what causes the prolonged effects of COVID-19, but some possible causes of long COVID may include: Some evidence also suggests that many people with long COVID are healthcare workers. It also notes that individuals who experience more than five symptoms during the first week of illness are more likely to develop long COVID. Using a statistical model, a preprint 2020 study found that long COVID is more likely to occur in older adults, people with a higher body mass index (BMI), and females. This is consistent with a 2020 study from Italy that found that 87.4% of COVID-19 patients reported experiencing at least one symptom 2 months after their discharge from the hospital.Ī 2020 Swiss study also notes that as many as 1 in 3 people with milder cases COVID-19 were still experiencing symptoms after 6 weeks. One 2021 study found that more than three-quarters of COVID-19 patients in a hospital in Wuhan, China, still had at least one symptom 6 months after their discharge from the hospital. This means that across the world, there may be more than 5 million cases of long COVID. Mounting evidence suggests that many people may continue to experience symptoms related to COVID-19 long after their initial infection with the SARS-CoV-2 virus.Īlthough it is still unclear how many people have experienced long COVID, data from the COVID Symptom Study app suggest that 1 in 10 people with the illness experience symptoms for 3 weeks or longer.ĭata from the United Kingdom’s Office for National Statistics found similar results, with roughly 1 in 10 respondents who tested positive for COVID-19 exhibiting symptoms lasting for a period of 12 weeks or longer. In contrast, over 90% of people discharged from the hospital with influenza usually recover within 2 weeks. This is also true for young adults with no chronic medical conditions.
A 2020 survey by the Centers for Disease Control and Prevention (CDC) suggests that it may take weeks for COVID-19 symptoms to resolve and for people to return to their usual state of health.