COVID-19, the disease caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), emerged in 2019 and caused a global pandemic [1]. Common initial signs and symptoms include cough, fever, fatigue, headache, muscle aches and pain, and diarrhea [2]. Some individuals with COVID-19 become severely ill, usually starting about 1 week after symptom onset; severe COVID-19 often involves progressive respiratory failure and may also result in life-threatening pneumonia, multiorgan failure, and death [2,3]. In addition, many individuals who have had COVID-19 report symptoms of post-acute sequelae of COVID (including breathlessness, cough, fatigue, muscle aches and weakness, sleep difficulties, and cognitive dysfunction), commonly known as long COVID, for weeks, months, or years after the acute stage of illness has passed [4-8]. The risk of long COVID appears to be higher in people who are hospitalized following SARS-CoV-2 infection compared with those who have less severe disease. It also appears to be higher in those who are not vaccinated against COVID-19 compared with those who are vaccinated [4].

https://ods.od.nih.gov/factsheets/COVID19-HealthProfessional/