A wide range of complications have been linked to COVID-19 - the coronavirus disease caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). It is well known that COVID-19 affects multiple organs. Most of the data however present the early complications during the acute phase of the infection, and there is still a lack of knowledge on the late complications that might appear after recovery. Additionally, the long-term complications in patients who were asymptomatic or had mild symptoms during the acute phase of infection, not requiring hospitalization, oxygen therapy or mechanical ventilation has not been fully studied. Therefore, our aim was to assess factors related to the severity of post-COVID complications among patients without severe symptoms in the acute phase of COVID-19. The study will include consecutive COVID-19 convalescents (the infection of coronavirus was confirmed with real-time polymerase chain reaction test or positive result of autoantibodies) admitted to the Departments of Polish Mother Memorial Research Institute (PMMHRI) in Lodz, Poland, for complications. Both children and adults will be included in the study. The patients will have laboratory testing and other studies due to the character of symptoms.
