The COVID-19 infection affects humans differently. While some recover quickly and fully, others develop serious illnesses and late complications. The term late complications describe symptoms that last for 12 weeks or longer after COVID-19 infection is detected. The aim of the present project is to investigate whether it is possible to identify genetic factors that occur more frequently in people suffering from COVID-19 late complications than in those who do not develop late complications. The investigators aim to develop a genetic profile that identifies individuals at high risk for late complications of COVID-19. Number and nature of late complications will be analysed to identify patterns in the incidence of late complications associated with certain genetic traits. The study is designed as a case-control study and is expected to include 500 subjects between 18 and 65 years of age who at least 12 weeks ago tested positive for COVID-19; 250 who suffer from late complications and 250 who have fully recovered.