The persistence or development of new symptoms three months after the initial acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) infection is referred to as post-coronavirus disease (COVID) condition (PCC). The identification of new biomarkers specific for the occurrence of PCC is vital to proceed in the future towards prediction of its evolution. This study was registered with ISRCTN Registry during recruitment (ISRCTN27312680), and it was conducted comparing two parallel groups: individuals diagnosed with PCC versus individuals who completely recovered within 3 months after acute COVID-19. All participants were enrolled between the first semester of 2022 in Primary Health Care Centers (PHCCs) of Zaragoza (Spain). The two parallel groups were matched by age, gender, and date of acute COVID-19 diagnosis. The diagnosis of PCC was determined by a general practitioner, following the WHO criteria [7], before or at the time of inclusion in the study. Recovered individuals were required to have passed acute COVID-19, confirmed by RT-qPCR, antigen test, or SARS-CoV-2 serology.

This study has been funded by Health Institute Carlos III (ISCIII) through the research grants FIS PI22/01070 and by the European Regional Development Fund (EDRF) "A way of making Europe".