Post-COVID syndrome - characterization and determination of risk factors in Sweden, Finland and Denmark - Nordic database and biobank data

To authoritatively identify the most common but also more rare clinical features of post-COVID syndrome (PCS), we will combine nationwide registry data from Sweden (COVID-19 patients = 1,507,174), Finland (109,230) and Denmark (323,786).

The ICD-10 diagnosis codes for all visits to the health care system and from medical certificates for sick leave will be determined for visits 3 months after disease onset.

We will determine which individuals are at increased of PCS compared to the whole Swedish population, and which are the most important risk factors (socioeconomic and demographic, occupation, gender and age, and burden of comorbidities) for PCS versus the whole Swedish population.

Similar studies will be performed for Finland and Denmark.Using biobank blood samples (n ≈ 6000 currently) obtained before COVID-19 we will identify circulating biomarkers and genetic risk factors/protective factors that can predict individuals at risk of PCS. Thereby these individuals can be prioritized for vaccines.

The COVID-19 outcome is determined by registry data.Project 1-3 will be performed in parallel during 2022-2025. Collaboration with national and international expertise ensures feasibility of the planned projects.

The planned projects aims to characterize PCS in three nordic countries, identify risk factors and biomarkers associated with PCS. This will increase knowledge for clinicians and thereby increase patient safety and treatment.