The study focuses on the recovery of respiratory, cardiovascular and neurological/neuropsychological recovery after intensive care treatment for covid-19. The results will be compared with those obtained from patients treated in the regular wards for covid-19, persons with home treated covid-19 and non-covid controls.

Eligible patients who have been treated in the intensive care units of Helsinki University Hospital are invited to participate. Controls are recruited from follow-up clinics, and with announcements in media and websites.

The participants receive an invitation to a follow-up clinic where their experiences from the ICU treatment and recovery will be discussed. The investigators will perform neuropsychologic testing (6 months post-discharge), a telephone interview (3 months) and send written questionnaires (3, 6 and 24 months) to the participants. The participants will undergo MRI imaging of the brain and laboratory tests will be taken. The olfactory function will be tested at a follow-up clinic. Data on the patients´ respiratory function from clinical spirometry and diffusion capacity testing 3 and 6 months after discharge are collected. The patients will perform a 6 min walk test.

Data on coagulation laboratory values will be registered from acute phase and 6 months after discharge. The investigators will also analyse ApoE alleles, neurofilament light and NAD-metabolites and study their correlation with neuropsychologic findings and long term symptoms (up to 5 years after hospital discharge).

Participants will also undergo magnetic resonance imaging of the heart at 6-12 months after the hospital discharge, and laboratory samples, a symptom questionnaire and electrocardiogram are collected. Inflammatory parameters and variables associated with regulating inflammation and coagulation will be analysed.

Clinical data from the acute and post-acute phase and demographic data are collected from the patient data management systems.

The target patient number is 75 intensive care treated patients and 50 control persons in each three control group.

Inclusion Criteria:

• Age 18-100
• Positive PCR for Sars-CoV-2 (except non-covid controls, who must be negative)
• Native language Finnish or Swedish
• Informed consent to study to study participation

Exclusion Criteria:

• Age under 18
• Pregnant or lactating
• Major neurologic diagnosis (TBI, dementia, stroke, Parkinson´s disease before covid-19)
• Substantially impaired hearing or vision
• Developmental disability.
• No consent to study participation
• Contraindication to MR imaging (such as cardiac pacemaker, allergy to contrast)

Patients who are recovering from critical covid-infection and controls that are either patients recovering from a hospital regular ward treated for covid or covid that has not required hospitalisation. Non-covid controls are age and sex-matched persons (matched to ICU treated group of participants) with no covid-19 in history.