Symptoms and pathophysiology of post-acute sequelae following COVID-19 (PASC): a cohort study

BACKGROUND: Several studies reported long-term consequences of severe COVID-19. However, pathophysiological mechanisms of Post-Acute Sequelae following COVID-19 (PASC) in patients with mild acute COVID-19 have been less investigated. Specifically, the link between PASC and immuno-inflammatory abnormalities is inconsistent in the literature. The hypothesis that different pathophysiological mechanisms could explain the persistent symptoms needs to be explored. METHODS: The COPER cohort is a prospective study that included participants with PASC and with a history of COVID-19 without persistent symptoms. None were hospitalised for COVID-19. Participants underwent two home visits six months apart for biological sample collection and completed questionnaires on medical history, infection, vaccination, symptoms, and mental health. The study analysed association between persistent symptoms and 14 blood biomarkers, comparing participants with PASC with recovered participants. FINDINGS: Between June and November 2022, 1000 participants were included in the study, 199 were excluded due to missing data or sample (35), SARS-CoV-2 infection less than 3 months (36) or lack of known SARS-CoV-2 infection and negative serology (128), with two groups analysed: recovered (n = 490), PASC (n = 311). Participants with PASC were more frequently women, had a higher BMI and a median number of 3 persistent symptoms, with common symptoms being asthenia, dyspnoea, cough, and sleep disorders. Biological analysis revealed significant associations between certain PACS symptoms and biomarkers of viral activation (IFNγ, IP-10), COVID-19 severity (CD163) and vascular activation (VCAM-1, ICAM-1), mainly in subjects whose symptoms had lasted less than a year. However, these associations did not persist over time. INTERPRETATION: The results suggest a polymorphic and dynamic pathophysiology according to symptoms and time since infection. Other hypotheses, beyond those related to persistent inflammation, should be explored. FUNDING: French Ministry of Health and Prevention and the French Ministry of Higher Education, Research and Innovation.