Cytokines (IL1β, IL6, TNFα) and serum cortisol levels may not constitute reliable biomarkers to identify individuals with post-acute sequelae of COVID-19.

Background:Post-acute sequelae of COVID-19 (PASC) comprise a broad spectrum of symptoms such as fatigue, general weakness, compromised attention and sleep or anxiety disorders. PASC represents a medical and socio-economic challenge. Objectives:Our study evaluated cytokines (IL-1β, IL-6 and TNFα) and cortisol levels in a cohort of typical patients with PASC, suffering concentration problems, fatigue and difficulties finding words. Design:This was a prospective cohort study. Four groups were analysed and compared: those who had never contracted SARS-CoV-2 (n = 13), infected but had no PASC (n = 34), infected with former PASC that resolved (n = 40) and patients with ongoing PASC after infection (n = 91). Methods:Cytokine and cortisol serum levels were determined in patients' blood samples. Results:Cytokine levels of IL-1β, IL-6, TNFα and cortisol levels did not differ between groups analysed. Conclusion:This may indicate a non-organic/psychosomatic genesis of PASC; further studies are needed to elucidate the underlying causes of PACS, and non-organic causes should not be overlooked.