Objectives: Post Acute Sequele of COVID-19 (PASC) is a remaining health concern after the pandemic. We aimed to investigate the prevalence of diagnoses and symptom diagnoses recorded before and during the pandemic in individuals who later received PASC. Methods: A case-control study was designed to investigate the prevalence of registered diagnoses in adult, non-hospitalized PASC patients (cases) 2019, 12 months before and 6 months after the PASC diagnosis compared to matched controls. Data was extracted from the Stockholm Region's data warehouse (VAL). Results: Results indicate higher diagnosis rates for men and women with PASC already in 2019 and 12 months before diagnosis; slightly decreasing 6 months after PASC. Cases showed more pre-pandemic respiratory diagnoses compared to controls. In 2019, cases had higher rates of acute upper respiratory tract infection (OR 2.47 for men, 2.22 for women), asthma (OR 1.76 (men), 1.95 (women)), and bronchitis (OR 2.15 (men), 2.71 (women)) than controls. Conclusions: The present study showed that individuals who later developed PASC were more likely than others to show respiratory symptoms before COVID-19. Pre-existing vulnerabilities observed before the pandemic in those later diagnosed with PASC in 2021 suggest a potential link between prior conditions and PASC development.

The authors have declared no competing interest.

This study was funded by Region Stockholm FoUI-97300, Swedish Heart-lung foundation, and Swedish Research Council.

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