The Evolution of COVID-19: A Minimal Invasive Autopsy Cohort Studying in Depth the Different COVID- 19 Disease Stages

Abstract Background The WHO defines different COVID-19 disease stages, where pathophysiological mechanisms differ. Clinical, radiological, histological, microbiological, and immunological characteristics of different COVID-19 disease stages were evaluated. Methods Forty-four PCR-confirmed COVID-19 patients were included in a prospective minimal invasive autopsy cohort. Patients were classified according to WHO disease classification in mild-moderate (n=4), severe-critical (n=32) and post-acute disease (n=8) and clinical, radiological, histological, microbiological, and immunological data were compared. Results Classified according to Thoracic Society of America, patients with mild-moderate disease had no typical COVID-19 images on CT-Thorax versus 71.9% with typical images in severe-critical disease and 87.5% typical images in post-acute disease (p<.001). Diffuse alveolar damage was absent in mild-moderate disease but present in 93.8% and 87.5% of patients with severe-critical and post-acute COVID-19, respectively (p=.002). Other organs with histopathological changes were liver and heart. Interferon-g levels were significantly higher in patients with severe-critical COVID-19. Overall, 72% of patients had positive anti-SARS CoV-2 IgM and 51% positive IgG. Conclusion Significant differences in pathological and immunological characteristics between patients with mild-moderate disease compared to patients with severe-critical disease were found, whereas differences between patients with severe-critical disease and post-acute disease were limited. This emphasizes the need for tailored treatment of COVID-19 patients.