Lethality of SARS-CoV-2 infection-a comparative autopsy study focusing on COVID-19 development and virus variants

Different SARS-CoV-2 variants are driving various waves of infection of the corona pandemic. Official statistics provide no information on who died due to coronavirus disease 2019 (COVID-19) or an alternative disease during which SARS-CoV-2 infection was detected. The current study aims at addressing the effect of the different variants evolving during the pandemic on fatal outcomes.

Standardised autopsies were performed on 117 people who died of a SARS-CoV-2 infection and the findings were interpreted in clinical and pathophysiological contexts. The typical histological sequence of COVID-19-related lung injury was detected independently of the disease-causing virus variant, but was significantly less common (50 versus 80-100%) and less severe in cases infected by omicron variants compared to precedent variants (P < 0.05). COVID-19 was less often the leading cause of death following omicron infection. Extrapulmonary manifestations of COVID-19 did not contribute to death in this cohort. Lethal COVID-19 may occur after complete SARS-CoV-2 vaccination. Reinfection was not the cause of death in any of the autopsies of this cohort.

Autopsies represent the gold standard in determining the cause of death after SARS-CoV-2 infection and autopsy registers are currently the only available data source allowing for evaluation of which patients died of COVID-19 or with SARS-CoV-2 infection. Compared to previous variants, infection with an omicron variant affected the lungs less frequently and resulted in less severe lung disease.