Fig. 4From: Evaluating methodological approaches to assess the severity of infection with SARS-CoV-2 variants: scoping review and applications on Belgian COVID-19 dataOverview of the different selection steps to obtain the study population of Belgian hospitalized COVID-19 patients registered in the Clinical Hospital Surveillance (CHS). This study population has been used to study the severity of SARS-CoV-2 variants. Selecting study participants can introduce selection biasBack to article page