Before revision: Testing of symptomatic persons for infection with SARS-CoV-2 is increasingly used in different countries. To collect information to understand the causes of the COVID-19 pandemic, we propose two types of case-control studies that can be carried out jointly in test-settings for symptomatic persons.
After revision: Testing of symptomatic persons for infection with SARS-CoV-2 is occurring worldwide. We propose two types of case-control studies that can be carried out jointly in test-settings for symptomatic persons.