Before revision: An increasing number of countries expands testing of symptomatic persons for infection with SARS-CoV-2 . It is important to consider efficient ways to collect information that will allow to understand the  COVID-19 pandemic . We propose two types of case-control studies that can be carried out  in test-settings for symptomatic persons.
After revision: An increasing number of countries expands testing of symptomatic persons for infection with SARS-CoV-2 . It is important to consider efficient ways to collect information that will allow to understand the COVID-19 pandemic , we propose two types of case-control studies that can be carried out in test-settings for symptomatic persons.