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 .
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 causes of the COVID-19 pandemic .