What are the challenges of epidemiological research during the COVID-19 pandemic?

Abstract The COVID-19 pandemic had an impact in several areas, and in scientific research was not different. Researchers are working from their homes since research facilities and universities were closed, and face-to-face interaction where limited to stop the virus spread. This brought a lot of changes in observational studies, especially in epidemiology research. Since most studies are being conducted through internet-based assessments, researchers are facing different challenges regarding data collection and participants recruitment, for example. In this paper, we share some of the challenges faced in a population-based study conducted in Southern Brazil, as well as possible alternatives to help researchers to overcome these issues.