The prevalence of SARS-CoV-2 infections in preschool and school children is an important benchmark for deciding whether to open kindergartens and schools. The screening study ‘Fr1da’ led by Anette-Gabriele Ziegler tests children in Bavaria for an early stage of type 1 diabetes. These tests include the collection of blood samples. In response to the COVID-19 pandemic, the researchers had decided to use the valuable study infrastructure of the Fr1da study to detect SARS-CoV-2 infections, too. For this, they developed a SARS-CoV-2 antibody test with particularly high accuracy. During the first wave in Germany in spring 2020, the researchers detected a SARS-CoV-2 antibody frequency of 0.87 percent in the children who took part in the Fr1da study. This means that six times more children in Bavaria were infected with the coronavirus than reported via PCR tests (link to press release).