A study led by Charité - Universitätsmedizin Berlin and the Max Planck Institute for Molecular Genetics (MPIMG) with support from TU Berlin shows that some healthy people have immune cells that can recognise the novel coronavirus SARS-CoV-2. The reason could be previous infections with common cold coronaviruses. Whether such cross-reactivity has a protective effect on the course of an infection with SARS-CoV-2 is now to be shown in the study "Charité Corona Cross".