The first prototypes of the live-attenuated vaccines were developed at the University of Bern and the Institute of Virology and Immunology (IVI). The study was conducted as part of the Swiss National Science Foundation’s project NRP78 “Recoding the SARS-CoV-2 Genome – A Multidisciplinary Approach to Generate Live-Attenuated Coronavirus Vaccines.” The project has brought researchers from Switzerland and Germany together to evaluate different approaches to recoding the SARS-CoV-2 genome in developing vaccines.