By the end of March 2022, there is a seroprevalence of 97-98% in both cantons Ticino and Zurich and without much difference across the age range. This very high seroprevalence is a result of vaccinations and infections like the recent Omikron wave. In Valais and Vaud, the seroprevalence was slightly lower as the samples were taken before the Omicron wave. In the next testing phase in June/July…