SARS-CoV-2 Variants of Concern in Switzerland

Different labs across Switzerland perform a genetic characterization of randomly chosen SARS-CoV-2 samples. All these samples stem from swabs of infected people. The goal is to estimate the frequency of the new variants B.1.1.7 (described first in the UK) and 501Y.V2 (described first in South Africa). In each week, the labs report to us the number of considered random samples and the number of identified B.1.1.7 strains and the number of 501Y.V2 strains. We then employ a binomial distribution and Wilson uncertainty intervals in order to estimate the frequency of the variants. Given the delay between infection and swab collection, the frequency estimates for a particular week reflect the epidemic situation around 1-2 weeks earlier. The data is available on Github.

Important: Estimates may be slightly altered retrospectively due to late reporting of cases.

International Comparison

Linear Scale:

Log Scale:

Sources: Denmark: Danish Covid-19 Genome Consortium; UK: GISAID; UK S-dropout: Technical briefings of Public Health England; Switzerland: See acknowledgements belov


Viollier: Samples are provided by Viollier AG. Whole genome sequenicing is performed through the Swiss Viollier Sequencing Consortium lead by ETH Z├╝rich.

Risch: Samples are provided and screened by Labor Risch. Genomic characterization is performed by Labor Risch, the University Hospital Basel (Clinical Mircobiology) and the University Hospitals of Geneva (Group Eckerle and Group Kaiser).