Genome sequencing proves it
Lockdown and border closures actually stopped Corona
The lockdown in spring 2020, the border closures and also contact tracing have contributed to the fact that the corona virus has spread less in Switzerland. This has now been proven with genome sequencing.
Published: 12 minutes ago
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Updated: 8 minutes ago
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Iconic picture: On April 25, a Swiss-German couple met near Riehen BS – separated by the border fence.
A new study shows that the border closures, lockdown and contact tracing in Switzerland during the pandemic had an effect. For the study, which was published on Wednesday in the renowned journal “Science Translational Medicine”, more than 11,000 genome sequences of the virus were examined in Switzerland in 2020.
After the borders were closed, around 90 percent fewer infections were imported into Switzerland. These results suggest that the infection process in Germany has been successfully decoupled from abroad, the authors wrote in the study.
Contact tracing halved infections
The lockdown also helped to combat the pandemic: the length of time that introduced viruses persisted in the population during the lockdown was about half as long as after the lockdown was lifted.
When contact tracing worked effectively, it halved the average number of people infected by an infected person. However: For autumn 2020, the researchers could not prove any effect of this contact tracing. “We explain this with the overload of contact tracing during this time,” explains study leader Tanja Stadler (42) from ETH Zurich. Stadler was president of the federal scientific Covid task force from summer 2021 until it was dissolved.
Pathways of infection traced in genes
The results of the study are based on genome sequencing. The “code” of a virus, consisting of 30,000 letters, was decrypted. By decoding this sequence of letters – gene sequencing – it was possible to trace the routes of infection.
The advantage of the study lies in the scope of the data examined. “The fact that these measures were effective has already been shown in qualitative studies. We quantified it based on genomic data,” says Stadler. “It was one of the largest investigations in this area in the world for 2020. Before the pandemic, only a few hundred genes were sequenced for such studies.” (SDA)