Swiss public health measures associated with reduced SARS-CoV-2 transmission using genome data.

Nadeau, Sarah A; Vaughan, Timothy G; Beckmann, Christiane; Topolsky, Ivan; Chen, Chaoran; Hodcroft, Emma; Schär, Tobias; Nissen, Ina; Santacroce, Natascha; Burcklen, Elodie; Ferreira, Pedro; Jablonski, Kim Philipp; Posada-Céspedes, Susana; Capece, Vincenzo; Seidel, Sophie; Santamaria de Souza, Noemi; Martinez-Gomez, Julia M; Cheng, Phil; Bosshard, Philipp P; Levesque, Mitchell P; ... (2023). Swiss public health measures associated with reduced SARS-CoV-2 transmission using genome data. Science translational medicine, 15(680), eabn7979. American Association for the Advancement of Science 10.1126/scitranslmed.abn7979

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Genome sequences from evolving infectious pathogens allow quantification of case introductions and local transmission dynamics. We sequenced 11,357 severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) genomes from Switzerland in 2020 - the sixth largest effort globally. Using a representative subset of these data, we estimated viral introductions to Switzerland and their persistence over the course of 2020. We contrasted these estimates with simple null models representing the absence of certain public health measures. We show that Switzerland's border closures de-coupled case introductions from incidence in neighboring countries. Under a simple model, we estimate an 86-98% reduction in introductions during Switzerland's strictest border closures. Furthermore, the Swiss 2020 partial lockdown roughly halved the time for sampled introductions to die out. Last, we quantified local transmission dynamics once introductions into Switzerland occurred, using a phylodynamic model. We found that transmission slowed 35-63% upon outbreak detection in summer 2020, but not in fall. This finding may indicate successful contact tracing over summer before overburdening in fall. The study highlights the added value of genome sequencing data for understanding transmission dynamics.

Item Type:

Journal Article (Original Article)


04 Faculty of Medicine > Pre-clinic Human Medicine > Institute of Social and Preventive Medicine (ISPM)

UniBE Contributor:

Hodcroft, Emma Britt


600 Technology > 610 Medicine & health
300 Social sciences, sociology & anthropology > 360 Social problems & social services




American Association for the Advancement of Science


[4] Swiss National Science Foundation




Pubmed Import

Date Deposited:

09 Nov 2022 09:47

Last Modified:

31 Jan 2023 17:45

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