Genomic epidemiology of the early stages of the SARS-CoV-2 outbreak in Russia

The ongoing pandemic of SARS-CoV-2 presents novel challenges and opportunities for the use of phylogenetics to understand and control its spread. Here, we analyze the emergence of SARS-CoV-2 in Russia in March and April 2020. Combining phylogeographic analysis with travel history data, we estimate that the sampled viral diversity has originated from at least 67 closely timed introductions into Russia, mostly in late February to early March. All but one of these introductions were not from China, suggesting that border closure with China has helped delay establishment of SARS-CoV-2 in Russia. These introductions resulted in at least 9 distinct Russian lineages corresponding to domestic transmission. A notable transmission cluster corresponded to a nosocomial outbreak at the Vreden hospital in Saint Petersburg; phylodynamic analysis of this cluster reveals multiple (2-3) introductions each giving rise to a large number of cases, with a high initial effective reproduction number of 3.0 [1.9, 4.3]. The COVID-19 epidemic began later in Russia than many European countries, possibly due to restrictions on travel from China. Here, the authors analyze whole genome sequences sampled early in the epidemic in Russia, and find that most strains were not linked to China.

Automated summary

The study analyzed the emergence of SARS-CoV-2 in Russia in 2020, finding that of the 67 introductions, only one was from China, indicating that border closure may have helped delay the spread of the virus in Russia.