![]() Here, we analyze the emergence and spread of the Delta variant in Russia between April-October 2021 and compare it to other countries. Thanks to extensive efforts of many countries in sampling and sequencing SARS-CoV-2 genomes from patients, it is possible to track the spread of different viral variants across the world. Still, adaptive evolution of SARS-CoV-2 in the human genome continues, highlighting the need for surveillance of novel variants. While Delta clearly has increased fitness compared to ancestral strains, whether its sublineages change its properties further is less clear. The phylogeny of Delta is more structured than that of other variants of concern, and its characteristic mutations have accumulated gradually. ![]() Delta has spread rapidly in Russia, increasing in frequency from 1% in April to over 90% in June. The fast spread of Delta may be associated with its reduced sensitivity to neutralization by antibodies as well as increased efficiency of fusion with human cells. It was shown to be more infectious but also to cause higher mortality than earlier variants of concern. ![]() The Delta (B.1.617.2 + AY.*) variant of SARS-CoV-2 that was first detected in India in late 2020 is, as of November 2021, the prevalent lineage in most countries including Russia. While some of these variants are certainly characterized by changed fitness due to changes in transmissibility and/or immune avoidance, much of the geographical difference and dynamics of SARS-CoV-2 lineages is due to epidemiological factors that are not caused by differences in variant fitness. Since the start of the SARS-CoV2 pandemic, several lineages of concern have appeared and replaced preexisting lineages in different countries. Distinguishing between these factors remains challenging in particular, it is difficult to spot the lineages with increased fitness against the background of random frequency fluctuations. In a pandemic, the global spread of viral lineages is defined by a multitude of factors including the intrinsic properties of the virus, properties of host populations, social factors and chance.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |