Saint Petersburg Pasteur Institute, 14 Ulitsa Mira, 197101 Saint Petersburg, Russia.
Martsinovsky Institute of Medical Parasitology, Tropical and Vector Borne Diseases, Sechenov First Moscow State Medical University, 119435 Moscow, Russia.
Viruses. 2022 Apr 29;14(5):931. doi: 10.3390/v14050931.
Appearing in Wuhan (China) and quickly spreading across the globe, the novel coronavirus infection quickly became a significant threat to global health. The year 2021 was characterized by both increases and decreases in COVID-19 incidence, and Russia was no exception. In this work, we describe regional features in the Northwestern federal district (FD) of Russia of the pandemic in 2021 based on Rospotrebnadzor statistics and data from SARS-CoV-2 genetic monitoring provided by the Saint Petersburg Pasteur Institute as a part of epidemiological surveillance. The epidemiological situation in the studied region was complicated by the presence of the megacity Saint Petersburg, featuring a high population density and its status as an international transport hub. COVID-19 incidence in the Northwestern FD fluctuated throughout the year, with two characteristic maxima in January and November. An analysis of fluctuations in the age structure, severity of morbidity, mortality rates, and the level of population vaccination in the region during the year is given. Assessment of epidemiological indicators was carried out in relation to changes in locally circulating genetic variants. It was seen that, during 2021, so-called variants of concern (VOC) circulated in the region (Alpha, Beta, Delta, Omicron), with Delta variant strains dominating from June to December. They successively replaced the variants of lines 20A and 20B circulating at the beginning of the year. An epidemiological feature of the northwestern region is the AT.1 variant, which was identified for the first time and later spread throughout the region and beyond its borders. Its share of the regional viral population reached 28.2% in May, and sporadic cases were observed until September. It has been shown that genetic variants of AT.1 lineages distributed in Russia and Northern Europe represent a single phylogenetic group at the base of the 20B branch on the global phylogenetic tree of SARS-CoV-2 strains. The progression of the COVID-19 pandemic occurred against the background of a vaccination campaign. The findings highlight the impact of vaccination on lowering severe COVID-19 case numbers and the mortality rate, despite ongoing changes in circulating SARS-CoV-2 genetic variants.
新型冠状病毒感染症（COVID-19）从武汉（中国）出现并迅速蔓延至全球，迅速成为全球健康的重大威胁。2021 年，COVID-19 的发病率既有增加也有减少，俄罗斯也不例外。在这项工作中，我们根据 Rospotrebnadzor 的统计数据和圣彼得堡巴斯德研究所提供的 SARS-CoV-2 遗传监测数据，描述了俄罗斯西北部联邦区（FD）在 2021 年大流行的区域特征，该研究所作为流行病学监测的一部分。由于存在人口密度高且作为国际交通枢纽的大城市圣彼得堡，研究区域的流行病学情况变得复杂。COVID-19 在该地区的发病率全年波动，1 月和 11 月有两个明显的高峰。本文对该地区全年的年龄结构、发病严重程度、死亡率和人口接种水平的波动进行了分析。对流行病学指标的评估是根据当地流行的遗传变异进行的。结果表明，2021 年在该地区流行的所谓关注变异株（VOC）（Alpha、Beta、Delta、Omicron），Delta 变异株从 6 月到 12 月占主导地位。它们相继取代了年初流行的 20A 和 20B 变异株。该地区的一个流行病学特征是 AT.1 变异株，该变异株首次被发现，后来在该地区及其边界以外传播。其在该地区病毒种群中的比例在 5 月达到 28.2%，直到 9 月仍有散发病例。结果表明，分布在俄罗斯和北欧的 AT.1 谱系的遗传变异株代表 SARS-CoV-2 株全球系统发育树上 20B 分支基部的单一系统发育群。COVID-19 大流行的进展是在接种疫苗运动的背景下发生的。研究结果强调了接种疫苗对降低严重 COVID-19 病例数量和死亡率的影响，尽管循环中的 SARS-CoV-2 遗传变异仍在不断变化。
