Truong Nguyen Phuoc, Kant Ravi, Van den Broeck Frederik, Suvanto Maija T, Alburkat Hussein, Virtanen Jenni, Ahvenainen Ella, Castren Robert, Hong Samuel L, Baele Guy, Ahava Maarit J, Jarva Hanna, Jokiranta Suvi Tuulia, Kallio-Kokko Hannimari, Kekäläinen Eliisa, Kirjavainen Vesa, Kortela Elisa, Kurkela Satu, Lappalainen Maija, Liimatainen Hanna, Suchard Marc A, Hannula Sari, Ellonen Pekka, Sironen Tarja, Lemey Philippe, Vapalahti Olli, Smura Teemu
Department of Virology, Faculty of Medicine, University of Helsinki, Helsinki, Finland.
Department of Veterinary Biosciences, Faculty of Veterinary Medicine, University of Helsinki, Helsinki, Finland.
Commun Med (Lond). 2022 Jun 10;2:65. doi: 10.1038/s43856-022-00130-7. eCollection 2022.
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has caused millions of infections and fatalities globally since its emergence in late 2019. The virus was first detected in Finland in January 2020, after which it rapidly spread among the populace in spring. However, compared to other European nations, Finland has had a low incidence of SARS-CoV-2. To gain insight into the origins and turnover of SARS-CoV-2 lineages circulating in Finland in 2020, we investigated the phylogeographic and -dynamic history of the virus.
The origins of SARS-CoV-2 introductions were inferred via Travel-aware Bayesian time-measured phylogeographic analyses. Sequences for the analyses included virus genomes belonging to the B.1 lineage and with the D614G mutation from countries of likely origin, which were determined utilizing Google mobility data. We collected all available sequences from spring and fall peaks to study lineage dynamics.
We observed rapid turnover among Finnish lineages during this period. Clade 20C became the most prevalent among sequenced cases and was replaced by other strains in fall 2020. Bayesian phylogeographic reconstructions suggested 42 independent introductions into Finland during spring 2020, mainly from Italy, Austria, and Spain.
A single introduction from Spain might have seeded one-third of cases in Finland during spring in 2020. The investigations of the original introductions of SARS-CoV-2 to Finland during the early stages of the pandemic and of the subsequent lineage dynamics could be utilized to assess the role of transboundary movements and the effects of early intervention and public health measures.
自2019年末出现以来，严重急性呼吸综合征冠状病毒2（SARS-CoV-2）已在全球范围内导致数百万例感染和死亡。该病毒于2020年1月在芬兰首次被检测到，随后在春季迅速在民众中传播。然而，与其他欧洲国家相比，芬兰的SARS-CoV-2发病率较低。为了深入了解2020年在芬兰传播的SARS-CoV-2谱系的起源和更替情况，我们调查了该病毒的系统地理学和动态历史。
通过基于旅行感知的贝叶斯时间测量系统地理学分析推断SARS-CoV-2引入的起源。分析序列包括来自可能起源国的属于B.1谱系且具有D614G突变的病毒基因组，这些起源国是利用谷歌移动数据确定的。我们收集了春季和秋季高峰期间所有可用序列以研究谱系动态。
在此期间，我们观察到芬兰谱系的快速更替。20C分支在测序病例中成为最普遍的，在2020年秋季被其他毒株取代。贝叶斯系统地理学重建表明，2020年春季有42次独立引入芬兰，主要来自意大利、奥地利和西班牙。
2020年春季，来自西班牙的一次引入可能导致了芬兰三分之一的病例。对大流行早期SARS-CoV-2引入芬兰的原始情况以及随后的谱系动态进行调查，可用于评估跨境流动的作用以及早期干预和公共卫生措施的效果。
