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. 2022 Mar;27(10):2200181.
doi: 10.2807/1560-7917.ES.2022.27.10.2200181.

Molecular epidemiology of the SARS-CoV-2 variant Omicron BA.2 sub-lineage in Denmark, 29 November 2021 to 2 January 2022

Jannik Fonager  1 , Marc Bennedbæk  1 , Peter Bager  2 , Jan Wohlfahrt  3 , Kirsten Maren Ellegaard  4 , Anna Cäcilia Ingham  4 , Sofie Marie Edslev  4 , Marc Stegger  4 , Raphael Niklaus Sieber  4 , Ria Lassauniere  1 , Anders Fomsgaard  1 , Troels Lillebaek  5   6 , Christina Wiid Svarrer  4 , Frederik Trier Møller  7 , Camilla Holten Møller  2 , Rebecca Legarth  2 , Thomas Vognbjerg Sydenham  8 , Kat Steinke  8 , Sarah Juel Paulsen  9 , José Alfredo Samaniego Castruita  9 , Uffe Vest Schneider  9 , Christian Højte Schouw  10 , Xiaohui Chen Nielsen  10 , Maria Overvad  7 , Rikke Thoft Nielsen  7 , Rasmus L Marvig  11 , Martin Schou Pedersen  12 , Lene Nielsen  13 , Line Lynge Nilsson  13 , Jonas Bybjerg-Grauholm  14 , Irene Harder Tarpgaard  15 , Tine Snejbjerg Ebsen  15 , Janni Uyen Hoa Lam  7 , Vithiagaran Gunalan  1 , Morten Rasmussen  1
Affiliations

Molecular epidemiology of the SARS-CoV-2 variant Omicron BA.2 sub-lineage in Denmark, 29 November 2021 to 2 January 2022

Jannik Fonager et al. Euro Surveill. 2022 Mar.

Abstract

Following emergence of the SARS-CoV-2 variant Omicron in November 2021, the dominant BA.1 sub-lineage was replaced by the BA.2 sub-lineage in Denmark. We analysed the first 2,623 BA.2 cases from 29 November 2021 to 2 January 2022. No epidemiological or clinical differences were found between individuals infected with BA.1 versus BA.2. Phylogenetic analyses showed a geographic east-to-west transmission of BA.2 from the Capital Region with clusters expanding after the Christmas holidays. Mutational analysis shows distinct differences between BA.1 and BA.2.

Keywords: BA.1; BA.2; COVID-19; Omicron; SARS-CoV-2; variant of concern.

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Conflict of interest statement

Conflict of interest: None declared.

Figures

Figure 1
Figure 1
Transmission of SARS-CoV-2 Omicron variant sub-lineage BA.2 across regions and over time, Denmark, 29 November 2021–2 January 2022 (n = 2,616a)
Figure 2
Figure 2
Mutation profile and structural prediction of SARS-CoV-2 Omicron variant sub-lineage BA.1 (n = 16,137) and BA.2 (n = 2,623) sequences, Denmark, 29 November 2021–2 January 2022
See this image and copyright information in PMC

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Supplementary concepts