Emergence and Persistent Dominance of Omicron BA.2.3.7 Variant in Community Outbreaks in Taiwan (preprint)

ABSTRACT

Using high-throughput sequencing of the SARS-CoV-2 genome, we have analyzed 2405 PCR-positive swab samples from 2339 individuals and identified the Omicron BA.2.3.7 variant as a major lineage of the recent community outbreak in Taiwan. Since April 2022, a series of new waves of Omicron cases have surfaced in Taiwan and spread throughout the island. We conducted genomic surveillance with a high success rate and have submitted 1966 full-length Omicron sequences to GISAID. This has permitted identification of signature amino acid changes (ORF1aL631F, SK97E, NM322I) in 1584 (80.6%) of the translated SARS-CoV-2 sequences. The newly established BA.2.3.7 lineage, which is relatively common in Asian countries, is now persistently present in Taiwan. By June 2022 this dominant strain had established a substantial existence in the sequence pool, resulting in additional mutations. The rapid spread and expansion of the Omicron BA.2.3.7 lineage in Asia has had an important socioeconomic impact on health policy.