Surge of Severe Acute Respiratory Syndrome Coronavirus 2 Infections Linked to Single Introduction of a Virus Strain in Myanmar, 2020

Abstract

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection is a major health concern globally. Genomic epidemiology is an important tool to assess the pandemic of the coronavirus disease 2019 (COVID-19). Several mutations have been reported by genome analysis of the SARS-CoV-2. In the present study, we investigate mutational and phylogenetic analysis of 30 whole genome sequences for genomic characteristics of the virus in the specimens collected early phase of pandemic, (March-June, 2020) and sudden surge of infection (August-September, 2020). Phylogenetic analysis revealed that 4 samples of L strain and 1 GR strain in early stage of local transmission, while 6 returnees by rescue flights showed GH (India) and GR strains (China and Philippines) with no evidence of local spread. However, all 19 whole genome sequences in sudden surge of local transmission showed genetically distinct clade GH (Lineage B.1.36). Surge of second wave on SARS-CoV-2 infection was linked to the single-introduction of the GH strain that may be a result of strict restriction of international travel and containment efforts. These genomic data provides the useful information to disease control and prevention strategy.

The SARS-CoV-2 infection in Thailand: analysis of spike variants complemented by protein structure insights

“…A study by Yurkovetskiy et al using cryo-electron microscopy, indeed, confirms that p.D614G disrupts an interprotomer contact, thus facilitating the spike “open conformation” [16, 30]. This variant is estimated to increase the transmissibility of SARS-CoV-2 by 20% [31], thus explaining why, although identified in few samples in March 2020 (first Thai outbreak) before a strict lockdown measure was enforced, it had become the dominant strain by February 2021 (second Thai outbreak), similarly to what was observed in other South East Asian countries [32, 33]. The higher transmissibility of p.D614G can also explain the higher number of SARS-CoV-2 positive cases in the second compared to the first Thai outbreak.…”