The emergence of Omicron VOC and its rapid spread and persistence in the Western Amazon

PLoS One. 2023 Aug 17;18(8):e0285742. doi: 10.1371/journal.pone.0285742. eCollection 2023.

Abstract

Genomic surveillance represents a strategy to understanding the evolutionary mechanisms, transmission, and infectivity of different SARS-CoV-2 variants. We evaluated 603 individuals positive for SARS-CoV-2 from 34 municipalities of Rondônia between December 2021 to December 2022. Nasopharyngeal samples were collected, RNA was extracted and screened using RT-qPCR for VOCs. RNA of the samples were sequenced and further analyzed for phylogeny, mutations, and lineages, totaling 96.19% of samples positive for Omicron VOC in this cohort. We observed that most individuals had at least two doses, however 18.97% were not vaccinated with any dose. 554 sequences were amenable to analysis for alignment and phylogenetic characterization; this group corresponded to the 27 subvariants of the Omicron VOC; a total of 100 mutations were identified, 48% of which were found in the S gene. In conclusion, the data demonstrated the rapid spread and persistence of Omicron VOC in Rondônia during the 12-month study period. Although high frequency of mutations was found in the analyzed samples, there were no individuals with a severe clinical profile, demonstrating that vaccination had a positive effect in those cases.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • COVID-19* / epidemiology
  • Humans
  • Phylogeny
  • RNA
  • SARS-CoV-2 / genetics

Substances

  • RNA

Supplementary concepts

  • SARS-CoV-2 variants

Grants and funding

This study was funded by Fundação Oswaldo Cruz de Rondônia – FIOCRUZ/RO, Departamento de Ciência e Tecnologia (DECIT), Fundação para o Desenvolvimento da Ação Científica e Tecnológica e à Pesquisa do Estado de Rondônia - FAPERO (Process:350.095.442.048.526.000.000/ 2016; Public bid invitation: 012/2016 PRO-RONDÔNIA and 001/2020 PPSUS) and by Instituto Nacional de Epidemiologia da Amazônia Ocidental - INCT EpiAmO. FGN is a CNPq fellow. Departamento de Ciência e Tecnologia (DECIT) of the Brazilian MoH, US/CDC and OPAS, Brazilian office. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.