Microorganisms (Aug 2024)

Retrospective Analysis of Omicron in Minas Gerais, Brazil: Emergence, Dissemination, and Diversification

  • Paula Luize Camargos Fonseca,
  • Isabela Braga-Paz,
  • Luiza Campos Guerra de Araújo e Santos,
  • Rillery Calixto Dias,
  • Carolina Senra Alves de Souza,
  • Nara Oliveira Carvalho,
  • Daniel Costa Queiroz,
  • Hugo José Alves,
  • João Locke Ferreira de Araújo,
  • Filipe Romero Rebello Moreira,
  • Mariane Talon Menezes,
  • Diego Menezes,
  • Aryel Beatriz Paz e Silva,
  • Jorge Gomes Goulart Ferreira,
  • Talita Emile Ribeiro Adelino,
  • André Felipe Leal Bernardes,
  • Natália Virtude Carobin,
  • Renée Silva Carvalho,
  • Carolina Zaniboni Ferrari,
  • Natália Rocha Guimarães,
  • Ludmila Oliveira Lamounier,
  • Fernanda Gil Souza,
  • Luisa Aimeé Vargas,
  • Marisa de Oliveira Ribeiro,
  • Monica Barcellos Arruda,
  • Patricia Alvarez,
  • Rennan Garcias Moreira,
  • Eneida Santos de Oliveira,
  • Adriano de Paula Sabino,
  • Jaqueline Silva de Oliveira,
  • José Nélio Januário,
  • Felipe Campos de Melo Iani,
  • Renan Pedra de Souza,
  • Renato Santana Aguiar

DOI
https://doi.org/10.3390/microorganisms12091745
Journal volume & issue
Vol. 12, no. 9
p. 1745

Abstract

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Brazil is one of the countries most affected by COVID-19, with the highest number of deaths recorded. Brazilian Health Institutions have reported four main peaks of positive COVID-19 cases. The last two waves were characterized by the emergence of the VOC Omicron and its sublineages. This study aimed to conduct a retrospective surveillance study illustrating the emergence, dissemination, and diversification of the VOC Omicron in 15 regional health units (RHUs) in MG, the second most populous state in Brazil, by combining epidemiological and genomic data. A total of 5643 confirmed positive COVID-19 samples were genotyped using the panels TaqMan SARS-CoV-2 Mutation and 4Plex SC2/VOC Bio-Manguinhos to define mutations classifying the BA.1, BA.2, BA.4, and BA.5 sublineages. While sublineages BA.1 and BA.2 were more prevalent during the third wave, BA.4 and BA.5 dominated the fourth wave in the state. Epidemiological and viral genome data suggest that age and vaccination with booster doses were the main factors related to clinical outcomes, reducing the number of deaths, irrespective of the Omicron sublineages. Complete genome sequencing of 253 positive samples confirmed the circulation of the BA.1, BA.2, BA.4, and BA.5 subvariants, and phylogenomic analysis demonstrated that the VOC Omicron was introduced through multiple international events, followed by transmission within the state of MG. In addition to the four subvariants, other lineages have been identified at low frequency, including BQ.1.1 and XAG. This integrative study reinforces that the evolution of Omicron sublineages was the most significant factor driving the highest peaks of positive COVID-19 cases without an increase in more severe cases, prevented by vaccination boosters.

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