Estudo epidemiológico e molecular da variante Omicron do SARS-CoV-2 no Estado do Tocantins

• Ano de defesa: 2024
• Autor(a) principal: Santos, Mateus Silva
• Orientador(a): Soares, Celia Maria de Almeida
• Banca de defesa: Soares, Celia Maria de Almeida, Bailão, Alexandre Melo, Souza, Menira Borges de Lima dias e, Oliveira, Lucas Nojosa, D’Alessandro​, Walmirton Bezerra
• Tipo de documento: Tese
• Tipo de acesso: Acesso aberto
• Idioma: por
• Instituição de defesa: Universidade Federal de Goiás
• Programa de Pós-Graduação: Programa de Pós-graduação em Medicina Tropical e Saúde Publica (IPTSP)
• Departamento: Instituto de Patologia Tropical e Saúde Pública - IPTSP (RMG)
• País: Brasil
• Palavras-chave em Português: COVID-19; SARS-CoV-2; Omicron
• Palavras-chave em Inglês: SAR-CoV-2
• Área do conhecimento CNPq: CIENCIAS BIOLOGICAS::MICROBIOLOGIA
• Link de acesso: http://repositorio.bc.ufg.br/tede/handle/tede/13514

Introduction: SARS-CoV-2 infection associated with COVID-19 is one of the greatest global public health challenges, contributing to high morbidity and mortality in different age groups, with some population segments being more affected. The emergence of new variants of the SARS-CoV-2 virus, such as Omicron, is a reflection of selective advantage, translated as greater transmissibility and the ability to replicate in people previously exposed to the virus. In Brazil, the variant was very prominent, even when the numbers of immunized individuals were already high. Therefore, this research aims to promote an epidemiological and molecular study on the Omicron variant of SARS-CoV-2 in the state of Tocantins. Methods: This is an analytical cross-sectional study with a quantitative approach, conducted using SARS-CoV-2 positive samples from the Central Laboratory of Public Health of Tocantins (LACEN-TO). The samples were sequenced and taken to experiments in order to verify the quality of the sequencing, detect possible mutations and identify the main variants of concern. Subsequently, phylogenetic analysis was performed in order to observe the degree of dispersion of the most predominant variant in the state of Tocantins. Results: In the present study, 556 samples positive for the Omicron variant of SARS-CoV-2 were used. Among the results, it was observed that the state of Tocantins presented, during the study period, about 39 lineages of the Omicron variant, some of which were associated with a higher transmissibility rate. The biggest highlight was the XBB.1.18.1 and XBB.1.5 subvariants, being one of the main circulating in Tocantins in 2023. Phylogenetic analyses suggest that the state may have contributed to the dispersion of the subvariants not only in Brazil but also in the world. Conclusions: The results of the present study showed a high prevalence of the Omicron variant in Tocantins between December 2021 and June 2023, in addition to showing that the state may have contributed to the spread of the XBB.1.18.1 subvariant in Brazil. Relevance and impact: It is worth noting that due to the high frequency of mutations of the Omicron variant of SARS-CoV-2, surveillance is necessary to identify possible new entries of the virus not only in the northern Brazilian state but also throughout the country.