Investigação da história evolutiva da variante de preocupação Gama de SARS-CoV-2 no estado do Ceará

Abstract

Since the emergence of the new coronavirus (SARS-CoV-2) in Wuhan in December 2019 until now, much has been uncovered and documented, including its evolutionary process. However, the lack of epidemiological studies of laboratory surveillance in several regions of Brazil, such as the state of Ceara, represents a knowledge gap yet to be filled. Prospective regionalized investigations of Variants of Concern (VOCs) allow a better understanding of the viral dynamics and dissemination, enabling the design of targeted strategies for tackling the etiological agent. This study aims to present hypotheses and prospects on the introduction, expansion and decline of the VOC Gamma (P.1 lineage) of SARS-CoV-2 in the state of Ceará during the period of December 2020 to November 2021. For this purpose, the methodology employed made use of temporal maximum-likelihood Estimation and Bayesian inference to determine the probable period of introduction of the variant, as well as its reproductive number, geographical dispersions, along with the use of in-house algorithms to assess the variation of the virus mutation profile over time. Different datasets were created using genomes from the international reference database GISAID and data made available by the Laboratory of Molecular Biology and Diagnostic Innovation (BIOMIND) at the Hematology and Hemotherapy Center of Ceara. The analyses indicate that the first introduction of VOC Gamma in Ceará occurred most likely in December 2020, with subsequent introductions coming particularly from North and Northeast great regions of the country. Furthermore, it was inferred that the State’s capital, Fortaleza, was the epicenter for the introduction and spread of P.1-like lineages to the other municipalities of the state. Lastly, this work suggests that: i) it has probably occurred a delay in identifying the first VOC Gamma in the state; ii) the likely key direction of dissemination and spread was from the capital to the countryside; and iii) various concomitant introductions subsequently took place coming from various regions of the country. In summary, this work reinforces the relevance of the implementation of molecular surveillance strategies of emerging viruses and the continuous monitoring of their lineages and variants for the tailoring preventive and containment measures.