Retrospective epidemiologic and genomic surveillance of arboviruses in 2023 in Brazil reveals high co-circulation of chikungunya and dengue viruses.

Background: The rapid spread and increase of chikungunya (CHIKV) and dengue (DENV) cases in Brazilian regions in 2023 has raised concerns about the impact of arboviruses on public health. Epidemiological and genomic surveillance was performed to estimate the introduction and spread of CHIKV and DENV in Brazil.

Methods: This study obtained results from the Hermes Pardini (HP), a private medical laboratory, and the Health Department of Minas Gerais state (SES-MG).

Epidemiological Surveillance Reveals the Rise and Establishment of the Omicron SARS-CoV-2 Variant in Brazil.

The introduction of SARS-CoV-2 variants of concern (VOCs) in Brazil has been associated with major impacts on the epidemiological and public health scenario. In this study, 291,571 samples were investigated for SARS-CoV-2 variants from August 2021 to March 2022 (the highest peak of positive cases) in four geographical regions of Brazil. To identify the frequency, introduction, and dispersion of SARS-CoV-2 variants in 12 Brazilian capitals, VOCs defining spike mutations were identified in 35,735 samples through genotyping and viral genome sequencing.

The Omicron Lineages BA.1 and BA.2 ( SARS-CoV-2) Have Repeatedly Entered Brazil through a Single Dispersal Hub.

Brazil currently ranks second in absolute deaths by COVID-19, even though most of its population has completed the vaccination protocol. With the introduction of Omicron in late 2021, the number of COVID-19 cases soared once again in the country. We investigated in this work how lineages BA.