James Siqueira Pereira, Isabela Carvalho Brcko, Gabriel Montenegro de Campos, Vinicius Carius de Souza, Igor Santana Ribeiro, Mariana Matos Rolle, Brenno Vinicius Martins Henrique, Felicidade Mota Pereira, Arabela Leal E Silva de Mello, Aline de Andrade Freund, Juan Gabriel Carvalho de Araújo, Talita Émile Ribeiro Adelino, Marta Lamounier Moura Vargas Corgozinho, Valnete das Graças Dantas Andrade, Gleissy Adriane Lima Borges, Stephanni Figueiredo da Silva, Elaine Cristina de Oliveira, Glaucilene da Silva Costa, Cicileia Correia da Silva, Mariana de Souza Araujo, Melissa Palmieri, Luiz Carlos Junior Alcantara, Claudia Renata Dos Santos Barros, Tiago Souza Salles, Svetoslav Nanev Slavov, Sandra Coccuzzo Sampaio, Maria Carolina Elias, Marta Giovanetti, Alex Ranieri Jeronimo Lima
Brazil is the most hyperendemic country for dengue, with historically dominant circulation of DENV-1 and DENV-2. Bayesian phylodynamic analyses of 489 Brazilian DENV-3 genomes, including 84 newly generated sequences, reveal a recent and sustained increase in the effective population size of DENV-3 associated with the recent introduction and expansion of the 3III_B.3.2 lineage. This increase coincides with a sharp rise in the proportion of laboratory-confirmed dengue cases attributed to DENV-3 among records with available serotype information from 2024 onwards and a shift in serotype dynamics in 2025, suggesting a change in serotype distribution and a potential risk of renewed DENV-3 outbreaks, particularly in populations with limited prior exposure to this serotype.