Volume 32, Number 4—April 2026
Research
Dengue Incidence, Seroprevalence, and Expansion Factors from Active Surveillance, Brazil, 2016–2021
Figure 1

Figure 1. VCD and laboratory-confirmed chikungunya incidence by demographic characteristics, Brazil, 2016–2021. Incidence per 100 person-years of VCD is shown regardless of serotype (A), VCD by DENV serotypes DENV-1 and DENV-2 (B), and laboratory-confirmed chikungunya (C) among participants in the placebo arm of the DEN-03-IB trial of a live attenuated tetravalent dengue vaccine, Butantan-DV, by demographic characteristic (age at event, sex, and baseline dengue serostatus). Points represent incidence estimates and error bars represent 95% CIs. Dashed lines represent the overall incidence per 100 person-years and shaded areas around the dashed lines represent 95% CIs for the overall incidence estimates. Prior exposure (i.e., dengue seropositive) is defined as having a baseline 60% virus reduction neutralization test titer to any of the 4 DENV serotypes above the assay limit of detection. +, positive; –, negative; DENV, dengue virus; VCD, virologically confirmed dengue.
1Preliminary results from this study were presented at the American Society for Tropical Medicine and Hygiene annual meeting; November 13–17, 2024; New Orleans, Louisiana, USA.