Baseline Anti-Dengue IgG Seroprevalence in a Pediatric Brazilian Population Before TAK-003 Vaccination

Dengue remains a major public health challenge in Brazil, with recurrent outbreaks placing a strain on healthcare systems. The TAK-003 vaccine offers a promising control strategy, particularly for children. This cross-sectional study evaluated the seroprevalence of anti-dengue IgG in 643 children and adolescents aged 4-16 years in Dourados, Brazil, before being administered the TAK-003 vaccine. Capillary blood samples were collected on filter paper and analyzed using ELISA; sociodemographic data were obtained through questionnaires. Overall, 20.5% of participants were seropositive. Seropositivity increased with age, with 27.7% among those aged 13-16 years testing positive compared with 13.4% among children aged 4-8 years. Male sex was associated with lower IgG levels. The age-related increase in anti-dengue IgG seroprevalence reflects cumulative exposure to the virus during childhood and adolescence, highlighting the need for immunization strategies tailored to age. These findings emphasize the importance of baseline anti-dengue IgG seroprevalence data to guide vaccination, assess effectiveness, and monitor antibody-dependent enhancement risks.