In December 2023, the tetravalent dengue vaccine produced by Takeda Pharmaceuticals (TAK-003) was introduced into the Brazilian vaccination schedule, supplied by the Unified Health System (SUS) to individuals aged 10 to 14 years from February 2024 onward. The efficacy and safety of this vaccine had been previously demonstrated, and clinical trials had not reported cases of anaphylaxis. However, during large-scale implementation in Brazil, a significant number of cases were reported as anaphylaxis or hypersensitivity reactions (incidence of 63.1 cases of anaphylaxis or anaphylactic shock per 1 million doses administered). In Belo Horizonte, an incidence of anaphylaxis and hypersensitivity reactions higher than the national rate was observed. Descriptive study of events characterized as anaphylaxis or hypersensitivity recorded in the municipality of Belo Horizonte, Minas Gerais, between February 2024 and February 2025, extracted from the e-SUS Notifica system, with vaccination data complemented from SI-PNI. A total of 146,115 doses of the vaccine were administered to children aged 6 to 14 years, with 104,286 first doses and 41,829 second doses, all administered in primary care. In the same period, 28 adverse events after vaccination were reported, classified as anaphylaxis or hypersensitivity reaction, resulting in an incidence of 191.6 cases per 1 million doses administered. However, all cases were attributed to the first dose of the vaccine, corresponding to 268.4 cases per 1 million first doses administered. The events were associated with eight different vaccine batches. None of the cases had a record of concomitant administration of other vaccines, and only two patients had a history of previous allergies. The mean time to onset of signs and symptoms was 31.2 minutes, and 27 (96.4%) individuals received medical care, with 26 of them receiving some medication. Only three cases (10.7%) required adrenaline prescription, and all patients had complete recovery and were discharged after less than 24 hours of observation in a health unit. An incidence above the expected rate of adverse events not described in clinical trials of the TAK-003 vaccine was observed, which is particularly relevant considering that the analyzed group has a lower risk of developing severe dengue-related outcomes.
Junior et al. (Sun,) studied this question.