e-Risalah Jul-Sept 2024

The live-attenuated dengue tetravalent vaccine by the Japanese pharmaceutical company has shown long-term safety and efficacy for up to 4.5 years against symptomatic and hospitalised dengue cases, based on the TIDES study involving over 20,000 children and adolescents. The World Health Organization (WHO) recommends the programmatic use of Takeda’s dengue vaccine in children aged six to 16 years in settings with high dengue burden and transmission intensity for large-scale vaccination programmes. The vaccine should be administered in a two-dose schedule with a three-month interval between doses. Brazil became the first country to integrate the two-dose dengue vaccine into its public health care system, following a surge in dengue cases that alarmed health authorities. Rapid urbanisation, warmer temperatures, and heavier rainfalls create ideal conditions for the Aedes aegypti mosquito that spreads the dengue virus. In 2023, the Americas recorded the highest number of dengue cases ever, with 4,617,101 cases and 2,423 deaths, according to the Pan American Health Organization (PAHO). Brazil alone accounted for over three million cases. The latest PAHO figures for 2024 show that dengue cases in the Americas have far outpaced last year’s record, reaching 8,991,508 cases and 4,157 deaths, with Brazil recording more than 7.5 million cases. With Brazil facing its worst dengue outbreak, new interventions and advancements in vector control and dengue vaccines are crucial for managing the expanding threat, said infectious disease physician and adjunct associate professor of epidemiology at the Yale School of Public Health, Prof Dr Julio Croda. The vaccine received registration approval from Brazil’s national drug regulator Anvisa in March 2023, allowing it to be marketed in Brazil under approved conditions. In December 2023, Brazil’s Ministry of Health announced the vaccine’s incorporation into the public health care network. The doses began distribution in January this year to 521 municipalities selected by the health ministry to initiate vaccination within the Brazilian public health system. These municipalities represent only 9 percent of the 5,570 municipalities in Brazil. The selected cities will vaccinate children and adolescents aged 10 to 14, a demographic with the second- highest number of dengue-related hospitalisations, second only to the elderly. The municipality of Dourados, located in the state of Mato Grosso do Sul, was the first city in Brazil to launch a mass dengue vaccination campaign, targeting to vaccinate 120,000 individuals aged between four and 60. Dourados experienced a high incidence of dengue in 2023, with 1,388 cases per 100,000 inhabitants or a total of 3,378 cases in a population of 243,368. “Children aged under 10 to 14 still have one of the lowest vaccination coverage in general,” Dr Croda said, in summarising the lessons learned from Brazil’s dengue vaccination campaign to date. He attributed the low uptake of the dengue vaccine among this group to limited awareness of dengue mortality and morbidity, and highlighted the necessity of an effective communication campaign to complement vaccination efforts. CampusNews 31