A single dose of TAK-003 elicited a high-to-very-high immunogenic response against all 4 serotypes, as well. Seroconversion rates exceeded 90% in children and adolescents and remained high at 70% or more in adults. The lowest seroconversion rates (70-80%) were observed against DENV-3 and DENV-4 in adult participants who were seronegative.
Due to a limited adult study population, all vaccine efficacy results based on intention-to-treat analyses referred to children and adolescents. After completing the 2-dose regimen, the vaccine significantly reduced the risk of dengue disease caused by DENV-2 and DENV-1 by over 80% and 40%, respectively, in both seropositive and seronegative individuals (P <.001).
However, vaccine effectiveness against DENV-3 and DENV-4 varied based on serological status. While the vaccine significantly protected those who were seropositive (RR = .50 for DENV-3; RR = 0.3 for DENV-4; both P <.001), it offered no protection for seronegative children and adolescents (P >.20).
Further, 1 or 2 doses of TAK-003 demonstrated excellent safety profiles, with a frequency of SAEs that was comparable with those observed among the controls.
Based on their findings, investigators offered suggestions for vaccination guidance.
“The vaccine was able to reduce the overall rate of dengue fever by more than half in both seronegative and seropositive children/adolescents,” they wrote.2 “Therefore, considering the results on safety, immunogenicity and efficacy following the administration of 2 vaccine doses, TAK-003 may certainly represent a central tool for the prevention of dengue fever among children and adolescents in highly endemic countries or within-country areas.”
Although 2 doses of TAK-003 are typically recommended for travelers from non-endemic regions visiting dengue-prone areas, researchers also suggested that a single vaccine dose could be considered for populations in non-endemic countries experiencing high dengue outbreaks.
This suggestion is especially important given the increasing global threat of dengue virus, whose incidence reached a record high in 2024.2 Climate change has exacerbated this surge by expanding the vector of dengue-carrying Aedes mosquitoes. The Americas have been particularly affected, with more than 9.7 million cases reported between January and June of this year alone—double the total amount of all cases reported in 2023.2
“Given the results in terms of safety, immunogenicity, and efficacy, the administration of 2 doses can undoubtedly be a key tool for dengue prevention,” said Maria Elena Flacco, lead study author and director of the school of specialization in public health at the University of Ferrara, in a news release.3 “The currently available vaccine can therefore be very useful not only for populations in endemic areas but also for travelers from non-risk areas.”
Going forward, investigators called for preferably independent studies to clarify the efficacy of TAK-003 for adults against serotypes 3 and 4 and the potential use of a single vaccine dose in non-endemic countries.
READ MORE: Immunization Resource Center
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References
1. Flacco ME, Bianconi A, et al. Immunogenicity, safety and efficacy of the dengue vaccine TAK-003: A meta-analysis. Vaccines. 2024; 12(7):770. https://doi.org/10.3390/vaccines12070770
3. The dengue vaccine is effective and safe: Confirmation from the first global meta-analysis. News release. EurekAlert. August 9, 2024. Accessed August 13, 2024. https://www.eurekalert.org/news-releases/1054168