1. In part 1, phase 3 of this randomized controlled trial, the overall vaccine efficacy of TAK-003 (dengue vaccine candidate) was approximately 80% among children ages 4 to 16 years old.
2. In addition, the vaccine increased the number of participants with seropositivity against dengue and showed to have significant efficacy against dengue leading to hospitalizations.
Evidence Rating Level: 1 (Excellent)
Study Rundown: Dengue fever is a mosquito-borne viral illness that causes nausea, vomiting, rash, eye, muscle, joint, and bone pain. It was designated as a top 10 threat to global health in 2019 by the World Health Organization. This study represents a phase of an ongoing randomized trial of a new tetravalent dengue vaccine candidate (TAK-003). Healthy children and adolescents were split into a vaccine group and placebo group. The vaccine group was given two doses over a 3-month period and then virologically tested for the efficacy of preventing dengue fever. The vaccine was more efficacious against dengue fever when compared to the placebo group (0.5 per 100 person-years vs. 2.5 per 100 person-years). In addition, the vaccine group had a lower rate of hospitalizations and was most efficacious against the DENV-2 serotype. This trial is ongoing but is an important step in determining the efficacy of the new TAK-003 vaccine candidate given the global health threat of dengue fever. Further trials are needed to determine long-term safety and efficacy of this vaccine.
In-Depth [randomized controlled trial]: This double-blind randomized controlled trial is part 1 of phase 3 of the TAK-003 dengue fever vaccine candidate. Part 1 aimed to protect against dengue fever for 12 months after the second vaccine dose. This study included 20,099 children ages 4 to 16 years old from 26 sites around Latin America and Asia. Participants received their first injection between September 2016 and March 2017 and received their second injection 3 months later. Blood specimens were obtained on day 1 before vaccination and day 120 to measure levels of dengue-neutralizing antibodies, and additional testing if the participant presented with a fever or clinically suspected dengue. The vaccine efficacy against all serotypes was 80.2% (95% CI, 73.3 to 85.3; P<0.001). The vaccine had a 97.7% efficacy against DENV-2, 73.7% against DENV01, 62.6% against DENV-3, and inconclusive for DENV-4. The vaccine efficacy against dengue leading to hospitalization was 95.4% (95% CI, 88.4 to 98.2). In addition, 99.5% of participants who were seronegative at baseline had seropositivity 1 month after the second dose of vaccine. Of note, adverse events were similar in the vaccine group and placebo group.
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