Efficacy of a Dengue Vaccine Candidate (TAK-003) in Healthy Children and Adolescents 2 Years after Vaccination

• Main Authors: Eduardo López-Medina, Shibadas Biswal, Xavier Saez-Llorens, Charissa Borja-Tabora, Lulu Bravo, Chukiat Sirivichayakul, Luis Martinez Vargas, Maria Theresa Alera, Hector Velásquez, Humberto Reynales, Luis Rivera, Veerachai Watanaveeradej, Edith Johana Rodriguez-Arenales, Delia Yu, Felix Espinoza, Reynaldo Dietze, Lak Kumar Fernando, Pujitha Wickramasinghe, Edson Duarte Moreira, Asvini D. Fernando, Dulanie Gunasekera, Kleber Luz, Rivaldo Venâncio Da Cunha, Vianney Tricou, Martina Rauscher, Mengya Liu, Inge Lefevre, Derek Wallace, Pope Kosalaraksa, Astrid Borkowski
• Other Authors: Faculty of Tropical Medicine, Mahidol University
• Format: Article
• Published: 2022
• Subjects: Medicine
• Online Access: https://repository.li.mahidol.ac.th/handle/123456789/74603
• Institution: Mahidol University

Background: Takeda's dengue vaccine is under evaluation in an ongoing phase 3 efficacy study; we present a 2-year update. Methods: Children (20 099, 4-16 years old) were randomized to receive 2 doses of TAK-003 or placebo 3 months apart and are under surveillance to detect dengue by serotype-specific RT-PCR. Results: Cumulative efficacy against dengue approximately 27 months since first dose was 72.7% (95% confidence interval [CI], 67.1%-77.3%), including 67.0% (95% CI, 53.6%-76.5%) in dengue-naive and 89.2% (95% CI, 82.4%-93.3%) against hospitalized dengue. In the second year, decline in efficacy was observed (56.2%; 95% CI, 42.3%-66.8%) with the largest decline in 4-5 year olds (24.5%; 95% CI, -34.2% to 57.5%); efficacy was 60.6% (95% CI, 43.8%-72.4%) in 6-11 year and 71.2% (95% CI, 41.0%-85.9%) in 12-16 year age groups. As TAK-003 efficacy varies by serotype, changes in serotype dominance partially contributed to efficacy differences in year-by-year analysis. No related serious adverse events occurred during the second year. Conclusions: TAK-003 demonstrated continued benefit independent of baseline serostatus in reducing dengue with some decline in efficacy during the second year. Three-year data will be important to see if efficacy stabilizes or declines further.