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

Takeda’s dengue vaccine is under evaluation in an ongoing phase 3 efficacy study. This article reports the two year update of the ongoing study. Children aged 4-16 years old (20 099) 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.

Cumulative efficacy against dengue approximately 27 months since first dose was 72.7%, including 67.0% in dengue-naive and 89.2% against hospitalized dengue. In the second year, decline in efficacy was observed (56.2%) with the largest decline in 4–5 year olds (24.5%); efficacy was 60.6% in 6–11 year and 71.2% 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.