Effect of the Tetravalent Dengue Vaccine TAK-003 on Sequential Episodes of Symptomatic Dengue

In the pivotal phase 3 efficacy trial (NCT02747927) of the TAK-003 dengue vaccine, 5 of 13,380 TAK-003 recipients and 13 of 6,687 placebo recipients experienced two episodes of symptomatic dengue between the first dose and the end of the study, ∼57 months later (patients received the second dose 3 months after the first dose). Two of these participants experienced repeat infection with the same serotype (i.e., homotypic reinfection). In comparison with placebo, the relative risk of a subsequent episode of symptomatic dengue was 0.19 (95% CI, 0.07–0.54) in TAK-003 recipients. Based on the small number of subsequent episodes, these data suggest a potential incremental effect of TAK-003 beyond prevention of the first episode of symptomatic dengue after vaccination.