Efficacy, public health impact and optimal use of the Takeda dengue vaccine

Dengue is the most common arboviral infection, causing substantial morbidity and mortality globally. The licensing of Qdenga, a second-generation vaccine developed by Takeda Pharmaceuticals, is therefore timely, but the potential public health impact of vaccination across transmission settings needs to be evaluated. To address this, we characterised Qdenga's efficacy profile using mathematical models calibrated to published clinical trial data and estimated the public health impact of routine vaccine use. We find that efficacy depends on the infecting serotype, serological status, and age. We estimate that vaccination of children aged over six years in moderate to high dengue transmission settings (seroprevalence at 9 years of age > 60%) could reduce the burden of hospitalised dengue by 10-22% on average over ten years. We find some evidence of a risk of vaccine-induced disease enhancement in seronegative vaccine recipients for dengue serotypes 3 and 4, especially for children under six years of age. Because of this, the benefits of vaccination in lower transmission settings are more uncertain, and more data on the long-term efficacy of Qdenga against serotypes 3 and 4 are needed.