INTRODUCTION
viral disease, dengue, febrile, Dengue, VCD
VIRAL DISEASE, DENGUE, DENGUE
Dengue is a mosquito-borne viral disease that is endemic in more than 100 countries worldwide, predominantly in tropical and subtropical regions.The tetravalent, recombinant, live-attenuated dengue vaccine (TAK-003), which is based on a DENV serotype 2 (DENV-2) backbone, is currently being assessed in a large-scale, long-term, phase 3 efficacy trial in healthy children and adolescents living in dengue-endemic areas (NCT02747927).During the trial, vaccine efficacy was estimated using a Cox proportional hazards model, and only the first episodes of virologically confirmed dengue (VCD) were considered in the efficacy estimation. For serotype-specific efficacy, again only the first episodes caused by that specific serotype were considered. Because of the long duration of active febrile surveillance, we were able to document participants who experienced multiple VCD episodes from the first dose until 4.5 years after the two doses of trial vaccination. Herein, we describe these multiple episodes of symptomatic dengue, together with an exploratory estimate of the effect of vaccination on subsequent dengue episodes.