Immunogenicity and safety of tetravalent dengue vaccine in 2-11 year-olds previously vaccinated against yellow fever: Randomized, controlled, phase II study in Piura, Peru

► We gave YF-immunized children a 3-dose regimen of CYD tetravalent dengue vaccine. ► Reactogenicity was comparable to previous findings in flavivirus-naïve populations. ► After the 3rd dose 94% of children were seropositive to all 4 dengue serotypes. ► The CYD tetravalent dengue vaccine was safe and immunogenic in this population.