A vaccine is urgently needed to control dengue. There are at least five candidate vaccines in clinical trials and research. The World Health Organization (WHO) Strategic Advisory Group of experts on immunization recommended the first dengue vaccine, Dengvaxia, registered in Mexico in December 2015, only be used in geographic areas with a high endemicity. This vaccine is a tetravalent live recombinant vaccine given in three doses. It is only given to people age 9-45 years who live where dengue is endemic; therefore, younger patients and tourists are not eligible. The US National Institutes of Health (NIH) has started clinical trials on another live attenuated tetravalent vaccine that only requires one injection. It was reported effective in a small trial.