Defeating dengue: a challenge for a vaccine

Dengue poses a substantial clinical problem, with the four serotypes of dengue viruses infecting 50-100 million people per year and approximately half the world's population estimated to be at risk. As there is no specific treatment for dengue, the development of an effective vaccine will be an important measure for controlling this disease. A phase 2b trial testing a recombinant live, attenuated tetravalent dengue-yellow fever chimeric virus vaccine in Thai schoolchildren of 4-11 years of age has recently been reported(1). The vaccine showed an overall efficacy of 30.2%, and one or more doses of the vaccine reduced the incidence of disease caused by the DENV3 and DENV4 dengue virus serotypes by 80-90%, with less reduction of disease caused by DENV1; however, there was no efficacy against DENV2. We asked three experts to comment on the results of this trial and how they might influence the landscape of dengue vaccine development.