Experimental dengue vaccine protects all recipients in virus challenge study

A clinical trial in which volunteers were infected with dengue virus six months after receiving either an experimental dengue vaccine or a placebo injection yielded starkly contrasting results. All 21 volunteers who received the vaccine, TV003, were protected from infection, while all 20 placebo recipients developed infection. The study underscores the importance of human challenge studies, in which volunteers are exposed to disease-causing pathogens under carefully controlled conditions.