All of the subjects who participated in a clinical trial for an experimental dengue virus vaccine showed vastly different results, as the 21 vaccine recipients did not develop the dengue infection, but the 20 placebo recipients did contract the infection.
Dengue fever typically occurs in the subtropics and tropics. People develop this disease after being bitten by Aedes mosquitoes that are infected with the dengue virus.
The team of researchers from the National Institutes of Health (NIH) gave the subjects either the experimental dengue vaccine or a placebo injection. They were surprised that the study results, available in Science Translational Medicine, were so obvious.
The scientists state that this study is a testimony to how crucial these human challenge studies are for modern medicine. In these kinds of studies, the volunteers have exposure to pathogens only within strictly controlled conditions.
“The findings from this trial are very encouraging to those of us who have spent many years working on vaccine candidates to protect against dengue, a disease that is a significant burden in much of the world and is now endemic in Puerto Rico,” Dr. Stephen Whitehead, of NIH’s National Institute of Allergy and Infectious Diseases (NIAID), said. “In fact, these results informed the recent decision by officials at Brazil’s Butantan Institute to advance the TV003 vaccine into a large phase 3 efficacy trial.”