In a small clinical trial led by the Johns Hopkins Bloomberg School of Public Health, researchers say that a promising single-dose dengue vaccine, developed by scientists at the National Institutes of Health, was 100 percent effective in preventing human volunteers from contracting the virus, the most prevalent mosquito-borne virus in the world.
The findings, published March 16 in Science Translational Medicine, could be the final puzzle piece in developing a vaccine that is effective against dengue, which infects nearly 400 million people across more than 120 countries each year. While most of those who are infected with dengue survive with few or no symptoms, more than two million people annually develop what can be a dangerous dengue hemorrhagic fever, which kills more than 25,000 people each year.
Preventing dengue has been a particular challenge. A three-dose vaccine called Dengvaxia received limited licensure in 2016 in Mexico, the Philippines, and Brazil. That vaccine produced antibodies against the dengue in a clinical trial and protected against dengue during the first year after vaccination. But two years after vaccination, children who were under the age of nine when they received the vaccine were hospitalized for dengue at a significantly higher rate than those who received the placebo. For this reason, the researchers, led by Dr. Anna P. Durbin, an associate professor in international health at the Bloomberg School, were concerned that measuring antibodies alone may not truly indicate the ability of the vaccine to protect against dengue.