Researchers at the University of Vermont (UVM) Vaccine Testing Center, along with collaborators at the National Institute of Allergy and Infectious Diseases (NIAID) at the National Institutes of Health and Johns Hopkins Bloomberg School of Public Health, have been working since 2008 to develop a dengue vaccine that will protect against all four dengue strains. The team's latest research, published today in Science Translational Medicine, reports promising results from clinical trials on a new vaccine that is very effective at preventing dengue infection and is likely to require only a single dose.
The World Health Organization has made the development and introduction of dengue vaccines a high priority. Approximately 40 percent of the world's population - 2.5 billion people - are at risk of contracting dengue, a viral infection spread by mosquitos in tropical and subtropical regions of the world. Dengue fever is best known for producing a high fever, rash and joint pain, but may also cause very serious disease, including hemorrhage and shock, as well as death. Development of vaccines for dengue has been complicated, since disease can be caused by any of four dengue virus serotypes and the vaccine must be tetravalent, providing equal protection against all four serotypes.
The NIH dengue vaccine was designed by Stephen Whitehead, Ph.D., a senior scientist and virologist at the Laboratory of Infectious Diseases at the NIAID. Clinical research was performed at both UVM and Johns Hopkins, where testing was led by Associate Professor Anna Durbin, M.D., corresponding author on the paper. Study volunteers were given vaccine or placebo and were tested for protection against a weakened strain of dengue that causes infection, but no or minimal symptoms. Results demonstrated that all vaccinees were protected from the "challenge" virus, but none of the volunteers receiving placebo vaccines were protected. The vaccine was well-tolerated in all volunteers.
"This work used a robust method which predicts a high likelihood of success for this critically important dengue vaccine," says UVM Professor of Medicine and Vaccine Testing Center Director Beth Kirkpatrick, M.D., who is first author on the paper. "I thank all members of the UVM, Johns Hopkins, and NIH dengue teams who have worked extremely hard over many years to develop this vaccine."
"The NIH dengue vaccine will now proceed to the ultimate test of effectiveness: large field-based trials in dengue-endemic countries," says Kristen Pierce, M.D., associate professor of medicine and UVM clinical investigator. "Beginning later this month, our team will be testing this vaccine in Dhaka, Bangladesh, and a large phase III efficacy trial has already begun in Brazil."