New dengue vaccine proves 100 percent effective in trials
Aedes aegypti, the vector for the dengue and Zika viruses. Photo: James Gathany
18th March 2016
A DENGUE vaccine called TV003, currently undergoing clinical trials, could be the next best defense against the spread of the disease, and could potentially lead to a vaccine for the Zika virus as well, say researchers.
A recent study published in Science Translational Medicinerevealed that the vaccine had proven 100 percent effective against a modified version of Type 2 dengue after being tested on a small pool of human test subjects.
Normally, vaccines are tested using a large sample population within an area where the disease is common, which tends to be costly and time-consuming.
But for this study, researchers used a model called the “human challenge model”, which saw participants being injected with a weakened version of the dengue virus six months after receiving the vaccine .
In the U.S.-based experiment, 21 volunteers were given the TV003 vaccine, while another 20 volunteers were given a placebo as a control.
After being “infected” with the virus, none of the volunteers who received the vaccine showed any symptoms, while the control group developed rashes and the dengue virus could be detected in their blood.
TV003, which has been in development for the past 15 years, is said to be effective as it contains all four types of dengue, but with mutations that make them less potent.
Stephen Whitehead, a researcher at the National Institutes of Health in the U.S. who worked on the vaccine, told CNN: “Control of dengue has certainly been a public health priority for many years. But getting there has not been easy.”
“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,” he added.
A larger trial for the vaccine is currently being conducted in Brazil, where dengue is prevalent and a more recent Zika virus outbreak has been linked to birth defects, particularly microcephaly, where babies are born with abnormally small heads.
Associate professor in International Health at the Bloomberg School of Public Health at Johns Hopkins University, Anna Durbin, who was also the lead author in the study, said researchers hoped to replicate the process with the Zika virus, as both dengue and Zika share similarities in symptoms and are transmitted by the same species of mosquito.
“We hope to do this with Zika virus. There’s an urgent need for a Zika vaccine,” she said.
Another dengue vaccine, known as Dengvaxia, is also being tested in Mexico, Brazil, the Philippines and El Salvador, but has proven to be less effective against Type 2 dengue compared to Types 1, 3 and 4.
Dengue is endemic to Southeast Asian countries. The World Health Organization says more than 390 million infections are reported every year.
