Early dengue vaccine test results are encouraging

An early test of a dengue vaccine did not yield ideal results, but scientists say that the study represents encouraging news in the battle against the disease.

Dengue currently has no available vaccine or treatment and can cause symptoms such as headache, fever, bleeding and severe joint pain. As many as 100 million people are infected by the mosquito-borne illness annually, primarily in Latin America, Africa and Asia, Associated Press reports.

"(The research) provides the first evidence we could actually develop an effective vaccine against dengue," Orin Levine, a professor at Johns Hopkins Bloomberg School of Public Health, said, according to Associated Press. "This is a milestone, but we're not there yet."

The vaccine given to more than 3,600 Thai children between the ages of four to 11. In the group that received three injections of the dengue vaccine, approximately three percent were infected with dengue. Approximately four percent of the group that did not receive the vaccine got the disease.

The vaccine appeared to be partly effective against three of the four viruses that cause dengue. There were no side effects reported.

The study occurred during an outbreak of mostly type 2 dengue, which the vaccine did not work against. Type 2 dengue typically causes the most serious disease.

Scott Halstead, a senior scientific advisor for the Dengue Vaccine Initiative, said scientists may need to consider creating separate shots for each type of dengue or reformulating the vaccine, according to Associated Press.