A new type of vaccine, the first developed to combat dengue fever, has been able to protect individuals against three of the four current viral strains.
Dengue fever, also known as breakbone fever, is an infectious tropical disease caused by the dengue virus, which is transmitted through several types of mosquito. The symptoms include fever, a rash, headache, muscle and joint pains. This later develops into dengue hemorrhagic fever, a life-threatening condition that results in bleeding, blood plasma leakage, and shock when blood pressure drops to dangerous levels.
The only ways to treat the disease are oral or intravenous rehydration and blood transfusion. However, the new vaccine — developed by French drugmaker Sanofi SA — has shown positive results in a Thai clinical trial.
Sanofi’s vaccine generated an antibody response for all four dengue virus types, but only protected against three of the four, which are all in circulation around Thailand. The company’s researchers are currently completing additional studies to try and discover why it was not as successful in the third strain.
“It’s a surprise,” company spokesman Pascal Barollier told the publication.
“We need to get to the bottom of the data to find out why it is reacting this way and wait for ongoing Phase III trials to see if it is linked to some specific situation in Thailand.”
The Phase II study involved over 4000 Thai children aged between four and eleven years old. It was conducted during an epidemic of the disease, which may be linked to why the fourth strain’s protection was not as successful.
Other companies are also working on a viable dengue shot, but the French drugmaker’s is several years ahead in development and trial status. As there is a current lack of protection against the fourth strain, a commercial launch is likely to be delayed from an expected 2014 release. Instead, it is likely to be launched in 2015, after Phase III trial data has been collected.
Most patents survive contracting the disease, but according to World Health Organisation estimates, it still kills 20,000 people per year — and most fatalities are children.
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