A US pharmaceutical firm is working on a vaccine for dengue fever with the potential to neutralise all four strains of the virus that cause the disease, its chief executive said Tuesday.
Clinical trials of the vaccine will begin in early 2009 in the United States with India and Southeast Asia slated to be the sites for further tests, said Dan Stinchcomb of Inviragen.
"We are focusing on trying to develop a dengue vaccine that can generate very good responses after just one or two doses and we think that this a key to success in this area," he said on the sidelines of the World Vaccine Congress Asia, an industry gathering.
"We plan to start on human testing next year but even then if all goes well, it won't be till 2013 or so that we can have a vaccine that can be marketed in Southeast Asia to help prevent the dengue epidemics that you speak about."
Dengue -- for which no vaccine is currently available -- is caused by four types of virus. Infection with any one of these viruses causes a mild fever and lifelong immunity to that strain.
In extreme cases dengue can be fatal.
The disease, transmitted mainly by the Aedes aegypti (yellow fever) mosquito, is endemic in Africa and the tropics. Infections have surged in recent years in Southeast Asian countries such as Singapore.
To completely eliminate dengue is nearly impossible, said Stinchcomb.
"Dengue is found almost everywhere.... It (Aedes mosquito) loves to live in the same sort of environments that people do and it is very adept at breeding in small amounts of water," he said.
"So it's been remarkably difficult to eradicate Aedes aegypti from tropical and subtropical regions throughout the world."
Around 50 million people become infected with dengue each year, of whom around 24,000 die. About 2.5 billion people worldwide are at risk of infection.
Scientists fear the virus may move into temperate regions as global warming opens up new habitats for the Aedes aegypti mosquito.