Researchers in the United States have developed a method that could lead to a single vaccine against all four types of the dengue virus.
The dengue virus causes dengue hemorrhagic fever, shock and encephalitis. The four types of virus are all sufficiently different that individuals vaccinated against one virus type are still vulnerable to infection by the others.
There is currently no commercially available vaccine for protection against all types of dengue virus.
But John Dong of the Medical University of South Carolina, United States, and colleagues have developed a method that could lead to a safe and effective vaccine for all four types of the virus.
They produced a pair of synthetic vaccines, each containing genes from two of the four virus types. These successfully mimicked natural infection in mice, inducing an immune response against each of the four virus types at once.
The research was published in the February issue of the journal Clinical and Vaccine Immunology.
According to Dong, the synthetic vaccine demonstrated "100 per cent efficacy" in protecting the mice against all four dengue viruses. He added that the vaccine had also demonstrated safety in preclinical toxicology studies.
Dong told SciDev,Net that a further study on non-human primates has been conducted and will soon be submitted to a scientific journal for publication by colleagues at the US-based Naval Medical Research Center.
Prida Malasit of the Medical Biotechnology Unit in Bangkok, Thailand, welcomed the development. "There is no doubt on the importance of having the vaccine" he said.
He added that controlling dengue viruses was becoming a "formidable task for every country, not only for developing countries" because of rapidly expanding urbanisation and international travel.
Reference: Clinical and Vaccine Immunology 14, 182 (2007)