There are four distinct but similar strains of dengue virus causing more than 100 million annual infections worldwide. Tropical regions are at especially high risk where illness may range from mild symptoms to potentially fatal forms of dengue hemorrhagic fever and dengue shock syndrome. With all four strains of the virus sharing similar clinical presentation, epidemiology, and distribution, development of a vaccine offering multi-faceted protection has become a global health priority.

In the study researchers developed a tetravalent dengue virus vaccine by combining genes and proteins from all four dengue virus types as well as incorporating an adenovirus agent. Following intramuscular vaccination, rhesus macaques showed high antibody levels that neutralized all four of the dengue virus types. To further test the sustainability of the protective immune response, two separate live-virus challenges were administered at 4 and 24 weeks after the final inoculation. Results showed complete protection against dengue types 1 and 3 and significant protection against types 2 and 4.

"Results reported here demonstrate that the tetravalent dengue vaccine elicited a neutralizing antibody response to all four dengue virus stereotypes and provided both short-term and long-term protection against challenges from each of the four serotypes," say the researchers.-American Society for Microbiology