New York, Aug 4 (IANS): US researchers have devised an entirely new approach to vaccines - creating immunity against the dengue virus without vaccination.

The study demonstrated that animals injected with synthetic DNA engineered to encode a specific neutralising antibody against the dengue virus were capable of producing the exact antibodies necessary to protect against the disease, without the need for standard antigen-based vaccination.

Importantly, this approach, termed DMAb, was rapid, protecting animals within a week of administration, the study noted.

"We can produce a synthetic immune response by encoding an antibody and delivering it as a non-live, non-viral, non-permanent antibody," said senior study author David Weiner, professor at Perelman School of Medicine at the University of Pennsylvania in Philadelphia, US.

Dengue virus is one of the most important mosquito-borne viral infections in humans.

The geographical reach of dengue has expanded to include over 100 countries, resulting in a significant health and economic burden worldwide.

Although vaccines are being developed to fight dengue virus, none are currently available that provide balanced protection against all four dengue viral strains or serotypes.

Patients who are infected with one serotype develop protective immunity against that serotype alone - however, this immunity oddly leaves patients vulnerable to severe disease if future infections are caused by a different serotype.

In the current study, the DNA used to encode the neutralising antibodies against dengue virus was altered to produce a neutralising antibody that does not bind to cell receptors, effectively eliminating the chance for dengue infection to lead to enhanced, lethal disease.

The study was published in the journal Scientific Reports.