New York, Dec 8 (IANS): In a major step towards an effective human vaccine for Middle East Respiratory Syndrome (MERS) researchers have found that a two-for-one vaccine with a modified a rabies virus, so that it has a protein from the MERS virus, protects mice against both the diseases.

Because it uses an already-tested vaccine for rabies, the researchers believe that the innovative combination could speed development of a MERS vaccine for humans.

Currently no vaccine exists for this new and highly fatal virus.

"This is the first time anyone has used this strategy to create a MERS vaccine," said lead researcher Matthew Frieman, Associate Professor at University of Maryland School of Medicine in the US.

"This could give us a powerful mechanism to fight the virus," Frieman said.

MERS has killed more than 630 people since it was first discovered four years ago in Saudi Arabia. It has infected more than 1,800, meaning that about a third of those who are infected die -- a very high fatality rate for an infectious disease.

It appears that the disease spreads to humans from camels, who may themselves been infected by bats.

Through genetic engineering, Frieman and his colleagues produced a modified rabies virus that expresses a protein from the surface of the MERS virus, known as a spike protein, on the surface of the rabies virus.

Through an existing process, scientists then treated the modified virus chemically, inactivating it so that it cannot replicate.

This inactivated virus is itself the vaccine, which triggers an immune response but poses no danger to the recipient.

Because it included the MERS spike protein, the dual compound also triggered an immune response to MERS.

In tests on mice, the MERS-rabies vaccine protected against both diseases, showed the findings published in the Journal of Virology.

The researchers believe that the double vaccine could prove useful not only in humans, but also in camels, which are the reservoir of the MERS disease.