Researchers have successfully tested a vaccine for the deadly Nipah virus in monkeys, raising hopes that it could provide similar protection for humans.

With greater than a 75 percent fatality rate and the ability to be transmitted directly from person to person, Nipah has long been a significant concern for infectious-disease experts. The virus, which is carried naturally by fruit bats, was first discovered in Malaysia in 1998. Outbreaks have occurred in nearly every year since, in Singapore, Bangladesh and India.

“This vaccine is based on a protein from Hendra virus, which is a very close relative of Nipah — Hendra’s found in Australia and is also spread by bats, which give it to horses, which give it to people,” said University of Texas Medical Branch at Galveston professor Thomas Geisbert, senior author of a paper on the study now online in Science Translational Medicine. “We’ve got a lot of confidence that the vaccine will work in people, because the animal model we used in this experiment, the African green monkey, faithfully reproduces all aspects of human Nipah and Hendra disease.”

Because there is no approved vaccine or therapy for Nipah, the researchers conducted their study in a biosafety level 4 “spacesuit” facility at the National Institutes of Health’s Rocky Mountain Laboratories in Hamilton, Mont. There, the scientists divided nine monkeys into three equal groups, administering a different vaccine dose to each group. 

Forty-two days later, the researchers infected the animals with what should have been a lethal dose of Nipah. But all of the vaccinated monkeys — even those that had received the lowest dose of the vaccine — remained completely healthy.

“The vaccine worked great,” Geisbert said.

The researchers plan further studies to prepare for a possible application for review by the Food and Drug Administration to license the vaccine for human use. In addition, the vaccine is now in commercial development in Australia to protect horses from Hendra virus.

Other authors of the Science Translational Medicine paper include Katharine Bossart and Andrew Hickey of Boston University; Barry Rockx and Joan Geisbert of UTMB; Friederike Feldmann, Doug Brining, Dana Scott, Rachel LaCasse and Heinz Feldmann of Rocky Mountain Laboratories; and Yan-Ru Feng, Yee-Peng Chan and Christopher Broder of the Uniformed Services University of the Health Sciences. Support for this research was provided by the National Institute of Allergy and Infectious Diseases and the NIH.