Ebola Virus Vaccine Proves Effective on Chimpanzees

Ebola hemorrhagic fever is a severe and contagious disease that is contracted by humans as well as primates, such as monkeys, gorillas, and chimpanzees (among other animals). Its recent outbreak in West Africa has killed over 170 people.         

Researchers from the University of Cambridge as well as many from the United States conducted the first conservation-specific Ebola vaccine trial on captive chimpanzees. They found that the vaccine is safe and capable of producing a robust immune response in the chimps, and they hope to soon license it for human use.

The researchers believe that this "orphan" vaccine - one that is used to treat rare infectious diseases or those of narrow scope - could be effective in preserving wild ape populations. Ebola outbreaks in Africa wiped out nearly one-third of the world gorilla population by 2007. The virus is more deadly among animals, but this vaccine could potentially be used to treat humans who are also threatened by Ebola throughout the African continent.

"Half of deaths among chimps and gorillas that live in proximity to humans are from our respiratory viruses. For us it's a sore throat - for them it's death," said Peter Walsh of Cambridge University and senior author of the study, in a news release. "There is a large pool of experimental vaccines that show excellent safety and immunity profiles in primate trails but are never licensed for human use."

Using a new "virus-like particle" vaccine developed by Integrated Biotherapeutics and intended for human use, the researchers treated captive chimpanzees and found that the chimps developed robust immune responses with virus-specific antibodies. Multiple administrations of the vaccine are required for full potency and it is completely safe for animal use. Although none of the chimpanzees were infected with the Ebola virus, the researchers got the results they hoped for.

As a result of the vaccine's success, the authors suggest that the U.S. Fish and Wildlife Service establish a "humanely housed" captive chimpanzee population dedicated to conservation research, similar to this study, in order to preserve key species. The success in the first-ever study of this kind could persuade the U.S. to do so.

The researchers from Cambridge, the New Iberia Research Centre, the U.S. Army, the University of Louisiana, and Apes Incorporated had their results published in the Proceedings of the National Academy of Sciences.