Ebola Vaccine Found, Experiment on Animals in Guinea Succesful,Clinical Trials on Human Undergoing

 A single dose of an experimental Ebola virus (EBOV) vaccine, currently undergoing testing in humans, completely protects animals against the current outbreak strain, when given at least seven days before exposure, scientists have found.

The vaccine partially protects the cynomolgus macaques against the EBOV-Makona strain if given three days prior, researchers said.

The live-attenuated vaccine, VSV-EBOV, uses genetically engineered vesicular stomatitis virus (VSV) to carry an EBOV gene that has safely induced protective immunity in macaques.

The experimental vaccine is currently undergoing testing in a global clinical trial in humans.

VSV, an animal virus that primarily affects cattle, has been successfully tested as an experimental vaccine platform against several viruses.

Prior to this study, scientists had no information about how animals vaccinated with VSV-EBOV would respond to a challenge with EBOV-Makona, which has spread throughout West Africa.

Previous animal studies demonstrated that VSV-EBOV could successfully protect monkeys against the first EBOV strain recognised, Mayinga, in 1976, and against EBOV-Kikwit, a strain that emerged in Central Africa in 1995.

As per US News,Dr. Margaret Chan, director general of the World Health Organization, said in a call with reporters Friday  "If proven effective, this is going to be a game-changer," . "It will change the management of the current Ebola outbreak and future outbreaks." 

Assistant Director-General Marie-Paule Kieny, who leads the Ebola Research and Development effort at WHO, said in a statement that the work marked a turning point in the history of research and development. "We now know that the urgency of saving lives can accelerate R and D," she said as reported by US News. 

"We will harness this positive experience to develop a global R and D preparedness framework so that if another major disease outbreak ever happens again, for any disease, the world can act quickly and efficiently to develop and use medical tools and prevent a large-scale tragedy." She added

This new study shows that certain immune responses induced by VSV-EBOV are similar against all three viruses.

The various scientists, from US National Institutes of Health (NIH)'s National Institute of Allergy and Infectious Diseases Division of Intramural Research, concluded from these findings that VSV-EBOV likely would be equally protective against different EBOV strains.

They have also observed that the experimental VSV-EBOV vaccine may provide initial protection by triggering innate virus-fighting host responses; these responses partially protected animals challenged with EBOV-Makona within a week after vaccination.

Animals vaccinated more than a week before viral challenge developed antibodies, an adaptive immune response, that were shown to be critical for protection, researchers said.

The testing method in Guinea was similar to that of smallpox, called a "ring" vaccination method. It works by vaccinating people who have come into contact with an infected person, by creating a protective "ring" and stopping the virus from spreading. Until now, half of the rings were vaccinated three weeks after someone with Ebola had been identified, and were compared with rings vaccinated immediately. Ebola symptoms – which include fever, diarrhea and vomiting – can begin three weeks after coming into direct contact with someone who is infected. 

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News Source- PTI &USNEWS.COM

Image source-WHO source (for representation purpose only)