GENEVA, Switzerland, Dec. 24 (UPI) — An experimental Ebola vaccine proved to be 100 percent effective in eradicating the deadly disease when used in a major clinical trial in Guinea, researcher said Friday.

The vaccine, not yet approved by regulatory authorities, is the first created to stop the deadly pathogen. An emergency stockpile of 300,000 doses have been created to fend off a flare up of the virus. The vaccine was studied with 11,841 people in Guinea during 2015. Of the 5,837 people who received the vaccine, no Ebola cases were recorded 10 days or more after vaccination.

“While these compelling results come too late for those who lost their lives during West Africa’s Ebola epidemic, they show that when the next Ebola outbreak hits, we will not be defenseless,” said Dr Marie-Paule Kieny, the World Health Organization’s assistant director-general for health systems and innovation, and the study’s lead author.

Since Ebola was first identified in 1976, thousands of people have died, including more than 11,300 people from 2013 to 2016.

The vaccine, developed by the Public Health Agency of Canada and manufactured by Pharma giant Merck & Co., uses an animal virus that is harmless to people. For the research, scientists used the “ring vaccination” approach, similar to what was used to eradicate small pox. Research teams tracked down everyone who may have been in contact with a case, including family and friends. A total of 117 “rings” of people were identified, each with about 80 people. Of those, half were vaccinated and half not.

“After interim results were published showing the vaccine’s efficacy, all rings were offered the vaccine immediately and the trial was also opened to children older than 6 years,” WHO officials said. “In addition to showing high efficacy among those vaccinated, the trial also shows that unvaccinated people in the rings were indirectly protected from Ebola virus through the ring vaccination approach (so called ‘herd immunity’).” Additional research is needed.