World Health Organization (WHO) has expressed confidence that a prototype vaccine for Ebola may be 100% effective in protecting against the deadly virus Ebola. The vaccine was initially developed in Canada by public health authorities before being taken over by pharmaceutical giant Merck. Earlier in a major human clinical trial conducted of this vaccine on nearly 6,000 people in Guinea in 2015 was found to successfully as it was observed that not one of the 6,000 contracted the disease. It said the vaccine could become available in 2018 under a fast-track approval process. Â Ebola virus was first identified in 1976 in the Democratic Republic of Congo. Fruit bats are natural host of this virus. In early 2014, it had erupted periodically mainly across west and east Africa mainly in Guinea, Liberia and Sierra Leone. It causes violent and painful symptoms, including vomiting, diarrhoea, organ failure and internal bleeding. It has mortality rate above 40%.