WHO releases final trial results for promising Ebola vaccine

According to a recently published study, an experimental Ebola virus vaccine, called rVSV-ZEBOV, was highly protective against the deadly virus in a major trial that took place in Guinea.

The study was conducted by the World Health Organization (WHO), along with Guinea’s Ministry of Health, Medecins sans Frontieres and the Norwegian Institute of Public Health.

This vaccine is the first of its kind to prevent infection from the deadly Ebola pathogen, building upon findings from trial results published in 2015. The vaccine was manufactured by Merck, Sharpe & Dohme and received breakthrough therapy designation from the U.S. Food and Drug Administration. It also received PRIME status from the European Medicines Agency, which enables faster regulatory review of the vaccine once it is submitted.

“Ebola left a devastating legacy in our country. We are proud that we have been able to contribute to developing a vaccine that will prevent other nations from enduring what we endured,” KeÏta Sakoba, coordinator of the Ebola Response and director of the National Agency for Health Security in Guinea, said.

The trial involved 11,841 people in Guinea in 2015. Among the 5837 participants who received the vaccine, no Ebola cases were reported 10 days or more after vaccination. Among remaining participants who did not receive the vaccine, 23 cases of Ebola infection were reported 10 days or more after exposure.

To assess the vaccine’s safety and efficacy, subjects were observed 30 minutes after vaccination, followed by home visits approximately 12 weeks later. Half of the vaccinated subjects reported mild symptoms with two subjects reporting more severe symptoms. All subjects, however, recovered shortly after symptoms were first reported. The vaccine is still being tested on its safety for children.

“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,” Marie-Paule Kieny, assistant director-general for health systems and innovation at WHO, said.