An experimental Ebola vaccine was highly effective against the deadly virus in a large trial conducted in Guinea, researchers say.

The vaccine trial included nearly 12,000 people during 2015, when new cases of Ebola were still appearing in West Africa.

Among 5,800 people who received the vaccine, no Ebola cases were recorded 10 days or more after vaccination. But 23 cases developed among those who did not get vaccinated, the researchers reported.

The trial was conducted by the World Health Organization (WHO), Guinea’s Ministry of Health and international partners. The results were published Dec. 22 in The Lancet.

“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,” lead author Marie-Paule Kieny said in a journal news release. She is WHO’s assistant director-general for health systems and innovation.

The vaccine is called rVSV-ZEBOV.

Vaccine maker Merck will submit the vaccine for regulatory approval by the end of 2017. The company has promised to make 300,000 doses available for emergency use in the interim.

Further studies are needed to determine the vaccine’s safety in children and other vulnerable groups, such as people with HIV, the researchers said.

The 2014 Ebola outbreak in West Africa sickened more than 28,000 people in Guinea, Sierra Leone and Liberia, and killed more than 11,000.

More information

The U.S. Centers for Disease Control and Prevention has more on Ebola.

Source: HealthDay