EbolaFinal trial results confirm Ebola vaccine provides high protection against disease

Published 27 December 2016

Since Ebola virus was first identified in 1976, sporadic outbreaks have been reported in Africa. But the 2013-2016 West African Ebola outbreak, which resulted in more than 11,300 deaths, highlighted the need for a vaccine. An experimental Ebola vaccine was highly protective against the deadly virus in a major trial in Guinea, according to results published in The Lancet. The vaccine is the first to prevent infection from one of the most lethal known pathogens, and the findings add weight to early trial results published last year.

All primates can be infected with the Ebola virus // Source: theconversation.com

An experimental Ebola vaccine was highly protective against the deadly virus in a major trial in Guinea, according to results published in The Lancet. The vaccine is the first to prevent infection from one of the most lethal known pathogens, and the findings add weight to early trial results published last year.

The vaccine, called rVSV-ZEBOV, was studied in a trial involving 11,841 people in Guinea during 2015. Among the 5,837 people who received the vaccine, no Ebola cases were recorded ten days or more after vaccination. In comparison, there were twenty-three cases ten days or more after vaccination among those who did not receive the vaccine.

The trial was led by the World Health Organization, together with Guinea’s Ministry of Health and other international partners.

“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 defenceless,” said Dr Marie-Paule Kieny, WHO’s Assistant Director-General for Health Systems and Innovation, and the study’s lead author.

The Lancet reports that the vaccine’s manufacturer, Merck, Sharpe & Dohme, this year received Breakthrough Therapy Designation from the United States Food and Drug Administration and PRIME status from the European Medicines Agency, enabling faster regulatory review of the vaccine once it is submitted.

Since Ebola virus was first identified in 1976, sporadic outbreaks have been reported in Africa. But the 2013-2016 West African Ebola outbreak, which resulted in more than 11,300 deaths, highlighted the need for a vaccine.

The trial took place in the coastal region of Basse-Guinée, the area of Guinea still experiencing new Ebola cases when the trial started in 2015. The trial used an innovative design, a so-called “ring vaccination” approach - the same method used to eradicate small pox.

When a new Ebola case was diagnosed, the research team traced all people who may have been in contact with that case within the previous 3 weeks, such as people who lived in the same household, were visited by the patient, or were in close contact with the patient, their clothes or linen, as well as certain “contacts of contacts”. A total of 117 clusters (or “rings”) were identified, each made up of an average of 80 people.