Final trial results confirm Ebola vaccine provides high protection against disease

Based on promising data from initial clinical trials in late 2014, WHO with the Health Ministry of Guinea, Médecins Sans Frontières (MSF), Epicentre and The Norwegian Institute of Public Health (NIPH), will launch a Phase III trial in Guinea on 7 March to test the VSV-EBOV vaccine for efficacy and effectiveness to prevent Ebola. The vaccine was developed by the Public Health Agency of Canada. A second vaccine will be tested in a sequential study, as supply becomes available.

“We have worked hard to reach this point,” said WHO Director-General, Dr Margaret Chan. “There has been massive mobilization on the part of the affected countries and all partners to accelerate the development and availability of proven interventions. If a vaccine is found effective, it will be the first preventive tool against Ebola in history.” Vaccination will take place in areas of Basse Guinée, the region that currently has the highest number of cases in the country.

The trial strategy adopted will be “ring vaccination”, based on the approach used to eradicate smallpox in the 1970s. This involves the identification of a newly diagnosed Ebola case – the “index case” – and the tracing of all his/her contacts. The contacts are vaccinated if they give their consent.

“The Ebola epidemic shows signs of receding but we cannot let down our guard until we reach zero cases,” said Assistant Director-General Marie-Paule Kieny, who leads the Ebola Research and Development effort at WHO. “An effective vaccine to control current flare-ups could be the game-changer to finally end this epidemic and an insurance policy for any future ones.” The objectives of the trial are two-fold: to assess if the vaccine protects the contacts who were vaccinated and if vaccinating the contacts will create a buffer - or ring of protected individuals - around the index case to prevent further spread of the infection. Vaccination will also be proposed to frontline workers in the area where the trial will take place.

Canadian governmental institutions are supporting the trial through the provision of critical training and support to the African research teams conducting the trial, in addition to scientific advice. In the last six months WHO has convened a series of emergency consultations with scientists, ethicists, regulators and policy makers to identify potential preventive and therapeutic products to help stem the… An experimental Ebola vaccine was highly protective against the deadly virus in a major trial in Guinea, according to results published today 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 5837 people who received the vaccine, no Ebola cases were recorded 10 days or more after vaccination.