Guinea: Ebola vaccine trial

July 2015

Results from an interim analysis of the Guinea Phase III efficacy vaccine trial show that VSV-EBOV (Merck, Sharp & Dohme) is highly effective against Ebola. The independent body of international experts - the Data and Safety Monitoring Board – that conducted the review, advised that the trial should continue.

While the vaccine up to now shows 100% efficacy in individuals, more conclusive evidence is needed on its capacity to protect populations through what is called “herd immunity”. To that end, the Guinean national regulatory authority and ethics review committee have approved continuation of the trial. The technique being used in vaccine trial is called "ring vaccination" which was used in the 1970s to eradicate smallpox. Ring vaccination controls an outbreak by vaccinating all suspected individuals in an area around the outbreak.


Vaccine rVSV Zebov-GP

rVSV Zebov-GP, the Ebola vaccine being trialled is prepared for injection. Guinea
WHO/S. Hawkey

The Ebola vaccine rVSV Zebov-GP is being prepared for injection, Guinea.


Storage of vaccine

A vaccine core is being inserted into the device. Guinea
WHO/S. Hawkey

The Ebola vaccine needs to be kept at a temperature of – 80°C. These vaccine storage devices use jet fuel to keep the right temperature for up to 5 days in the field, even if the storage container is opened several times a day. Here a vaccine core is being inserted into the storage device.


Ebola vaccine lab

Kimberley Steeds, Ebola vaccine trial team member, in the Ebola vaccine laboratory, Donka Hospital in Conakry, Guinea.
WHO/S. Hawkey

Kimberley Steeds, Ebola vaccine trial team member, in the Ebola vaccine laboratory, Donka Hospital in Conakry, Guinea.


  Serum is separated from red blood cells for processing, at the Ebola vaccine lab at Donka Hospital.
WHO/S. Hawkey

Serum is separated from red blood cells for processing, at the Ebola vaccine lab at Donka Hospital.


Mamadouba Conté, working in the Ebola lab at Donka Hospital.
WHO/S. Hawkey

Mamadouba Conté, working in the Ebola lab at Donka Hospital.


Ebola vaccine team

WHO/S. Hawkey

Billo Mamadou Diallo, Karamoko Sonah Camara, Alain Mukendi, Jean Francoi Tolno and Hawa Madi, Team 9 of the WHO Ebola vaccine trial, at work in Katongourou, Guinea.


First person to receive the Ebola vaccine

Mohamed Soumah, 27 years old, was the first person to receive the Ebola vaccine, Guinea
WHO/S. Hawkey

Mohamed Soumah, 27 years old, was the first person to receive the Ebola vaccine. "It wasn't easy. People in the village said that the injection was to kill me. I was afraid. I was the first one to be injected, the very first, here in my village on 23 March 2015. I've been monitored for 3 months and I've had no problems. The last follow-up, 84 days after the vaccination, was all clear".


Consent of vaccine trial participants

WHO Ebola vaccination team, carefully go through the consent process with a participant in the Ebola vaccine trial, Guinea
WHO/S. Hawkey

Nene Aminata Diallo and Gamou Saiman Gaston, from the WHO Ebola vaccination team, carefully go through the consent process with a participant in the Ebola vaccine trial. Obtaining clear consent from participants, that this is a trial, that there are no guarantees, that there may be unexpected consequences from the vaccine, is important in the trial process.


Follow-up sessions with participants

WHO Ebola vaccine trial team follows-up with a trial participant, Katongourou, Guinea
WHO/S. Hawkey

Jean Francoi Tolno and Hawa Madi, Team 9 of the WHO Ebola vaccine trial, at work in Katongourou, Guinea. Here they check the blood pressure and other indicators of a trial participant 30 min after administration of the vaccine.


WHO Ebola vaccine trial team at a follow-up sessions with a trial participant, Guinea
WHO/S. Hawkey

Souare Sekouba and Conde Doussou, WHO vaccine trial team, are following-up with a participant in the trial monitoring his health after the administration of the vaccine. These follow-up sessions take place 3, 9, 21, 42, 63 and 84 days after the vaccination.


WHO vaccine trial team member takes the temperature of a participant in the trial, Guinea
WHO/S. Hawkey

Souare Sekouba, WHO vaccine trial team member, takes the temperature of a participant in the trial using an infrared, non-contact, thermometer, at a follow-up session.


Engaging communities

A village meeting on Ebola, and Ebola vaccine trials, Guinea
WHO/S. Hawkey

A village meeting on Ebola. The elders and religious clerics listen to Dr Sakoba Keita, coordinator of the Guinean Ebola Response.


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