Canadian Ebola vaccine looks promising

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An Ebola vaccine developed by Public Health Agency of Canada and currently in phase III trials in Guinea has shown promising results and chances are it could be the vaccine the world is waiting for since the outbreak.

Though the results are based on an interim analysis, the independent body of international experts – the Data and Safety Monitoring Board – that conducted the review has said that the VSV-EBOV (Merck, Sharp & Dohme) is highly effective against the deadly disease. The body has suggested that the trails must continue.

Dr Margaret Chan, Director-General of the World Health Organization, pegged it as extremely promising development and credited the Guinean Government, the people living in the communities and WHO partners in this project for the progress made.

The preliminary results indicate that the vaccine shown 100 per cent efficacy in individuals; however, more conclusive evidence is needed on its capacity to protect populations through what is called “herd immunity”.

The strategy employed during the vaccination is dubbed as a ‘ring’ vaccination wherein all those people who have come in contact with an infected person are vaccinated. This effectively creates a protective ‘ring’ and stops the virus from spreading further.

The Guinea vaccination trial began in affected communities on 23 March 2015 to evaluate the efficacy, effectiveness and safety of a single dose of the vaccine VSV-EBOV by using a ring vaccination strategy. To date, over 4,000 close contacts of almost 100 Ebola patients, including family members, neighbours, and co-workers, have voluntarily participated in the trial.

The trial stopped randomisation on 26 July to allow for all people at risk to receive the vaccine immediately, and to minimize the time necessary to gather more conclusive evidence needed for eventual licensure of the product. Until now, 50 per cent of the rings were vaccinated 3 weeks after the identification of an infected patient to provide a term of comparison with rings that were vaccinated immediately. This now stops. In addition, the trial will now include 13 to 17-year-old and possibly 6 to 12-year-old children on the basis of new evidence of the vaccine’s safety.

“In parallel with the ring vaccination, we are also conducting a trial of the same vaccine on frontline workers,” said Bertrand Draguez, Medical Director at Médecins sans Frontières. “These people have worked tirelessly and put their lives at risk every day to take care of sick people. If the vaccine is effective, then we are already protecting them from the virus. With such high efficacy, all affected countries should immediately start and multiply ring vaccinations to break chains of transmission and vaccinate all frontline workers to protect them.”

The trial is being implemented by the Guinean authorities, WHO, Médecins sans Frontières (MSF) and the Norwegian Institute of Public Health, with support from a broad partnership of international and national organizations.

“This is a remarkable result which shows the power of equitable international partnerships and flexibility,” said Jeremy Farrar, Director of the Wellcome Trust, one of the funders of the trial. “This partnership also shows that such critical work is possible in the midst of a terrible epidemic. It should change how the world responds to such emerging infectious disease threats. We, and all our partners, remain fully committed to giving the world a safe and effective vaccine.”

“This record-breaking work marks a turning point in the history of health R&D,” said Assistant Director-General Marie-Paule Kieny, who leads the Ebola Research and Development effort at WHO. “We now know that the urgency of saving lives can accelerate R&D. We will harness this positive experience to develop a global R&D preparedness framework so that if another major disease outbreak ever happens again, for any disease, the world can act quickly and efficiently to develop and use medical tools and prevent a large-scale tragedy.”

The preliminary results are published in the British journal The Lancet.