Clinical trials of an experimental Ebola vaccine continue to progress at speed

17 November 2014

Almost 200 people have received a candidate Ebola vaccine in little more than two months in safety trials carried out in the USA, UK, Mali and Switzerland.

The total includes:

  • 20 people at the US National Institutes of Health in Bethesda, Maryland;
  • 80 people at the University of Maryland School of Medicine Center for Vaccine Development in Mali (a joint venture with the Ministry of Health of Mali); and
  • 34 people out of an eventual 120 volunteers will have been vaccinated at the University Hospital of Lausanne by 17 Nov.

In Oxford, UK, the 60th and last healthy volunteer in a trial carried out by the University of Oxford is due to receive the vaccine tomorrow, on Tue 18 Nov.

The Ebola vaccine was developed by the US National Institutes of Health (NIH) and GSK. These first trials in humans have been fast-tracked in response to the current Ebola outbreak.

 If the safety and immunogenicity data from the Phase 1 trials are promising, the expectation is that the vaccine will move into the next phases of study to further evaluate safety as well as effectiveness in protecting against Ebola infection in African countries.

‘The safety data here have looked very satisfactory so far,’ says Professor Adrian Hill of the Jenner Institute at Oxford University, who is leading the Oxford trial. ‘The response we have seen from people coming forward to take part has been remarkable.’

The candidate Ebola vaccine is being co-developed by the US National Institutes of Health (NIH) and GSK against the Zaire species of Ebola, which is the one circulating in West Africa.

It uses a single Ebola virus gene in a chimpanzee adenovirus to generate an immune response. As it does not contain infectious Ebola virus material, it cannot cause a person who is vaccinated to become infected with Ebola.

Pre-clinical research by the NIH and Okairos, a biotechnology company acquired last year by GSK, has indicated that the vaccine protects non-human primates exposed to Ebola without significant adverse effects.

The first volunteer in the UK trial at Oxford University was vaccinated on 17 September, two weeks after the first volunteer in the USA. This allowed further trials in Mali and then Switzerland to begin shortly afterwards in October.

The trialists in Lausanne hope to have a total of 120 subjects vaccinated by beginning of December.

The clinical trial in Mali, being performed by the Center for Vaccine Development of Mali (CVD-Mali), the CVD of the University of Maryland School of Medicine and the Malian Ministry of Health, is providing the only clinical and immune response data so far with the vaccine in West African subjects. By late December 2014, the team should know how the immune responses of Malian health care workers given the vaccine compare to those observed in adults given the vaccine in the UK and Switzerland.

‘This research is a testament to the hard work and cooperation of all the institutions involved,’ says Professor Myron M Levine, director of the Center for Vaccine Development. ‘If this vaccine is proven to work, it could help alter the dynamic of this epidemic by interrupting transmission to the health care workers who are most at risk.’

The Oxford trial is being funded under a £2.8 million grant from the Wellcome Trust, the Medical Research Council (MRC) and the UK Department for International Development (DFID). The consortium’s funding is also enabling GSK to begin manufacturing thousands of additional doses of the vaccine so that if Phase 1 trials are successful, the next phases of the clinical trial programme can begin – which will involve the vaccination of frontline healthcare workers in Ebola affected countries.

The NIH is providing the NIAID/GSK Ebola vaccine for the Oxford study.

For more information please contact the University of Oxford news & information office on +44 (0)1865 280530 or

Photos and B roll of previous vaccinations are available via a DropBox folder

Please note: We remain very restricted in the access and interview requests we are able to offer at the current time. We will do our best to provide good information as and when we can.  

For more information on the Mali trial, please contact the University of Maryland School of Medicine public affairs office on +1 (0) 410-706-7590 or

Notes to Editors:

  • Safety trials with small groups of healthy volunteers are required to ensure that the vaccine does not cause unforeseen side effects, and that it generates a good immune response to Ebola in humans. This is necessary before the vaccine can be rolled out to larger at-risk populations, even on an experimental basis.
  • 60 healthy volunteers are receiving the NIAID/GSK Ebola vaccine in the Oxford University trial. The volunteers receive the vaccine in the upper arm after standard clinical observations are made and blood samples taken.
  • The volunteers use a smartphone app to fill in a diary to record any reactions to the vaccination. They are asked to return to the trial centre the day after the vaccination – and also 7, 10, 14, 28 days, 3 months and 6 months later – for a review of how they are and to give further blood samples.
  • The researchers hope to publish initial data on vaccine safety and the early immune responses the vaccine has stimulated before Christmas. But with volunteers providing blood samples for 6 months after their vaccination, the trial still has a long way to run beyond those initial data.
  • The Oxford research team is currently working to analyse the blood samples from volunteers to understand the immune responses the vaccine generates. A number of assays and tests are done to measure and characterise the antibody and T cell responses the body produces in the weeks and months following vaccination.
  • The NIAID/GSK Ebola vaccine candidate, is based on a novel technology platform developed by Okairos and uses an attenuated strain of chimpanzee cold virus, called chimp adenovirus type 3 (ChAd3). The adenovirus acts as a carrier, or vector, to deliver benign genetic material derived from the Ebola virus Zaire species that has caused the current Ebola outbreak in West Africa. The genetic material contained in the investigational vaccine cannot cause a vaccinated individual to become infected with Ebola. The vaccine candidate delivers the Ebola genetic material to human cells but does not replicate further. Rather, it allows the vaccine recipient’s cells to express a protein, and that protein prompts an immune response in the individual.
  • The Wellcome Trust is the second-highest spending global charitable foundation, dedicated to achieving extraordinary improvements in human and animal health. We support bright minds in biomedical research and the medical humanities, including public engagement, education and the application of research to improve health. We are independent of both political and commercial interests.
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  • Oxford University’s Medical Sciences Division is one of the largest biomedical research centres in Europe, with over 2,500 people involved in research and more than 2,800 students. The University is rated the best in the world for medicine, and it is home to the UK’s top-ranked medical school.
    From the genetic and molecular basis of disease to the latest advances in neuroscience, Oxford is at the forefront of medical research. It has one of the largest clinical trial portfolios in the UK and great expertise in taking discoveries from the lab into the clinic. Partnerships with the local NHS Trusts enable patients to benefit from close links between medical research and healthcare delivery.
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