- GSK/NIH Ebola vaccine is well tolerated and generates an immune response
- Larger trials in West Africa are needed to tell whether immune responses are large enough to protect against Ebola infection and disease
- Results from Oxford and other safety trials will inform plans for larger trials
The first results from a trial of a candidate Ebola vaccine at Oxford University suggest the vaccine has an acceptable safety profile at the doses tested, and is able to generate an immune response.
‘The vaccine was well tolerated. Its safety profile is pretty much as we had hoped,’ said Professor Adrian Hill of the Jenner Institute at Oxford University, who led the trial.
The researchers say these results suggest the vaccine is suitable for further testing in West Africa during the current outbreak, with the aim of determining whether the vaccine offers protection against Ebola.
The candidate Ebola vaccine is being co-developed by the US National Institutes of Health (NIH) and GSK against the Zaire strain of Ebola, which is the one circulating in West Africa. The first doses for use in large scale trials in West Africa have been delivered to Liberia by GSK.
The vaccine 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.
The Oxford University trial is one of several safety trials of the GSK/NIH vaccine candidate – in the USA, UK, Mali and Switzerland – that have been fast-tracked in response to the Ebola outbreak in West Africa.
The UK trial is funded by the Wellcome Trust, Medical Research Council (MRC) and Department for International Development (DFID). The NIH is providing the NIH/GSK Ebola vaccine for the Oxford University study.
The initial findings are published in the New England Journal of Medicine (NEJM).
60 healthy volunteers were vaccinated at the University of Oxford’s Jenner Institute between 17 September and 18 November.
The NEJM paper reports safety data and immune responses for the volunteers for 28 days after immunisation. Follow-up of the vaccinees will continue beyond these initial data until six months after the volunteers received the experimental vaccine.
The volunteers received one of three different vaccine doses. 20 volunteers received a low dose vaccine (1 x 10^10 viral particles (vp)); 20 volunteers a middle dose (2.5 x 10^10 vp); and 20 volunteers a high dose (5 x 10^10 vp).
The experimental vaccine was well tolerated at all three doses. The majority of adverse events reported by the volunteers were mild in severity. Two people experienced a moderate fever within 24 hours of receiving the vaccine, but this passed within a day.