Ebola Vaccine Programme
In August 2014, the World Health Organisation (WHO) declared the current Ebola outbreak in West Africa a “public health emergency of international concern” . Following consultation with scientists, the WHO moved to fast-track clinical trials of two available candidate Ebola vaccines through an international consortium including the MRC, Wellcome Trust and the UK Department for International Development. One of these vaccines, ChAd3 EBOZ, co-developed by GSK and the NIH, is being tested in clinical trials at the Jenner Institute.
The ChAd3 EBOZ vaccine uses a chimpanzee adenovirus to stimulate an immune response in the vaccinated volunteer against the glycoprotein from the Zaire strain of Ebola, which is responsible for the current outbreak . Adenoviruses from chimpanzees have been used successfully to produce protective immunity against malaria and are safe for use in humans [3, 4]. A study in monkeys using this vaccine resulted in 100% protection against the Ebola virus through production of antibody and T cell responses . NIAID are testing this same vaccine in the US, in addition to a related vaccine that is designed to protect against two Ebola species (Ebola Zaire and Ebola Sudan).
A single gene from the Ebola virus is transferred into the genetic material of the adenovirus vector using DNA technology. When administered to a volunteer, the adenovirus produces the protein from the gene along with its own proteins. The human immune system responds to the protein making immune cells and antibodies against the Ebola virus. If the person then encounters the real Ebola virus, the immune system will recognise that single protein and the immune cells and antibodies will destroy the infection before the person becomes ill.
We are recruiting 60 healthy volunteers for this Phase I clinical trial and will be evaluating safety and immunogenicity, in particular whether immune responses in humans are comparable to those observed in the protected monkeys. Volunteers will be split into groups of 20 that will receive different doses of the vaccine so researchers can determine the best dose to use in terms of both safety and immunogenicity.
It is hoped that the phase 1 trials will be completed by end 2014, after which deployment of the vaccine in West Africa could be fast-tracked if it proves to be safe and immunogenic.
The trial will be based at the Oxford Vaccine Centre at the Churchill Hospital.
1. Rampling, T., Ewer K., et al., A Monovalent Chimpanzee Adenovirus Ebola Vaccine - Preliminary Report. N Engl J Med, 2015 Jan 28. DOI: 10.1056/NEJMoa1411627
2. WHO. Ebola outbreak response: maps 2014 [cited 2014 14/10/2014]; Available from: http://www.who.int/csr/disease/ebola/maps/en/.
3. Team, W.H.O.E.R., Ebola Virus Disease in West Africa - The First 9 Months of the Epidemic and Forward Projections. N Engl J Med, 2014.
4. Ewer, K.J., et al., Protective CD8+ T-cell immunity to human malaria induced by chimpanzee adenovirus-MVA immunisation. Nature communications, 2013. 4: p. 2836.
5. O'Hara, G.A., et al., Clinical assessment of a recombinant simian adenovirus ChAd63: a potent new vaccine vector. The Journal of infectious diseases, 2012. 205(5): p. 772-81.
6. Stanley, D.A., et al., Chimpanzee adenovirus vaccine generates acute and durable protective immunity against ebolavirus challenge. Nat Med, 2014. 20(10): p. 1126-9.