An Ebola vaccine has been shown to provide immunity for up to a year after immunisation in all of those immunised in a new study.

The findings, based on a Phase 1 clinical trial involving 75 healthy subjects, were published in the Journal of the American Medical Association (JAMA).

The study was led by the Oxford Vaccine Group at the University of Oxford. It tested the prime-boost Ebola vaccine regimen being developed by Janssen Vaccines & Prevention B.V. that is based on Janssen’s AdVac technology and MVA-BN technology from Bavarian Nordic A/S. Healthy volunteers were given one vaccine dose to prime their immune system, and the alternative vaccine to boost their immune response. Additional Phase 1, 2 and 3 studies are ongoing to build on these findings.

This is the longest duration follow-up for any heterologous prime-boost Ebola vaccine regimen yet published.

Dr Matthew Snape from the Department of Paediatrics at Oxford, who led the research, said: 'The persistence of vaccine-induced immunity to one year post-immunisation is truly impressive.

'The fact that all participants retained Ebola-specific antibodies to the end of the study does raise hope that this vaccine could induce responses that last for several years.

'This study was conducted in a European population, so it’s important to note that immune responses may differ in a sub-Saharan African population, but these vaccine candidates are currently being assessed in this region.

'Additional research is also needed to explore the persistence of immunity beyond the one year mark and the response to booster doses of vaccine.'

A total of ten clinical studies are being conducted on a parallel track across the US, Europe and Africa in support of potential eventual registration for the Ebola vaccine regimen. The first study of the vaccine regimen in a West African country affected by the recent Ebola outbreak began in Sierra Leone in October 2015.

The full research letter, ‘Immune Responses to Novel Adenovirus Type 26 and Modified Vaccinia Ankara-Vectored Ebola Vaccines at 1 Year,’ can be read in JAMA.