Collaborative research has shown that a new vaccine, ChAdOx1 RVF, is effective at protecting pregnant sheep and goats from Rift Valley fever (RVF), a debilitating disease that can also be transmitted to humans. Scientists from The Pirbright Institute worked with The Jenner Institute at the University of Oxford, Wageningen Bioveterinary Research in the Netherlands, BioVacc Consulting Ltd and the KEMRI-Wellcome Trust Research Programme in Kenya on this project. The team’s work will progress the development of the vaccine, which could be the first to be used against both a human and animal disease.
ChAdOx1 RVF was previously shown to be safe and effective at protecting animals, and has since been scheduled for human trials. However, its safety in pregnant animals had not been verified. This collaborative study, published in npj Vaccines, has shown that pregnant sheep and goats immunised with a single dose of ChAdOx1 RVF remain healthy and suffer no pregnancy losses after challenge with a virulent strain of RVF virus. The protection was more robust in sheep than goats, despite the similar levels of immune response induced. This suggests that protection mechanisms against RVF could differ between livestock species.
The research shows that ChAdOx1 RVF overcomes drawbacks that current veterinary RVF vaccines experience, such as causing pregnancy complications or requiring multiple booster vaccinations. ChAdOx1 RVF also generates a rapid immune response and allows diagnostic tests to differentiate between infected and vaccinated animals (DIVA). These properties make this vaccine well suited for tackling outbreak situations and could limit the circulation of RVF amongst animals and people.
RVF is spread across Africa and the Arabian Peninsula and is caused by a virus that infects livestock such as sheep, goats, cattle and camels. Infection of animals with Rift Valley fever virus (RVFV) results in high mortality and poor outcomes during pregnancy, such as stillbirths, foetal malformations and abortions. It also poses a severe threat to human health but there is currently no licenced human vaccine available. People can contract the disease through contact with contaminated tissues and fluids of livestock, as well as being bitten by infected mosquitoes.
Dr Anna Stedman, lead author, said: “Our study has provided further evidence of the vaccine’s effectiveness and safety. Ensuring ChAdOx1 RVF can be used in pregnant animals will help livestock owners to protect their animals in the event of an outbreak, which in turn will reduce their own risk of infection.”
Professor Bryan Charleston, Director of The Pirbright Institute, said: “This research will aid the development of ChAdOx1 RVF for human use, and for the first time we may see a vaccine that can be deployed against the same virus in both animals and humans.”
Professor George Warimwe, leader of the Rift Valley Fever Vaccine Programme at the University of Oxford said: “This has been a tremendous collaborative achievement. The excellent safety profile of the vaccine in pregnant livestock will support further development of the product for use in both livestock and humans.”
This research was funded by the Department of Health and Social Care as part of the UK Vaccine Network (UKVN), a UK Aid programme to develop vaccines for diseases with epidemic potential in low and middle-income countries (LMICs).
Notes to editors
RVF is an ‘outbreak’ virus; it is possible to go 5-10 years without an appearance, and the last outbreak was in Wajir, Kenya in 2018. It is spread mainly by mosquitoes of the Aedes genus, but some Culex species can also transmit the virus.
The ChAdOx1 RVF vaccine was made by researchers at The Jenner Institute, University of Oxford and the study was funded by the UK Department of Health and Social Care.
Pirbright researchers are currently conducting ChAdOx1 RVF field trials in Kenya with The Jenner Institute, University of Oxford, the KEMRI-Wellcome Trust Research Programme in Kenya and International Livestock Research Institute (ILRI) in Kenya. Phase I clinical trials in humans are also planned to take place in Oxford and Uganda.
The DOI for the journal article is 10.1038/s41541-019-0138-0. This will become active after the embargo lifts.
About The Pirbright Institute
The Pirbright Institute is a world leading centre of excellence in research and surveillance of virus diseases of farm animals and viruses that spread from animals to humans. Based in the UK and receiving strategic funding from the Biotechnology and Biological Sciences Research Council (BBSRC UKRI), the Institute works to enhance capability to contain, control and eliminate these economically and medically important diseases through highly innovative fundamental and applied bioscience.
With an annual income in excess of £35 million from grants and commercial activity, and a total of £12.6 million strategic investment from BBSRC during 2018-2019, the Institute contributes to global food security and health, improving quality of life for animals and people.
For more information about The Pirbright Institute see: www.pirbright.ac.uk
About KEMRI-Wellcome Trust Research Programme
The Kenya Medical Research Institute (KEMRI)-Wellcome Trust Research Programme was formally established in 1989, and is a partnership between KEMRI, Oxford University and the Wellcome Trust. It conducts basic, epidemiological and clinical research in parallel, with results feeding directly into local and international health policy, and aims to expand the country's capacity to conduct multidisciplinary research that is strong, sustainable and internationally competitive. www.kemri-wellcome.org
About the UK Vaccine Network
The Department for Health and Social Care (DHSC) is the UK Government department that is responsible for helping people to live more independent, healthier lives for longer. This investment is part of the UK Vaccine Network (UKVN). UKVN was established by DHSC to provide funding to support the development of promising vaccines and vaccine technologies that will help combat infectious diseases that have epidemic potential in low and middle-income countries (LMICs). UKVN is a £120m UK Aid investment, which means all projects funded must support research primarily and directly for the benefit of people in LMICs.