100% of pigs protected from African swine fever in Pirbright vaccine trial
21st May 2020 / By Alistair Driver
In what has been described as a 'huge step forward', a study at the Pirbright Institute has shown that 100% of pigs immunised were protected from a lethal dose of ASF virus (ASFV).
The team at the Surrey research institute created what is known as a vectored vaccine by inserting eight strategically selected ASFV genes into a non-harmful virus, known as a vector. Vectors are used to deliver the genes to pig cells where they produce viral proteins that prime the pig immune system to rapidly respond to an ASF infection.
The study, published in Vaccines, showed the combination of eight virus genes protected pigs from severe disease after challenge with an otherwise fatal strain of ASFV. However, clinical signs of disease did develop.
This is the first time that a vectored vaccine has shown a protective effect against ASF, according to the researchers, who stressed that further development of the vaccine is still needed.
But if it is successful - and there was no indication given of a timescale - the vaccine would enable the differentiation of infected animals from those that have received a vaccine (DIVA). This would allow vaccination programmes to be established without sacrificing the ability to trade, they said.
Dr Chris Netherton, head of Pirbright’s ASF Vaccinology Group, said: “Demonstrating that our vaccine has the potential to fully protect pigs against ASF is a huge step in our vaccine development programme.
“We have already begun work to refine the genes included in the vaccine to improve its effectiveness and provide more protection.”
Christine Middlemiss, the UK’s Chief Veterinary Officer, described the findings as ‘a very encouraging breakthrough, which means we are one step closer to safeguarding the health of our pigs and the wider industry’s role in global food supply from ASF'.
“While there has never been an outbreak of African swine fever in the UK, we are not complacent and already have robust measures in place to protect against animal disease outbreaks,” she said.
This research was funded by the Defra and the Biotechnology and Biological Sciences Research Council (BBSRC), part of UK Research and Innovation (UKRI).