Pirbright begins testing potential Covid-19 vaccines on animals

The UK’s Pirbright Institute is to begin testing new coronavirus vaccines on animals to help combat the Covid-19 pandemic.

Working in collaboration with researchers at the University of Oxford and Public Health England, the team of scientists at Pirbright will begin testing new vaccines for their ability to induce protective antibodies against SARS-CoV-2, the virus responsible for Covid-19.

Pirbright has a long history of research on livestock coronaviruses including porcine coronaviruses, which affect pigs, and infectious bronchitis virus (IBV) that affects poultry. However, this marks the first time the institute has carried out research on human coronaviruses.

The animal studies will be funded by The Pirbright Institute from BBSRC UK Research and Innovation (UKRI) Institute Strategic Programme Grants.

Testing potential vaccines

The vaccines will include the chimpanzee adenovirus vaccine vector (ChAdOx1), which is soon to enter human phase I clinical trials and has been used to create vaccines for diseases like Ebola, Middle Eastern respiratory syndrome (MERS) and flu.

The potential vaccines have been developed at Oxford and will contain the spike protein from SARS-CoV-2, the protein against which protective antibodies are generated in infected patients.

Pirbright scientists will measure the level of antibodies produced after vaccination of pigs and assess whether the antibodies can block SARS-CoV-2 from infecting cells, thereby preventing infection.

The pig immune system shares significant similarities to that of humans, so a good response to a vaccine in pigs will help to predict the success of vaccines for human use.

Paving the way for a human vaccine

Researchers will also test the safety of the new vaccines and monitor whether any adverse effects are observed.

This work will inform the development of vaccines that are both effective and safe for humans. If successful, the next step would be to begin human trials, although a useable vaccine is still many months away.

Pirbright is one of the few facilities in the world that has the expertise in animal immunology and the state-of-the-art virology facilities required to undertake this type of work.

Prof. Bryan Charleston, director of The Pirbright Institute, said: “The ChAdOx1 vector vaccine developed by Oxford will be used in this SARS-CoV-2 vaccine research as it can generate a strong immune response with just a single dose.

The vaccine vector is non-replicating which means it cannot cause ongoing infection in an individual, making it safer to use for those with underlying health conditions like diabetes.

“This approach has been used in other vaccines and we are hopeful that this research will enable this vaccine to move into the next stage of human testing.”

“This work is a fantastic collaboration between world-leading medical and veterinary scientists in immunology, virology and molecular biology.

Dr. Toby Tuthill, head of the Virus Programme at Pirbright, added: “It will provide an evaluation of new SARS-CoV-2 vaccines in a relevant model and will also generate a panel of antibody-based tools which will help us understand virus structure and how it stimulates the immune response. These antibodies could also be developed as additional novel therapeutics to treat COVID-19.”