Publish date: 23 November 2020

The University of Oxford, in collaboration with AstraZeneca plc, today announces interim trial data from its ‘Phase 3’ trials which involved UCLH that show its candidate vaccine is effective at preventing COVID-19 and offers a high level of protection.

UCLH has made a significant contribution to the study, where efforts have been led by Professor Vincenzo Libri, Director of the National Institute for Health Research UCLH Clinical Research Facility. The NIHR UCLH Biomedical Research Centre has supported delivery of the trial, which was set up by the UCLH/UCL Joint Research Office.

The analysis, including 131 Covid-19 cases of the Covid-19 vaccine, indicates that the vaccine is 70.4% effective when combining data from two dosing regimens.

In the two dosing regimens vaccine efficacy was 90% in one and 62% in the other. The ‘higher efficacy’ regime used a halved first dose and standard second dose.

There is an early indication that the vaccine could reduce virus transmission from an observed reduction in asymptomatic infections. There were no hospitalised or severe cases in anyone who received the vaccine.

Researchers now have a large safety database from over 24,000 volunteers from clinical trials in the UK, Brazil and South Africa, with follow up since April.

Crucially, the vaccine can be easily administered in existing healthcare systems, stored at ‘fridge temperature’ (2-80C) and distributed using existing logistics.

Large scale manufacturing is ongoing in over 10 countries to support equitable global access.

Professor Andrew Pollard, Director of the Oxford Vaccine Group and Chief Investigator of the Oxford Vaccine Trial, said: “These findings show that we have an effective vaccine that will save many lives. Excitingly, we’ve found that one of our dosing regimens may be around 90 % effective and if this dosing regime is used, more people could be vaccinated with planned vaccine supply. Today’s announcement is only possible thanks to the many volunteers in our trial, and the hard working and talented team of researchers based around the world.”

Professor Sarah Gilbert, Professor of Vaccinology at the University of Oxford, said: “The announcement today takes us another step closer to the time when we can use vaccines to bring an end to the devastation caused by SARS-CoV-2. We will continue to work to provide the detailed information to regulators. It has been a privilege to be part of this multi-national effort which will reap benefits for the whole world.”

UCLH’s Professor Libri said: “This is a very important milestone in our efforts to tackle Covid-19. I want to say a big thank you to all the volunteers who have taken part in this study including staff at UCLH, and to all staff across UCLH who have helped to deliver this study and whose dedication has made this work possible.”

UCLH Chief Executive Professor Marcel Levi said: “I am proud that UCLH has been involved in this study and proud of the contribution our staff have made, both in terms of running the trial or taking part in it. I hope these results offer hope to staff – who have been under enormous and unprecedented pressure during this crisis – about our prospects of ending the pandemic.”

UCLH Director of Research Professor Bryan Williams said: “We have known from the start of the pandemic that the development of vaccines is our best hope of beating Covid-19, and we are delighted to be contributing to this global effort. Our significant involvement in this study reflects our research expertise, underpinned by our Biomedical Research Centre, and our status as a Research Hospital.”

The preliminary data indicate that the vaccine is 70.4% effective, with tests on two different dose regimes showing that the vaccine was 90% effective if administered at a half dose and then at a full dose, or 62% effective if administered in two full doses.

Additional cases are expected to accrue by the time of the final analysis and future analyses will determine the duration of protection. No serious safety events related to the vaccine have been identified.

Oxford will now support AstraZeneca in submitting both the interim Phase 3 efficacy data and the extensive safety data to all regulators across the world, including in the UK, Europe and Brazil for independent scrutiny and product approval, including for emergency use. Many of these regulators have been reviewing the trial data on a rolling basis during the trial.

In parallel, Oxford is submitting the full analysis of the Phase 3 interim data for independent scientific peer review and publication.

The clinical trials, enrolling over 24,000 participants from diverse racial and geographical groups in the UK, Brazil and South Africa, will now continue to final analysis. Further trials are being conducted in the United States, Kenya, Japan and India and the trial team expect to have under 60,000 participants by the end of the year. These trials will provide regulators with further information about the efficacy and safety of the Oxford candidate vaccine, including its ability to both protect against and stop the transmission of COVID-19.

The Oxford vaccine (ChAdOx1 nCoV-19) is made from a virus, which is a weakened version of a common cold virus (adenovirus), that has been genetically changed so that it is impossible for it to grow in humans. 

Adenovirus vaccines have been researched and used extensively for decades and have the significant benefit that they are stable, easily manufactured, transported and stored at domestic fridge temperature (2-8 degrees C). This means they can be easily distributed using existing medical facilities such as doctor’s surgeries and local pharmacies, allowing for the vaccine, if approved, to be deployed very rapidly.