5 February 2021
A preprint of ongoing work to assess effectiveness of Oxford’s ChAdOx1 coronavirus vaccine shows that the existing vaccine has similar efficacy against the B.1.1.7 ‘Kent’ coronavirus strain currently circulating in the UK to previously circulating variants.
The Oxford University researchers who developed the ChAdOx1-nCoV 19 vaccine have found that it remains effective against one of the new variants of the disease.
The preprint also describes recent analysis showing that vaccination with ChAdOx1 nCoV-19 results in a reduction in the duration of shedding and viral load, which may translate into a reduced transmission of the disease.
Andrew Pollard, Professor of Paediatric Infection and Immunity, and Chief Investigator on the Oxford vaccine trial, said:
‘Data from our trials of the ChAdOx1 vaccine in the United Kingdom indicate that the vaccine not only protects against the original pandemic virus, but also protects against the novel variant, B.1.1.7, which caused the surge in disease from the end of 2020 across the UK.’
Sarah Gilbert, Professor of Vaccinology, and Chief Investigator on the Oxford vaccine trial, said: ‘All viruses accumulate mutations over time, and for influenza vaccines there is a well-known process of global viral surveillance, and selection of strains for an annual update of the vaccines.’
Between 1 October 2020 and 14 January 2021, the researchers used swabs taken from volunteers with both symptomatic and asymptomatic infection enrolled in a phase II/III vaccine efficacy study to work out which strain of coronavirus they had been infected with after receiving either the vaccine or the control.
The protection against symptomatic infection was similar despite lower neutralising antibody titres in vaccinated individuals against the B.1.1.7 variant than the 'Victoria’ strain of virus.
These are the first findings regarding the efficacy of the Oxford vaccine against new variants. Vaccine researchers are already looking at ways to modify the existing vaccines quickly and simply to protect against new variants.
Professor Gilbert continued: ‘Coronaviruses are less prone to mutation than influenza viruses, but we have always expected that as the pandemic continues, new variants will begin to become dominant amongst the viruses that are circulating and that eventually a new version of the vaccine, with an updated spike protein, would be required to maintain vaccine efficacy at the highest level possible
‘We are working with AstraZeneca to optimise the pipeline required for a strain change should one become necessary. This is the same issue that is faced by all of the vaccine developers, and we will continue to monitor the emergence of new variants that arise in readiness for a future strain change.’
Note: these findings are early preliminary data, supplied as a pre-print for information prior to undergoing the peer review process.
Notes to editors:
For further information please contact the University of Oxford press office at email@example.com or on +44 (0)1865 280528
For more about the Oxford vaccine project and team: www.ox.ac.uk/covid-vaccine
Previous papers published on this project:
- Safety and efficacy of the ChAdOx1 nCoV-19 vaccine (AZD1222) against SARS-CoV-2: an interim analysis of four randomised controlled trials in Brazil, South Africa, and the UK.
- M Voysey, S A Costa Clemens, S A Madhi, L Y Weckx, P M Folegatti, P K Aley, et al.
- The Lancet 2020.
- Safety and immunogenicity of ChAdOx1 nCoV-19 vaccine administered in a prime-boost regimen in young and old adults (COV002): a single-blind, randomised, controlled, phase 2/3 trial. M N Ramasamy, A M Minassian, K J Ewer, A L Flaxman, P M Folegatti, D R Owens, et al. The Lancet 2020.
- Safety and immunogenicity of the ChAdOx1 nCoV-19 vaccine against SARS-CoV-2: a preliminary report of a phase 1/2, single-blind, randomised controlled trial. P Folegatti, K Ewer, C Green, A Douglas, A Hill, T Lambe, S Gilbert, A Pollard et al. The Lancet 2020.
- Evaluation of the immunogenicity of prime-boost vaccination with the replication-deficient viral vectored COVID-19 vaccine candidate ChAdOx1 nCoV-19. Graham, Lambe et al. NPJ Vaccines 2020.
- ChAdOx1 nCoV-19 vaccine prevents SARS-CoV-2 pneumonia in rhesus macaques. van Doremalen, Lambe et al. Nature. 2020.
- A booster dose enhances immunogenicity of the COVID-19 vaccine candidate ChAdOx1 nCoV-19 in aged mice. Lambe, Linterman et al. Med (2020).
- Intranasal ChAdOx1 nCoV-19/AZD1222 vaccination reduces shedding of SARS-CoV-2 D614G in rhesus macaques. Lambe, Munster et al. Pre-print bioRxiv (2021).
- ChAdOx1 nCoV-19 protection against SARS-CoV-2 in rhesus macaque and ferret challenge models. Lambe, Spence et al. Pre-print ResearchSquare (2021).
- Single Dose Administration, And The Influence Of The Timing Of The Booster Dose On Immunogenicity and Efficacy Of ChAdOx1 nCoV-19 (AZD1222) Vaccine. M Voysey, S A Costa Clemens et al. Pre-Print Preprints with THE LANCET (2021)
For detailed information about the vaccine trial: covid19vaccinetrial.co.uk
Images: Credit: University of Oxford, John Cairns
- Vaccine PI profiles: https://www.dropbox.com/sh/jpql3ofnoal1gz7/AABY1Kt9NytSrLcswhsK-SZGa?dl=0
- Oxford Vaccine Vial: https://www.dropbox.com/sh/uj7itywvcdvoudt/AADjI_sgCzcVzPpdvbUqrqcea?dl=0
- Downloadable researcher interviews and b-roll for video editors and broadcast: https://vimeo.com/showcase/7803812, contact the News Office for a password
NOTE: These are for downloading and editing by media outlets, not for uploading or using wholesale.
- Short explainer video for social media or embed: https://youtu.be/xHJ_RqeXXy0
About the Oxford COVID-19 vaccine
ChAdOx1 nCoV-19, now known as AZD1222 co-invented by the University of Oxford and its spin-out company, Vaccitech, is being trialled by the University’s Jenner Institute and Oxford Vaccine Group. The team started working to develop a vaccine against coronavirus in January 2020.
Developed at the Jenner Institute, the recombinant adenovirus vector ChAdOx1 nCoV-19 uses a viral vector based on a weakened version of the common cold virus (adenovirus) containing the genetic material of SARS-CoV-2 spike protein. After vaccination, the surface spike protein is produced, which primes the immune system to attack COVID-19 if it later infects the body.
Over 50,000 people to date have taken part in clinical trials of The ChAdOx1 nCoV-19 vaccine sponsored by the University of Oxford and AstraZeneca, and many more have received the vaccine through public vaccination programmes following emergency use licensure. It has been shown to be safe and well tolerated, although it can cause temporary side effects, such as a temperature, flu-like symptoms, headache or sore arm.
The potential vaccine entered Phase III clinical trials in May to study safety and efficacy in healthy volunteers. In total, nearly 24,000 volunteers have joined the University of Oxford sponsored trial, in sites around the UK (approximately 12,000 volunteers), Brazil (approximately 10,000 volunteers) and South Africa (approximately 2,000 volunteers). Interim efficacy and safety data were published in The Lancet in December, including an extensive safety database of over 74,000 ‘person months’ of safety data follow-up.
Our partners, AstraZeneca, have committed to delivering billions of doses of its COVID-19 vaccine across the globe in a broad, equitable, and timely way at no profit during the pandemic. This includes an agreement with the European Commission to supply up to 400 million doses, starting in early 2021 following the regulatory approval from the European Medicines Agency, with tens of millions of doses due to be supplied in February and March.
For more information on this commitment, visit: https://www.astrazeneca.com/content/astraz/media-centre/articles/2021/astrazenecas-covid-19-vaccine-european-union-supply-commitment.html
Not for profit information:
As part of our agreement with our partner AstraZeneca, the vaccine will be supplied on a not-for-profit basis for the duration of the pandemic and in perpetuity for low- and middle-income countries, with any future royalties received by the University of Oxford being re-invested in the medical sciences.
This trial is funded by the National Institute for Health Research, UK Research and Innovation, the Bill & Melinda Gates Foundation, the Lemann Foundation, and the South African Medical Research Council. We are grateful to the NIHR infrastructure provided through the NIHR Biomedical Research Centres and the NIHR Clinical Research Network at the UK study sites.
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