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Wits University statement on Oxford Covid-19 vaccine results in UK and Brazil populations

- Wits University

Scientists at Wits University are encouraged by results announced today by colleagues at the University of Oxford in collaboration with AstraZeneca.

Scientists at Wits University, which leads the South African trial of the ChAdOx1 Covid-19 vaccine developed by the University of Oxford, commented on the findings announced by Oxford/AstraZeneca following a pooled interim analysis of the Phase 3 arms of the UK and Brazil studies of this vaccine.

The findings indicate that the vaccine is 70.4% effective in protecting against Covid-19 in UK and Brazil when combining data from two dosing regimens.

In the two different dose 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.

Early indications are that the vaccine could reduce virus transmission from an observed reduction in asymptomatic infections.

Crucially, the vaccine can be easily administered in existing healthcare systems, stored at ‘fridge temperature’ (2-8 degrees Celcius), and distributed using existing logistics.

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

Although these interim results do not include analysis of South African participants in the global trial, they suggest similarly encouraging results can be expected here.

Professor Shabir Madhi, Executive Director of the Vaccines and Infectious Diseases Analytics (VIDA) Research Unit at Wits, which leads the trials in SA, said: “The results from this study add further hope that accessing vaccines to fight the Covid-19 pandemic are fast becoming a reality.The results from this study are intriguing, in that a dose-sparing regimen may inadvertently end up being more protective. This has implications not only for the cost of the vaccine, but also how many more people could possibly be vaccinated in the near future when vaccine supply is likely to be constrained.

Also, the ability to scale up production of this vaccine, and it only needing to be stored at 2-8oC, would greatly assist in the deployment of the vaccine in low and middle income countries. The cost of this vaccine is also anticipated to be much cheaper than other Covid-19 vaccines that have recently been shown to be efficacious.”

The trial in South Africa has enrolled 2,100 participants and analysis of the trial in South Africa is expected after an adequate number of Covid-19 cases have been identified.

Madhi emphasised the importance of testing the vaccine in diverse populations, such as South Africa: “The results of the study from South Africa remain of global interest, and to inform recommendations on Covid-19 vaccine in Africa, as the Covid-19 experience in South Africa has been very different to the UK. As for many other vaccines, genetic factors and local conditions could also affect the performance of the vaccine in different populations.

The results of the pooled analysis from UK and Brazil creates optimism that we will also show protection against COVID-19 in the South African study, where participants are still being followed-up.

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.”

Further information:

About the South African Oxford Covid-19 vaccine trial:

South African Oxford Covid-19 vaccine trial FAQs:

About the ChAdOx1 nCoV-19 vaccine research at:

About the Oxford Covid-10 vaccine trial: