A vial of AstraZeneca's COVISHIELD coronavirus disease vaccine. Picture: Shwe Paw Mya Tin/Reuters
A vial of AstraZeneca's COVISHIELD coronavirus disease vaccine. Picture: Shwe Paw Mya Tin/Reuters

AstraZeneca vaccine trial in SA confirms 100% protection against severe disease and hospitalisation

By Kelly Jane Turner Time of article published Feb 3, 2021

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The AstraZeneca Covid-19 vaccine has been shown to provide full protection against severe disease and keeps people out of hospital more than three weeks after the first dose – according to phase three clinical trial results from the UK, Brazil and South Africa.

Part of the trial consisted of over 1 000 South African participants.

The study, which was published as a pre-print in health journal The Lancet, found the vaccine gives around 76% protection after the first dose and after an inter-dose interval of 12 weeks or more, the vaccine efficacy increased to 82%.

South Africa received its first 1 million doses of the Covid-19 Oxford University-AstraZeneca vaccine from the Serum Institute of India (SII) on Monday.

However, the country will still need to wait another 10-14 days until the first dose is administered as quality checks will be under way before the start of the three-phase immunisation campaign.

Researchers from the trials led by Oxford University and AstraZeneca said the analysis also showed the potential for the vaccine to reduce asymptomatic transmission of the virus.

Over 17 thousand seronegative trial participants — or people who tested negative for the virus — were eligible for inclusion in the efficacy analysis. In the United Kingdom, close to nine thousand people were tested, six thousand in Brazil, and 1 476 people in South Africa.

In an AstraZeneca press release, executive vice president BioPharmaceuticals R&D, Sir Mene Pangalos, said the analysis reconfirmed the vaccine prevented severe disease and kept people out of hospital.

“In addition, extending the dosing interval not only boosts the vaccine’s efficacy, but also enables more people to be vaccinated upfront. Together with the new findings on reduced transmission, we believe this vaccine will have a real impact on the pandemic.”

Chief Investigator of the Oxford Vaccine Trial, and co-author of the paper, Professor Andrew Pollard, said: “It helps to support the policy recommendation made by the Joint Committee on Vaccination and Immunisation for a 12-week prime-boost interval, as they look for the optimal approach to roll out, and reassures us that people are protected 22 days after a single dose of the vaccine.”

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