Cookies on this website
We use cookies to ensure that we give you the best experience on our website. If you click 'Continue' we'll assume that you are happy to receive all cookies and you won't see this message again. Click 'Find out more' for information on how to change your cookie settings.

Our partners AstraZeneca have today announced the high-level results from the primary analysis of their Phase III trial of the ChAdOx1 nCoV-19 coronavirus vaccine in the US. They confirm that the vaccine efficacy is consistent with the interim analysis results announced on Monday 22 March 2021.

Example vaccine vial in clinic © John Cairns
  • Primary analysis, part of pre-specified trial protocol, follows interim analysis on Monday 22 March
  • Data are consistent with interim analysis, and will form submission by AstraZeneca to US FDA
  • Vaccine 76% effective against symptomatic COVID-19, and 100% effective against severe or critical disease and hospitalisation

This primary efficacy analysis included the accrual of 190 symptomatic cases of COVID-19 from the 32,449 trial participants, an additional 49 cases to the previously announced interim analysis.

In addition, results were comparable across age groups, with vaccine efficacy of 85% in adults 65 years and older. A key secondary endpoint, preventing severe or critical disease and hospitalisation, demonstrated 100% efficacy.

Read the full story on the University of Oxford website.

Similar stories

Alternating vaccines trial expands to include two additional vaccines

COVID-19

Researchers running the Com-Cov study, launched in February to investigate alternating doses of the Oxford-AstraZeneca vaccine and the Pfizer vaccine, have today announced that the programme will be extended to include the Moderna and Novavax vaccines in a new study.

UK and EU regulators conclude benefits of vaccination continue to outweigh the risks

COVID-19

Medical regulators in the UK and Europe have announced their conclusions from their reviews of very rare cases of unusual blood clots in people who have received the Oxford-AstraZeneca coronavirus vaccine.

Oxford University researchers release cheap, quick COVID-19 antibody test

COVID-19

The new easy-to-produce test detects coronavirus spike-protein binding antibodies in people who have tested positive for COVID-19.

USA, Chile and Peru interim trial data show Oxford-AstraZeneca vaccine is safe and highly effective

COVID-19

Oxford-AstraZeneca coronavirus vaccine 79% effective against symptomatic COVID-19 overall. Vaccine 100% effective against severe or critical symptomatic COVID-19. No safety concerns reported

COVID-19: how to tackle vaccine hesitancy among BAME groups

COVID-19 Public Engagement

Samantha Vanderslott, Andrew Pollard and Seilesh Kadambari discuss vaccine uptake among Black, Asian and minority ethnic communities in an article for The Conversation.

Coronavirus vaccination linked to substantial reduction in hospitalisation, real-world data suggests

COVID-19

The first study to describe the effects in real-world communities of the Oxford coronavirus vaccine has been reported in a pre-print publication today, showing a clear reduction in the risk of hospitalisation from COVID-19 amongst those who have received the vaccine.