Vaxzevria Highly Effective against Beta/Gamma and Delta Variants

Real-world data has shown the Vaxzevria vaccine (formerly AZD1222), co-developed by AstraZeneca, the University of Oxford and its spin-out company, Vaccitech, is highly effective after one dose against hospitalization or death caused by Beta/Gamma and Delta variants of the SARS-CoV-2 virus.

Vaxzevria shows 82% and 87% effectiveness after one dose against hospitalisation or death caused by Beta/Gamma and Delta variants

The Results from the Canadian Immunization Research Network (CIRN) with support from Public Health Agency of Canada and the Canadian Institutes of Health Research, published as a pre-print, have demonstrated that one dose of Vaxzevria was 82% effective against hospitalisation or death caused by the Beta/Gamma variants. The Vaxzevria vaccine has also displayed a high level of effectiveness against the Delta (B.617.2, ‘Indian’) and Alpha (B.1.1.7, ‘Kent’) variants with an 87% and 90% reduction of hospitalisations or deaths respectively.

The effectiveness of Vaxzevria after only one dose, against hospitalisation or death, was comparable to that of other vaccines tested in the Canada-based study. Follow-up time was not enough to report on the effectiveness of Vaxzevria after two doses, however, other studies have showcased increased effectiveness after the indicated two-dose schedule.

The analysis included 69,533 individuals who tested positive for SARS-CoV-2 during December 2020 to May 2021 in Ontario, Canada; with 28,705 (6.8%) positive for non-variants of concern SARS-CoV-2 and 40,828 (9.7%) positive for a variant of concern.

Mene Pangalos, Executive Vice President, BioPharmaceuticals R&D, said:

“With different variants threatening to disrupt our route out of the pandemic, this real-world evidence shows that Vaxzevria, along with other vaccines used in Canada, provides a high level of protection against the most serious forms of the disease, even after just one shot. It is essential that we continue to protect as many people as possible in all corners of the world in order to get ahead of this deadly virus.”

Vaxzevria was found to be effective against milder symptomatic disease although, given that data was only reported after a first dose instead of the indicated two-dose schedule where efficacy is known to be boosted in this disease setting, the efficacy was lower than against severe disease. The vaccine’s efficacy against any symptomatic disease was 50% against the Beta/Gamma variants, and 70% and 72% against the Delta and Alpha variants, respectively.

A Phase I/II trial conducted in January by the University of Oxford and University of the Witwatersrand had shown limited efficacy against mild disease mainly due to the Beta variant. It was unable to properly ascertain vaccine efficacy against severe disease including hospitalisation and death because the study subjects were primarily healthy young adults who only experienced the mild form of the COVID-19 disease.

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About the Vaxzevria (formerly AZD1222) COVID-19 vaccine

Vaxzevria has been co-invented by the University of Oxford and its spin-out company, Vaccitech. It utilises a replication-deficient chimpanzee viral vector based on a weakened version of a common cold virus (adenovirus) that causes infections in chimpanzees and contains the genetic material of the SARS-CoV-2 virus spike protein. Following vaccination, the surface spike protein is produced, priming the immune system to attack the SARS-CoV-2 virus if it later infects the body.

To date, the vaccine has been granted a conditional marketing authorisation or emergency use in more than 80 countries around the world. In excess of 700 million doses of COVID-19 Vaccine AstraZeneca have been distributed to 170 countries globally, including in more than 100 countries through the COVID-19 Vaccines Global Access (COVAX) Facility.


AstraZeneca (LSE/STO/Nasdaq: AZN) is a global, science-led biopharmaceutical company that focuses on the discovery, development, and commercialisation of prescription medicines in Oncology, Rare Diseases and BioPharmaceuticals, including Cardiovascular, Renal & Metabolism, and Respiratory & Immunology.

Based in Cambridge, UK, AstraZeneca operates in more than 100 countries and its innovative medicines are used by millions of patients worldwide. For more information, please lease visit

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