In Brief: AstraZeneca vaccine's minimal efficacy against COVID-19 variant in South Africa

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A vial of the Oxford-AstraZeneca COVID-19 vaccine. Photo by: Peter Cziborra / Reuters

South Africa is putting on hold its rollout of the AstraZeneca-Oxford vaccine after new data involving over 1,700 participants showed it has only 22% efficacy against the new coronavirus variant B.1.351, also known as 501Y.V2, currently dominant in the country.

This is a significant drop from the 75% reported efficacy of the vaccine in reducing mild to moderate COVID-19 before B.1.351 became the dominant variant in South Africa.

The latest findings follow interim data from Johnson & Johnson and Novavax released last month, which also showed their vaccines’ reduced efficacy against the B.1.351 variant.

What is the caveat: The latest efficacy data is only for mild-to-moderate COVID-19 infection involving the B.1.351 coronavirus variant. The data was not assessed for severe forms of the disease. Some experts are also saying the study, still in pre-print, is too small to make a definitive conclusion.

Why it matters: Having vaccines that have limited efficacy against the B.1.351 COVID-19 variant — which has been reported in 32 countries and territories — can create additional constraints in efforts to control and bring an end to the pandemic. The latest findings also raise questions regarding the rollout of the AstraZeneca-Oxford vaccine via COVAX, the global COVID-19 vaccine initiative many low- and middle-income countries are relying on. Projected vaccine allocations under COVAX released last week showed the majority will receive the AstraZeneca-Oxford vaccine.

What next: The University of Oxford and partners are already working to produce a second generation of the vaccine that would target COVID-19 variants similar to B.1.351 that can act as boosters.

About the author

  • Jenny Lei Ravelo

    Jenny Lei Ravelo is a Devex Senior Reporter based in Manila. She covers global health, with a particular focus on the World Health Organization, and other development and humanitarian aid trends in Asia Pacific. Prior to Devex, she wrote for ABS-CBN, one of the largest broadcasting networks in the Philippines, and was a copy editor for various international scientific journals. She received her journalism degree from the University of Santo Tomas.