AstraZeneca Vaccine Falls Short Against South Africa Variant

AstraZeneca Vaccine Falls Short Against South Africa Variant

A group of South African-based researchers known as the NGS-SA Groups Wits (VIDA COVID Group) recently investigated the safety and efficacy of vaccines against COVID-19 in the context of the emerging variants, including B.1.351 (501Y.V2) first identified in South Africa. Conducting a multicenter, double-blind, randomized controlled trial to investigate the safety and efficacy of ChAdOx1 nCoV-19 vaccine (AZD1222 or the AstraZeneca vaccine) in South Africa the team concluded that a two-dose regimen of the AstraZeneca vaccine failed to protect against mild-to-moderate COVID-19 due to the B.1.351 (South African) variant.

The Study

This study was a Phase 1/2 trial assessing the safety, immunogenicity and efficacy of what is known as the AstraZeneca or “Oxford” vaccine in adults aged 18-65 years old living without HIV in South Africa. The study was led by University of Oxford with co-sponsors, including Medical Research Council (South Africa), Bill and Melinda Gates Foundation, Wits Health Consortium (Pty) Ltd and University of Witwatersrand in South Africa.

Trial Site Locations

This study was conducted across South Africa at locations including Johannesburg (PHRU Kliptown, Soweto Clinical Trials Center), Soshanguve (Setshaba Research Centre) and Cape Town (FAMCRU and Groote Schuur Hospital).


After enrolling 2,026 HIV-negative adults with a median age of 30, 1010 and 1011 participants received at least one dose of placebo or Oxford vaccine product respectively. In the final analysis, the investigators determine that the AstraZeneca vaccine originally developed at Oxford  failed to protect against mild-to-moderate COVID-19 due to the South African variant of the SARS-CoV-2 pathogen. Note that the vaccine still potentially has utility to protect against severe COVID-19.

Call to Action: Read the published study in the New England Journal of Medicine here


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