Oxford-AstraZeneca Vaccine Minimally Effective against South African Variant

Fresh vaccine trial results from a study being carried out by Wits University, Johannesburg, were announced on Monday. Unfortunately, the results were not favourable to the Oxford-AstraZeneca vaccine.

South Africa is currently struggling with the B.1.351 variant of the coronavirus. The country has seen at least 46,000 coronavirus deaths and presently has at least 87,000 active cases.

According to New Scientist, it isn’t clear if the South African variant spreads more quickly. What is clear is that a mutation called E484K allows it to evade antibodies developed from prior SARS-CoV-2 infection.

This mutation now appears to hamper the efficacy of the Oxford-AstraZeneca vaccine. While trial results show the vaccine worked against the original coronavirus non-B.1.351 variants, it does not appear to prevent mild infection or transmission of the new variant.

Shabir Madhi, Professor of Vaccinology at Wits and the study’s chief investigator, points out that the Oxford-AstraZeneca vaccine has reduced incidence of severe Covid-19 caused by the new South African variant. He thus suggests we may need to “shift the focus from the aspirational goal of herd immunity against transmission to the protection of all at risk individuals…against severe disease.”

University of the Witwatersrand, Johannesburg.

Echoing this sentiment, Andrew Pollard of the Oxford Vaccine Group said, “Vaccines may continue to ease the toll on health care systems by preventing severe disease.”

The possibility is underlined by the recent detection of the E484K mutation in the UK coronavirus variant, which is known for its fast rate of transmission. This could very well mean that much of the UK variant of the virus, recently detected in Perth, is not constrained by the Oxford-AstraZeneca vaccine, which has been Australia’s central hope for achieving herd immunity.

The study findings are also of great concern for the African continent as a whole. The cheaper and more easily distributed AstraZeneca vaccine had been slated for vaccination programs in Africa.

On the other hand, while the virus is evolving as it spreads from person to person, vaccine developers are also hurrying to collect data and adapt. Moderna is working on a booster shot to enhance protection against SARS-CoV-2 with the E484K mutation, and other manufacturers are looking into what are being called “second generation” vaccines.

Let’s hope the researchers can win this race.

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