AstraZeneca Covid-19 Vaccine Shows Lower Efficacy Against South African Variant Of The Virus

Only limited protection against mild disease caused by the South African variant of the novel coronavirus was exhibited by the Cvoid-19 vaccine developed by AstraZeneca and the University of Oxford, said a spokesman for the British drug maker.

This statement from the firm was issued following a report published in the Financial Times where it was claimed that even mild and moderate disease caused by the variant first identified in South Africa was not being able to be prevented by the vaccine.

The report was based on early data from a trial that was conducted by South Africa’s University of the Witwatersrand and the University of Oxford and the findings of that study is yet to be made public.

The trial was conducted among more than 2,000 mainly healthy and young participants and none of the participants died or had to be hospitalised, noted the news report published by the FT. The findings of the study are yet to be peer-reviewed.

“In this small phase I/II trial, early data has shown limited efficacy against mild disease primarily due to the B.1.351 South African variant. However, we have not been able to properly ascertain its effect against severe disease and hospitalisation given that subjects were predominantly young healthy adults,” said an AstraZeneca spokesman  in response to the FT report.

The company however believed that its Coid-19 vaccine could be effective in prevent a severe case of the disease because of the fact that the neutralising antibody activity was equivalent to that of other Covid-19 vaccines that have showed efficacy against severe form of the disease.

The British pharma company has already began the work to adapt its vaccine against the South African variant and “will advance rapidly through clinical development so that it is ready for Autumn delivery should it be needed”, the company spokesman also said.

According to the British Medical Journal, even though with the coronavirus mutating into new variants has resulted in thousands of individual changes rising in it, there was only tiny minority of the changes are important and can potentially bring in any significant changes in the manner in which the virus acts and reacts.

The so-called “South African”, “British” and “Brazilian” variants, which are apparently able to spread more swiftly than others are the ones that have got scientists and public health experts a bit worried among the coronavirus variants that have been currently identified.

Other Covid-19 vaccine makers including scientists and public health experts have also announced that their vaccine showed some reduction in their efficacy as found in trials that were conducted in South Africa.

While an efficacy rate of 57 per cent was exhibited by the Johnson & Johnson vaccine in South Africa compared to the 72 per cent rate of efficacy in the United States and 66 per cent in Latin America, the vaccine from Novax was announced to be 89.3 per cent effective in a trial conducted in the United Kingdom but was found to be only 50 per cent effective in a trial carried out in South Africa.

Moderna also reported a reduced immune response from its vaccine against the South African variant, and has said it will test a new booster shot aimed at that variant.

(Adapted from


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