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Amid Doubts About AstraZeneca Shot, South Africa Denies Wanting To Return Doses

Amid Doubts About AstraZeneca Shot, South Africa Denies Wanting To Return Doses

A health official draws a dose of AstraZeneca’s COVID-19 vaccine candidate made by the Serum Institute of India, at a hospital in Sri Lanka, January 2021. Photo: Reuters/Dinuka Liyanawatte/File Photo.

New Delhi: A senior member of South Africa’s Department of Health denied a report by The Economic Times that the country had asked Serum Institute of India to take back one million COVID-19 vaccine doses the company had sent in early February.

Serum Institute of India, which is producing AstraZeneca’s shot, has emerged as a key vaccine supplier. One million doses of the COVID-19 vaccine landed in South Africa a few weeks ago and another 500,000 were due by April.

The South African government had paused the vaccine rollout following a small clinical trial showed it offered minimal protection against mild to moderate illness from the B.1.351 coronavirus variant dominant in the country.

AstraZeneca has said its vaccine appeared to offer only limited protection against mild disease caused by the variant, based on data from a study by South Africa’s University of the Witwatersrand and Oxford University.

Researchers enrolled 2,026 HIV-uninfected adults between June 24 and November 9, 2020, with 1,010 receiving a placebo and 1,011 the vaccine. The primary endpoint was vaccine safety and efficacy at least 14 days after receiving both doses.

They reported an overall efficacy of 21.9% and 10.4% against mild to moderate COVID-19 infections caused by the new variant, dubbed B.1.351 (42 cases). The team didn’t test the vaccine’s safety or efficacy against severe COVID-19 infections.

The study’s lead author Shabir Madhi told the Wall Street Journal that their data is “too limited to be statistically significant”. Other independent scientists also agreed with this assessment.

But Madhi also said in a statement that the data was still “a reality check” and that “we must recalibrate our expectations”.

Based on the results, South Africa announced it would temporarily suspend distribution of the AstraZeneca vaccine in the country.

AstraZeneca has licensed Serum Institute of India to manufacture the vaccine for India’s COVID-19 vaccination programme – where it will be one of two candidates to be distributed to 300 million frontline and healthcare workers by July 2021.

The vaccine has been embroiled in trouble with regulators in the US, the UK and the EU – in all cases over its underlying data, based on which AstraZeneca has made many controversial claims.

Switzerland has refused to distribute AstraZeneca’s vaccine candidate without clinical trials to check whether the vaccine’s efficacy changes if the first of its two doses is halved in volume or if the two doses are separated by three months.

These questions are the result of a mistake in the vaccine’s phase 3 trials and of questions raised by members of the UK’s Medicine and Healthcare products Regulatory Agency.

European Medicines Agency, which regulates drugs in the EU, has also raised disputes about AstraZeneca not supplying enough doses and over concerns about efficacy among people aged 65 years or older.

The vaccine’s phase 3 clinical trials didn’t include enough people of this age group nor did this group have enough COVID-19 cases to allow for a statistically meaningful estimate of efficacy to be calculated.

But AstraZeneca has said that in the absence of this data, regulators could still consider the vaccine based on its proven immunogenicity (ability to trigger an immune response).

This is similar to what Bharat Biotech has been saying in India, after India’s drug regulator controversially approved its Covaxin candidate with only immunogenicity data and no data from phase 3 trials.

“On this count, both are practically making the same argument,” Dr Srinath Reddy, director of the Public Health Foundation of India, told The Wire Science.

More recently, there was controversy about AstraZeneca’s claims about the vaccine’s effect on transmissibility.

During animal trials, researchers had found that swabs of chimpanzees inoculated with the vaccine contained viral particles. Their presence on nasal swabs meant the individual could still transmit the virus to their surroundings. But researchers said it was possible that they were ‘dead’ particles.

Then the British press reported that according to a preprint paper uploaded on February 1, 2021, the AstraZeneca vaccine candidate could reduce transmission among its recipients.

“The question of whether COVID-19 vaccines reduce transmission has been a critical and unanswered one, creating uncertainty over whether people who have been vaccinated will still be able to be infected by and transmit onward SARS-CoV-2 … to those who have not yet been vaccinated,” Helen Branswell and Matthew Herper wrote for STAT.

The problem was that the paper didn’t prove this claim. Branswell and Herper continued, “What they found was that while a single dose of the two-dose vaccine cut positive test results by 67% – the figure many media reports seized on – two doses reduced the positive tests by a lesser amount, 49.5%.”

This conclusion is more problematic. Neither the paper’s authors nor AstraZeneca have explained it.

Taken together, “AstraZeneca researchers as well as the company have stepped out of the crease too many times – many of them in unorthodox ways – to hit the ball to the boundary,” Dr Reddy said.

AstraZeneca has already announced it will conduct a new trial to test a version of its vaccine against COVID-19 infections caused by the B.1.351 variant.

Now, in addition to a denial by Anban Pillay, the deputy director-general of the health department, that South Africa had asked Serum Institute to take its vaccine doses back, the health minister has said the government may sell the doses as well.

The African country, which is yet to launch its COVID-19 vaccination programme, has decided to start vaccinating health workers with Johnson & Johnson’s vaccine in the form of an “implementation study” with researchers.

The Economic Times report came as the WHO listed the AstraZeneca/Oxford COVID-19 vaccine for emergency use on February 15.

Note: This article was first published on February 17 and was republished on February 22, 2021, with details of South Africa’s denial and the studies based on which experts are asking new questions about the AstraZeneca candidate vaccine.

(With Reuters inputs)

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