'It's not a setback at all': SA to press on with Pfizer Covid-19 vaccine

Experts play down results of new study on vaccine's efficacy

21 February 2021 - 00:01 By ZIMASA MATIWANE, GRAEME HOSKEN and CLAIRE KEETON
Health minister Zweli Mkhize receives his Covid-19 vaccination at Khayelitsha District Hospital in Cape Town this week.
Health minister Zweli Mkhize receives his Covid-19 vaccination at Khayelitsha District Hospital in Cape Town this week.
Image: Esa Alexander

SA is pushing ahead with the planned rollout of the Pfizer vaccine, with experts not overly concerned about the results of a new study showing that the dominant local coronavirus variant may reduce protective antibodies it triggers by two-thirds.

Health minister Zweli Mkhize told the Sunday Times he was "comfortable" the rollout should continue as planned.

"It's not a setback at all. But we will do an implementation study with the first few batches. We will vaccinate the first few and monitor them," Mkhize said.

SA has committed to 20-million doses from Pfizer, and Mkhize revealed the government has ordered more. An announcement will be made once figures are finalised.

Professor Barry Schoub, ministerial advisory committee (MAC) vaccine head, said "too much is being made" of the Pfizer study.

"The efficacy reduction is not that significant. While we do not know its absolute efficacy yet, SA should absolutely be getting this vaccine."

Schoub said a small batch of the Pfizer vaccine was due to arrive within the next few weeks, with the bulk arriving in May.

He said lots of clinical data on several vaccines was still outstanding.

"We have good data from the Johnson & Johnson vaccine and almost [as] good data from Pfizer. We still, however, don't know how effective AstraZeneca is against severe infections, although against mild and moderate symptoms it is only 22% effective."

South African Medical Research Council (SAMRC) president Glenda Gray said the Pfizer vaccine needed to be clinically evaluated in the field to know its true efficacy.

"It is important to establish real life, in vivo, data in clinical trials. In vitro [in laboratory] data is an indication, but we need to know how it works in the field."

Gray said the efficacy of all the proven vaccines had taken a knock against the variant. "I think it is important to go ahead [with Pfizer vaccinations] and there should be a parallel stream, rapidly evaluating the data."

These results could inform whether to rapidly escalate vaccinations with the Pfizer vaccine or not, she said.

On the AstraZeneca vaccine, Gray said scientists had to be careful about extrapolating its efficacy against severe disease.

Mkhize confirmed the government is negotiating with 20 African countries on the possible purchase of its AstraZeneca vaccine stock. SA took receipt of a million doses three weeks ago, shortly before the release of a small study that found AstraZeneca had a 22% efficacy rate against preventing mild and moderate infections from the 501Y.V2 variant. A further 500,000 doses are due this month.

"Some people are saying use them on people with co-morbidities, prioritise health workers and so on. That is all in discussion, we will wait for the MAC to give us a sense of how they would like us to conduct the study, then we will make available the number of vaccines necessary for the study.

"But right now all of it is going to the African continent and they will be distributed in about 20 countries that will use them for their health workers."

Mkhize said another option was to exchange AstraZeneca for other vaccines, through the AU platform. "We are extremely excited with that because we are now in a position to support the rest of the continent. For me it is a win-win, it's good for all of us. We might need to swap them, but we will not lose money."

But some scientists have urged SA to roll out the AstraZeneca vaccine.

Professor Shabir Madhi, the SAMRC's vaccine and infectious diseases analytics unit director, said SA should not sell off its AstraZeneca supplies.

"The results reported from the AstraZeneca study on the South African Covid-19 variant have been completely misread and misinterpreted," Madhi said. "It's the same with the Pfizer vaccine. The results cannot be used in any way to determine whether the vaccine cannot be used to protect against severe disease or not."

He said AstraZeneca was still very likely to protect against severe disease, "which is why WHO [the World Health Organisation] recommended the vaccine be used in countries where new variants are circulating. It does not make sense not to offer the vaccine to high-risk groups when it's available, unless one can guarantee another vaccine will become available in the next few weeks which targets high-risk individuals. At the moment there is no such guarantee."

Madhi said SA needed to recalibrate its vaccine expectations, "especially in the era of new variants".

"First-generation Covid-19 vaccines are no longer the tool required to reach herd immunity in countries with widespread variant circulation. It's highly unlikely we will get 67% of the population vaccinated for herd immunity," he said.

Wits University health economist professor Alex van den Heever said it was crucial that SA's vulnerable population was urgently vaccinated with the AstraZeneca vaccine, "which is approved for rollout".

"There is a high risk that over the next few months millions of vulnerable people will remain unvaccinated. With the 1-million doses already in the country, it would have been logical to administer the vaccine now and follow up with booster jabs when the remaining doses arrive."

Professor Willem Hanekom, African Health Research Institute director, said SA faced major dilemmas in regards to the vaccines, especially AstraZeneca.

"There is a good rationale for us to hold onto vaccines while we work out if we should be giving it away or do more tests. The problem though is its expiry date. That could be driving government to want to share it with other countries not affected by our Covid-19 variant.

"Intense debates are raging in the MAC, SA Health Products Regulatory Authority and among vaccinologists to determine the way forward. I agree with some vaccine experts that it could be likely these vaccines will protect against severe disease. The big question though is the lack of data around the vaccines' efficacy against our variant."

SA Medical Association head Angelique Coetzee said that with the AstraZeneca expiry date of April 16, SA had run out of time for the vaccine. "AstraZeneca has approval for rollout, but its efficacy against severity is questionable. Vaccines cannot be administered where there is no true data indicating whether severe disease can be prevented."


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