“South Africa switches to J&J’s ‘silver bullet’ as AstraZeneca vaccine falters against local variant of coronavirus”, Daily Maverick
By Estelle Ellis, Johannesburg, 8 February 2021
The roll-out of the AstraZeneca vaccine to South Africa’s health workers has been temporarily halted following results showing low efficacy against the South African variant of the coronavirus.
South African health workers will now receive the Johnson & Johnson single dose vaccine or the Pfizer vaccine, after the Health Minister, Dr Zweli Mkhize, on Sunday 7 February announced a major shift in the country’s vaccine roll-out.
The shift was necessitated by the publication of what the lead investigator in the Oxford/AstraZeneca trial, Professor Shabir Madhi, said were “disappointing results” showing that the vaccine did not work well against the South African variant of the coronavirus.
The South African variant was first identified in November 2020 in cases from Nelson Mandela Bay. At present, more than 90% of positive cases of coronavirus infections in SA are caused by this variant that has been proven to be more contagious than the original virus.
As South Africa has already received one million doses of the Oxford/AstraZeneca vaccine with an expiry date in April, the deputy director-general of the Department of Health, Anban Pillay, said they are engaging with the Serum Institute in India to find a solution.
Madhi said the data from the Oxford/AstraZeneca trial showed that the South African variant of the coronavirus exhibited some resistance to antibodies produced by an immune response to infection with the original coronavirus, and to vaccines.
He said their study involved 2,000 adults between the ages of 18 and 65 without underlying comorbidities. “To be successful we needed to show 60% efficacy.”
He said the study was not designed to test whether the vaccine will protect against severe Covid-19.
Madhi said initial results when the original coronavirus was still the dominant strain in South Africa were very promising and showed high levels of protection – with the vaccine lowering the likelihood of becoming infected with the original virus by up to 75%.
“It showed tremendous potential to prevent infection, mild and moderate disease,” Madhi said
He explained that the new variant of the virus had a different spike protein and the vaccines that had been developed used the spike protein of the original virus to trigger an immune response, leading to diminished efficacy.
“Unfortunately, viruses mutate. Sometimes this is by accident. But often the reason is that the virus wants to become more adept to infect the host.”
This, Madhi explained, was what had happened with the South African variant as well as another variant that was first identified in the United Kingdom.
“In a country like South Africa where as many as 30% of the population were infected during the first wave the virus was under pressure. It had to evolve to ensure its survival,” Mahdi said. “It is a way to become evasive to immune responses.”
He said this held important implications for the future. “This virus is likely to be with us for the course of our lifetimes. It is unlikely that it will be eradicated soon.”
Madhi explained that when they tested the vaccine in the laboratory against the South African variant they realised that the antibodies produced by the Oxford/AstraZeneca vaccine were not active against it.
“That would be reason enough to be concerned that the vaccine did not do what we set out to achieve,” he said.
He added that in clinical trials the vaccine had shown only a 22% lower risk of Covid-19 in the vaccinated group, but added that the data did not indicate whether the vaccine could protect against severe disease and death.
Madhi said that the other clinical trial where he is the principal investigator, the Novavax vaccine trial, had shown a 60% efficacy in protecting against mild and moderate infections with the South African variant.
“It is not all doom and gloom… we do have vaccines that work,” he said, before adding that the Oxford/AstraZeneca vaccine does not work against the South African variant of the virus.
Gray said the Johnson & Johnson vaccine had been proven to protect against severe disease and death in cases of infection with the South African variant.
Madhi said the Johnson & Johnson vaccine produces a very similar antibody to the AstraZeneca vaccine and reduced the risk of mild to moderate disease by 57% and severe disease and death by 80%.
“We were highly optimistic at one stage,” Madhi said. “Had the virus not evolved we would have been in a very good space. The results are a reality check. We were euphoric. We must recalibrate our expectations. But we must also appreciate that vaccines are the only sustainable option to reduce severe disease and death.”
Professor Glenda Gray, the president of the Medical Research Council and the principal investigator for the Johnson & Johnson vaccine, explained that their vaccine was similar to those developed for Ebola, the Zika virus and for some of the ongoing HIV vaccine trials in South Africa.
Gray said the Johnson & Johnson vaccine had been proven to protect against severe disease and death in cases of infection with the South African variant.
“It is a silver bullet, but it won’t protect against the sniffles,” she said.
She said the new plan is for the Johnson & Johnson vaccine to be rolled out to health workers and further evaluated in the field.
“We can’t wait. We already have good local data,” she said.
She said the vaccine, which is given as a single shot, could be kept in an ordinary bar fridge.
Gray said 33% of the subjects in the trial, conducted in several regions around the world, were older than 65 and included patients with comorbidities.
Their trial was carried out at a time when new variants of the virus were emerging and it had shown efficacy against these.
“Johnson & Johnson applied for the emergency use of the vaccine last week. There is a rolling submission before the South African Health Products Regulatory Authority, with data constantly being added.”
She said they are in advanced discussions to roll it out to health workers as an expansion of their study.
Mkhize said this does not mean that health workers will be used as guinea pigs for the vaccine.
“The Johnson & Johnson vaccine has proven to be effective. We are doing an implementation study. Everyone will be vaccinated and then we will monitor what happens,” he said.
“A single shot can stop hospitalisation and death. We want to protect our healthcare workers. The quickest way to bring this vaccine out is to use this programme.”
Mkhize said he has asked a group of scientists to tell the government what to do with the million doses of the AstraZeneca vaccine that arrived in the country on February 2.
“There are no plans to send it back.”
Madhi said studies to look into using a combination of vaccines like the Oxford/AstraZeneca and Pfizer vaccines are ongoing in the United Kingdom.
“It might well be that in South Africa we will explore combining the Johnson & Johnson and the Oxford/AstraZeneca vaccines,” he added.
Madhi stressed that if there is any evidence that the Oxford/AstraZeneca vaccine will protect against severe disease and death it should be rolled out.
“Do we want to take the risk of not vaccinating high-risk populations because we are unsure if it will protect against severe disease? It will be reckless to discard the million doses with the probability that they can protect against severe disease,” he said.
The co-chairperson of the Ministerial Advisory Committee on Covid-19, Professor Salim Abdool Karim, said in the near future there will be a next generation of vaccines that protect against variants of the coronavirus like the South African variant.
“The AstraZeneca roll-out will be put on hold. We are going to roll out [the Johnson & Johnson vaccine] to a fairly large number of people to assess hospitalisation rates. We can do that because we have a system in place,” he said.
Professor Barry Schoub, the chairperson of the Ministerial Advisory Committee on Vaccines, said the country will have to decide what it wants from a vaccine.
“The primary goal is to prevent severe disease, mortality and hospitalisations. That must be our prime aim. We also want to prevent moderate disease as it does have an impact on the economy. We also want to prevent asymptomatic infections as this causes community infections.
“In the short term, the AstraZeneca vaccine had disappointing results – but we may be able to still use it, maybe in combination with other vaccines. We just need to suspend use of AstraZeneca but investigate to see if we can use it in a different way.”
Mkhize said he wanted more work done to see if the Oxford/AstraZeneca vaccine can prevent severe disease and death.
He said the Oxford/AstraZeneca vaccine was ordered before the results were published.
“We will wait for the scientists to come tell us. They must figure it out. But we will hold on to the vaccines for now. We will link the vaccine programme with an implementation study for Johnson & Johnson.”
He said South Africa was also in negotiations to acquire the Russian Sputnik vaccine, the Chinese Sinopharm vaccine, the US Moderna vaccine and will explore acquiring the Novavax vaccine. DM/MC
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