South Africa has temporarily suspended the rollout of the Oxford-AstraZeneca vaccine after new studies released last week showed that it is less effective against the mutated SARS-CoV-2 501Y.V2 variant, which is common in South Africa.
On 1 February, the country received its first shipment of one million Oxford-AstraZeneca vaccine doses out of the 1.5 million procured from the Serum Institute of India (SII).
Last night, Health Minister, Dr Zweli Mkhize and a panel of experts hosted a media briefing to outline new developments in South Africa's COVID-19 vaccine acquisition and rollout programme.
Professor Shabir Madhi, who led the clinical trial of the Oxford-AstraZeneca vaccine candidate locally, said they conducted a study using 2 000 participants, aged between 18 and 65 years.
According to research, the vaccine showed "tremendous potential" before the new variant began spreading.
Madhi said just 14 days after taking the first of two jabs, participants showed a 75% lesser likelihood of becoming infected with COVID-19.
However, things changed slightly when the 501Y.V2 variant, first discovered in November 2020, emerged and spread rapidly throughout the country.
"Much of the antibody induced by the vaccine was not actually active against the variant circulating in South Africa," Madhi explained.
The study has since shown a "substantial drop" in the vaccine's ability to neutralise the activity of the virus when tested in the lab.
"When we analysed individuals in terms of how well the vaccine worked against the 501Y.V2 variant, there was very little difference between the vaccine group and placebo group," Madhi said.
According to the latest data, the Oxford-AstraZeneca vaccine will protect three in four people against variants from the first wave, while it protects one in four people from the new variant in the second wave.
According to one of South Africa's leading COVID-19 experts, Professor Salim Abdool Karim, it is not all doom and gloom.
Karim said vaccines made by Pfizer and Moderna seem to do "reasonably well" against the 501Y.V2 variant, even with their neutralising activity diminished.
He said China's Sinopharm shot also shows a small reduction in efficacy of about 1.5 fold.
However, not all is lost, with the Johnson & Johnson vaccine showing a smaller decline in efficacy against the 501Y.V2 variant, making it a plausible choice for rollout.
"COVID vaccines remain effective against existing variants. The next set of vaccines will be made from the 501Y.V2 variant and so they are likely to be effective against the 501Y.V2 variant," Karim said.
Meanwhile, he said the country is expecting two kinds of vaccines, the 501Y.V2 boosters and the next generation of vaccines.
"You will take the existing vaccine to give you immunity against the existing variants and then take this booster in order to give you protection from the 501Y.V2 variant.
"The next-generation of vaccinations is intended to be much broader and will cover you from the current and future variants. That will take a little longer to develop," Karim said.
Karim said prudence will need to be applied in the rollout of the AstraZeneca vaccine.
"We can still proceed with our rollout but we need to do it wisely by taking a stepped approach (sic)."
Madhi believes that South Africa should also explore the interchangeability of vaccines, possibly using the Johnson & Johnson and Oxford-AstraZeneca together.
"South Africa is very likely to, unfortunately, experience another resurgence in the next two or four months. The question we need to ask ourselves -- in the context of knowing that the COVID-19 vaccines, both the AstraZeneca and Johnson & Johnson are safe, even though there are question marks of the effectiveness of the AstraZeneca vaccine against severe disease -- is do we want to take the risk of not vaccinating high-risk groups, knowing that it may not cause harm and they might be protected against severe disease?"
Madhi said it would be "reckless" to decide to discard all the million doses of the Oxford-AstraZeneca vaccine, which may still be useful in defending against severe disease.
He believes the country may have to "reframe" the target group for vaccination in the next few weeks.
Johnson & Johnson, Pfizer vaccines coming soon
According to Minister Mkhize, the country is expecting Johnson & Johnson and the Pfizer vaccines in the next coming weeks, which will be made available to healthcare workers.
Meanwhile, he said the Oxford-AstraZeneca vaccine will remain until scientists have done further investigations.
President and CEO of the South African Medical Research Council (SAMRC), Professor Glenda Gray, said the Johnson & Johnson vaccine protects against severe disease, hospitalisation and death with the current variant.
"This is a vaccine that is a silver bullet... We have local data now and it will be not good to wait for future vaccines. We have to start with the data that we have," Gray said.
Gray has assured the nation that government is committed to protecting healthcare workers.