South Africa has put a temporary halt to the rollout of the Oxford AstraZeneca vaccines, after it was found that the vaccine may not have the same efficacy (or effectiveness) against the mutated COVID-19 501Y.V2 variant, which is predominant in South Africa (and has been blamed for the sharp spike in Coronavirus cases during the second wave).
Just last Monday the country celebrated the arrival of one million doses from the Serum Institute of India, and the rollout was due to begin in a week’s time.
Yesterday, at a media briefing held by Health Minister Dr Zweli Mkhize and a panel of experts, it emerged that a study has shown the vaccine is not active against the variant in SA.
Professor Shabir Madhi – who led the clinical trial of the Oxford/AstraZeneca vaccine candidate locally – said the study was conducted using 2,000 participants, aged between 18 and 65 years old, and that it had shown “tremendous potential” up until the end of October last year (when the new variant began spreading).
Prof Madhi said just 14 days after taking the first of two jabs, participants showed 75% less likelihood of becoming infected with COVID-19.
However, after the emergence and rapid spread in SA of the 501Y.V2 variant – which was first identified in Nelson Mandela Bay – the study then changed to examine the vaccine’s potency against the original virus as compared to the new strain.
It was then found that “much of the antibody induced by the vaccine was not actually active against the variant circulating in SA”.
The study unfortunately showed 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 variant, there was very little difference between the vaccine group and placebo group,” Madhi said.
Vaccines remain best option
“However COVID vaccines really remain the only sustainable option of reducing risk of severe disease and death.”
According to one of SA’s leading Covid-19 experts, Professor Salim Abdool Karim, these findings do not spell “doom and gloom”.
Karim said that vaccines made by Pfizer and Moderna seem to do “reasonably well” against the 501Y.V2 variant, even with their neutralising activity diminished. He said the Sinopharm vaccine also shows a small reduction in efficacy, about 1.5 fold.
However, he says, there is hope that the Johnson&Johnson vaccine will show a smaller decline in efficacy against the variant, making it a plausible choice for rollout.
Vaccine boosters against the 501Y.V2 Variant
“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. We are expecting two kinds of vaccines: the first are 501Y.V2 boosters and we have already heard about the good progress they are making on these boosters,” he said.
“You will take the existing vaccine to give you immunity against the existing variants and then take this booster which will boost it in order to give you protection from 501Y.V2 variant. A 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 says the rollout of the AstraZeneca vaccines which have already landed will need to be put on a temporary hold.
“We can still proceed with our rollout but we need to do it wisely by taking a stepped approach,” he said.
Premier Alan Winde to meet with SAHPRA
Western Cape Premier, Alan Winde, said on Monday morning that he has a key meeting this week with SAHPRA, SA’s regulatory body around medicines, to discuss SA’s vaccines. Premier Winde said: “I think after the weekend’s announcements, some interesting questions will be posed on vaccines, new vaccines, and trials of vaccines and other medical interventions specifically to help us flatten the curve and manage Covid-19 going forward.”
Covid-19 cases in South Africa and the UK
As of Sunday, the total number of confirmed #COVID19 cases in South Africa was 1 476 135 , the total number of deaths 46 290 and the total number of recoveries 1 360 204, said Dr Mkhize.
Meanwhile in England, over 11 million people have already been vaccinated. The country has experienced one of the worst outbreaks of Covid-19, driven by a separate contagious variant found in the UK. England has also been on high alert for the variant identified in South Africa. Last week residents in eight areas were told to stay home to curb the spread of the variant which has been found in at least 100 patients. Over 112,000 people have died in Great Britain from Covid-19 related conditions.
Sources: Dr Mkhize, SACoronavirus.co.za