The rollout of the AstraZeneca COVID-19 vaccine that was
supposed to start in South Africa this month, has been placed on temporary
hold, Health Minister, Dr Zweli Mkhize announced during a media briefing last
night (Sunday).
The briefing came promptly after new studies earlier this
week showed that the Oxford/AstraZeneca vaccine, of which South Africa had
procured one million doses from the Serum Institute of India, may not have the
same effectiveness against the mutated COVID-19 501Y.V2 variant – which is
predominant in South Africa.
Mkhize, who was joined by a panel of health experts, confirmed
during the briefing that this particular vaccine is indeed not as effective
against the new coronavirus variant in the country.
According to Professor Shabir Madhi, who led the clinical
trial of the Oxford/AstraZeneca vaccine candidate locally, they conducted a
study using 2000 participants, aged between 18 and 65 years old.
Up until the end of October last year, before the new
variant began spreading, Madhi said that the vaccine showed “tremendous
potential”. Just fourteen days after taking the first of two jabs, participants
showed a 75% lesser likelihood of becoming infected with COVID-19.
“However, the 501Y.V2 variant then emerged and spread
rapidly throughout the country. The study then changed to examine the vaccine’s
potency against the original virus as compared to the new strain. Much of the
antibody induced by the vaccine was not actually active against the variant
circulating in South Africa,” Madhi explained.
“The study 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 added.
“However, COVID vaccines really remain the only sustainable
option of reducing risk of severe disease and death,” he concluded.
According to Professor Salim Abdool Karim, one of South
Africa’s leading COVID-19 experts, 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 added that the Sinopharm vaccine also shows a small
reduction in efficacy, about 1.5-fold.
However also mentioned 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.
“COVID vaccines remain effective against existing variants.
The next set of vaccines will be made from the 501Y.V2 variant, 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 variant and then take this booster in order to
give you protection from the 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.
“The AstraZeneca rollout needs to be put on temporary hold
while we wait to get the clinical efficacy information.”
Source: National Department of Health statement
