South Africa suspends use of AstraZeneca jab in national rollout

By Jane Byrne contact

- Last updated on GMT

GettyImages/Chaz Bharj
GettyImages/Chaz Bharj

Related tags: vaccine efficacy, variant, COVID-19

South Africa is halting the use of the Oxford University-AstraZeneca COVID-19 vaccine in its vaccination campaign following the release of trial data showing the jab offered limited protection against mild to moderate infection caused by the country’s dominant coronavirus variant, B.1.351.

The government had been intending to give the AstraZeneca vaccine to healthcare workers; it received one million doses of the vaccine from the Serum Institute of India last week.

Referencing the trial data, South Africa’s minister for health, Zweli Mkhize, said yesterday [February 7] that the authorities would await advice from scientists on the next steps to take in terms of using the AstraZeneca vaccine - ChAdOx1 nCoV - in the national rollout.

The study

According to the trial, which was undertaken by the researchers based at the University of Witwatersrand, other researchers in South Africa along with experts based at the University of Oxford, UK, viral neutralization by sera induced by the ChAdOx1 nCoV-19 coronavirus vaccine against the B.1.351 coronavirus variant were substantially reduced when compared with the original strain of the coronavirus.

The researchers said these early, preliminary data, which have been submitted for scientific peer-review, appear to confirm the theoretical observation that mutations in COVID-19 seen in South Africa will allow ongoing transmission of the virus in vaccinated populations, as has been recently reported, even in those with prior infection due to earlier circulating variants.

Efficacy against severe COVID-19 infection from this variant was not assessed, they added. 

"In this study of approximately 2,000 volunteers who were, on average, 31 years old, mild disease was defined as at least one symptom of COVID-19. Protection against moderate-severe disease, hospitalisation or death could not be assessed in this study as the target population were at such low risk."

Shabir Madhi, professor of vaccinology and director of the Vaccines and Infectious Diseases Analytics (VIDA) research unit at University of the Witwatersrand, and chief investigator on the trial in South Africa said: “These findings recalibrate thinking about how to approach the pandemic virus and shift the focus from the goal of herd immunity against transmission to the protection of all at risk individuals in population against severe disease.”

Andrew Pollard, professor of pediatric infection and immunity, and chief investigator on the Oxford vaccine trial, said the data confirms that the pandemic coronavirus will find ways to continue to spread in vaccinated populations, as expected. “But, taken with the promising results from other studies in South Africa using a similar viral vector, vaccines may continue to ease the toll on health care systems by preventing severe disease.”

Work has already started at the University of Oxford, in conjunction with partners, to produce a 2nd generation of the vaccine which has been adapted to target variants of the coronavirus with mutations similar to B.1.351.

Sarah Gilbert, professor of vaccinology at the University of Oxford, said efforts are underway to develop a new generation of vaccines that will allow protection to be redirected to emerging variants as booster jabs, if it turns out that it is necessary to do so.

“We are working with AstraZeneca to optimize the pipeline required for a strain change should one become necessary. This is the same issue that is faced by all of the vaccine developers, and we will continue to monitor the emergence of new variants that arise in readiness for a future strain change.”

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