Apprehension rises after SA halts Oxford-AstraZeneca vax rollout, WHO expert look into efficacy

The emergence of new variants of the COVID-19 virus has raised concerns about their potential impacts on the efficacy of vaccines.

By: Jahnavi Sarma | | Updated: February 10, 2021 11:41 am

In India, the Oxford-AstraZeneca vaccine is being rolled out under the name of Covishield.

In recent days, we have seen some amount of confusion regarding the efficacy of the AstraZeneca vaccine against COVID-19. In India, this vaccine is being rolled out under the name of Covishield. This is one of the two approved vaccines and the one that is seen as the first choice by many. So new developments regarding this vaccine are bound to worry a lot of people here. Also Read - Just one shot of Pfizer or AstraZeneca vaccine offers over 90% protection against COVID-19

World Health Organization (WHO) experts came together to review the efficacy of the Oxford-AstraZeneca COVID-19 vaccine, after a study showed that it was less effective against a new variant of the virus discovered in South Africa. At a press briefing in Geneva on Monday, WHO Director-General Tedros Adhanom Ghebreyesus said although the Oxford-AstraZeneca vaccine is one of the several that have been shown to be effective in preventing severe disease, hospitalisations and deaths from COVID-19, the emergence of new variants of the virus has raised concerns about their potential impacts on the efficacy of vaccines, reports Xinhua news agency. He announced that the WHO Strategic Advisory Group of Experts on Immunization (SAGE) met to review the Oxford-AstraZeneca vaccine and discuss these new developments. Tedros added that he will meet with the SAGE Chair on Tuesday to discuss its recommendations. Also Read - COVID-19 vaccine: Complete list of private hospitals where you can get the jab

No protection against mild to moderate infection, says SA study

This came at the heels of a study at the University of Witwatersrand, Johannesburg, which says that the AstraZeneca vaccine “provides minimal protection against mild-moderate COVID-19 infection” from the South African variant. A two-dose regimen of (the vaccine) did not show protection against mild-moderate COVID-19 due to (the South African variant),” the study indicated, adding that efficacy against severe COVID-19, hospitalisations, and deaths was not yet determined. The study, however, did not assess whether the vaccine helped prevent severe COVID-19 because it involved mostly young adults, not considered to be at high risk. Also Read - COVID-19 vaccination for above 45: Full list of comorbidities that can make you eligible

In response, AstraZeneca said it had not been able to properly ascertain the effect of the vaccine on severe disease and hospitalisation caused by the South African variant in the study, given most of the participants were young, healthy adults. But a statement said that the vaccine could protect against severe disease, as neutralising antibody activity is equivalent to that of other COVID-19 vaccines that have demonstrated activity against more severe disease, particularly when the dosing interval is optimised to 8-12 weeks.

South Africa halts AstraZeneca vax rollout in country

Monday’s development came a day after South Africa, where the new variant named B.1.351 was found, announced that the rollout of the AstraZeneca vaccine in the country would be temporarily put on hold until more clinical efficacy information becomes available. Also at the briefing, Kate O’Brien, director of the Department for Immunization, Vaccines, and Biologicals at the WHO, said SAGE had met investigators from the trials being conducted in Britain and Brazil, as well as AstraZeneca and investigators from South African trials.

Vax efficacy dependent on many factors

In looking at evidence on the AstraZeneca vaccine across a number of trials, it is very clear that it has efficacy against severe disease, hospitalisations and deaths among different variants, said O’Brien, while admitting that there are some indications of reduction in the efficacy, some more some less, depending on which variant, which population, and also the neutralizing antibody responses. But there also exists evidence that there is the likelihood that the retention of meaningful impact against severe disease is a very plausible scenario for the product against the B.1.351 variant. O’Brien also noted that “we really have to sort of sail a steady ship, based on the preponderance of evidence and not lurch from one particular report or another report”.

But COVAX to go ahead with distribution

Meanwhile, GAVI, the global Vaccine Alliance and a major player in the WHO-led COVAX initiative for COVID-19 vaccines, has decided to continue rolling out the AstraZen7ec7a vaccine. According to GAVI CEO Seth Berkley, the AstraZeneca vaccine is efficacious and has been reviewed and approved by a number of stringent regulatory authorities.

(With inputs from IANS)

Published : February 9, 2021 5:07 pm | Updated:February 10, 2021 11:41 am

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