THERE was excitement when the AstraZeneca vaccine from the Serum Institute of India arrived in the country on 1 February.

According to Health Minister Dr Zweli Mkhize, healthcare workers were supposed to get vaccinated on Wednesday, 10 February.

And then came the shocking news on Sunday, 7 February, that the AstraZeneca vaccine was not effective in protecting against mild to moderate illness from the 501.YV2 variant of Covid-19 that was discovered in Mzansi in December 2020.

Why did we buy the vaccine?

The AstraZeneca vaccine had been reported to have an averaging efficacy rate of 70%, making it one of the best vaccines that offered protection against Covid-19.

Analysis of the clinical trials showed that the vaccine was highly effective in providing protection against severe cases of illness and hospitalisation.

Some of the participants in the trials were from South Africa, through a research partnership between Oxford University and the Wits University.

All of this was before the new variant 501.YV2 that has been dominant in Mzansi since its discovery in December.

Mkhize said the country had to act quickly to acquire the vaccine due to fears of being left behind in the global race to secure the highly sought after vaccine.

“In the process, we went for availability, where we looked at which of these vaccines could be accessed as early as possible,” said the minister at a public briefing.

Once scientists realised there was a new variant of the virus in the country. Questions rose on whether the current vaccines would still be effective against it.

Led by Shabir Mahdi, Professor of vaccinology and director of the Vaccines & Infectious Diseases Analytics Research Unit at Wits, 2 000 participants with an average age of 31 years, were involved in a trial to investigate the effectiveness of the AstraZeneca vaccine against mild illness as a result of the new strain.

The results showed that the vaccine does not protect against mild and moderate infection due to the 510Y.V2 variant. However, the study was not designed to address protection against severe disease due to either the original-like virus or the N501.Y.V2 variant. Pooled analysis of data indicate the AZ vaccine has higher efficacy against severe disease than any severity of Covid-19 illness.

“Unfortunately that AstraZeneca vaccine does not work against mild to moderate illness, unlike the Novavax protein-based vaccine which is the only vaccine shown to reduce risk of mild-moderate Covid-19 from the N510Y.V2 variant by 60% in people without HIV,” said Madhi, who was also at the briefing with the minister.

Can Mzansi still use the AstraZeneca vaccine?

Government was still considering various options to salvage the situation, while also ensuring the vaccination plans are not completely derailed.

Mkhize said decisions on what to do with the vaccine relied on advice from experts.

In the meantime, studies have been initiated to look at whether the vaccine could still provide protection against severe illness and hospitalisation in a larger population. Following deliberations by the Scientific Advisory Group of Experts on immunisation (SAGE), the WHO recommended the ongoing rollout of the AZ vaccine even in settings with the N501Y.V2 variant, as the vaccine is likely to reduce risk of severe Covid-19.

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