Of the approximately 200 vaccines being developed to protect against Covid-19, about five have been the leading contenders to have received authorization for use around the world. South Africa received 1 million doses of the AstraZeneca vaccine which was produced in collaboration with Oxford University in the UK, and in which South Africans participated in clinical trials.
Early morning media reports on Sunday were speculating that vaccination could begin in South Africa as early as Wednesday this week. However by the afternoon things had changed. A report by Mark Heywood in the Daily Maverick has outlined two major snags that have just occurred which have put the use of this particular vaccine for South Africans in doubt.
When the vaccines against Covid-19 were being developed in 2020 there were no documented cases of major variations or lineages of the virus occurring. It was only in early 2021 that the UK, South Africa and then Brazil started documenting specific variants from the original.
The two main questions that arose from the identification of the variants were, whether they would cause more severe illness and whether they would be able to resist the vaccines that were being developed.
In the case of the 501Y.V2 variant that was identified in South Africa by Krisp at the UKZN it has been established through scientific studies that it does not cause more severe illness and does not affect young people more than the original Covid-19 virus.
Unfortunately the results of trials of the AstraZeneca vaccine in South Africa show that it is significantly less successful in preventing illness with the new variant than it is with the original. The full details of this vaccine trial are to be released tomorrow but excerpts were published on Saturday night by the Financial Times in London.
Professor Shabir Madhi who led the trials in South Africa told Daily Maverick, "the results from this study are disappointing in this vaccine not protecting against mainly mild and some moderate illness."
It seems that while the AstraZeneca vaccine is safe to use, it has not been proven to prevent mild or moderate illness from Covid-19.
AstraZeneca told the Financial Times that, "We do believe our 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." The problem is that this has not been proven with scientific studies.
Some of the other vaccines being developed have proven in clinical trials that they are still effective at preventing severe disease against the Y501.V2 variant. It may also be possible for vaccines to be adjusted to improve their effectiveness against variants - although this will obviously cause a delay.
Vaccine Expiry Date
A second problem with the vaccine shipment was identified by South African inspectors after receiving the stock this week. The 1 million doses landed at OR Tambo on the 1st of February but have an expiry date in April.
This is a very short timeframe as the vaccine should be given in a two-shot dose which preferably will be 8 to 12 weeks apart. This could lead to some of the vaccines expiring before they can be used.
The South African Ministry of Health will be holding a media briefing on Sunday night at 7pm to give an update on the situation.