On Saturday night an article in the UK’s Financial Times leaked results of efficacy trials of the AstraZeneca vaccine on participants in South Africa where the 501Y.V2 variant of SARS-CoV-2 is dominant.

A report on this trial’s outcome was due to be released in South Africa on Monday by the University of the Witwatersrand’s Prof Shabir Madhi, the trial’s principal investigator. 

The Financial Times headlines its story, “Oxford/AstraZeneca jab fails to prevent mild and moderate Covid from South African strain, study shows”. The newspaper claims that in trials: “the jab showed significantly reduced efficacy against the 501Y.V2 viral variant, which is dominant in South Africa, according to the randomised, double-blind study …”

Then, quoting directly from the study: “A two-dose regimen of [the vaccine] did not show protection against mild-moderate Covid-19 due to [the South African variant].”

The Financial Times notes that the study has not yet been peer-reviewed and that the vaccine’s efficacy on severe Covid, hospitalisations and on mortality could not be ascertained because most of the study’s 2,026 participants were healthy HIV negative adults with a median age of 31. 

On this important point, AstraZeneca responded to the FT saying:

“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, particularly when the dosing interval is optimised to eight-12 weeks,” …. Initial data, it said, indicated those responses “may remain intact” against the South African variant.

A senior South African vaccine researcher also confirmed this. 

However, as this has not yet been validated through randomised control trials, a scientific surmise is insufficient to justify commencing use of this vaccine on the general adult population in South Africa – at this point.

It is important to stress that there are no safety issues with the AstraZeneca vaccine; it is safe, the questions are all linked to its efficacy against the 501Y.V2 variant.

On Sunday morning Prof Madhi confirmed that the vaccine had failed against the variant and told Maverick Citizen:

“The results from this study are disappointing in this vaccine not protecting against mainly mild and some moderate illness. In all likelihood, other first generation Covid vaccines are likely to also show diminished efficacy against the B.1.351 variant [commonly known as the SA variant] as was evident for the Novavax study. 

“Also, there are compelling ongoing lab studies that show even the mRNA vaccines will have reduced effectiveness against variants similar to the B.1.351. Nevertheless, based on the findings of the J&J vaccine, which uses the same technology and has similar immunogenicity to the AZ vaccine, this vaccine may still provide protection against severe disease and death – with an 85% efficacy observed for the J&J study. 

“The findings also suggest as a global community, we need to recalibrate our thinking around the pandemic and expectations of Covid vaccines.”

Expiry date

Another issue that is said to have raised concerns is the expiry date on the vaccines South Africa received last week from the Serum Institute (SI).

After their arrival at OR Tambo International Airport on 1 February, the vaccines were taken over by the SA Health Products Regulatory Authority (Sahpra) who are legally required to quality check the batch before they can be used. This process is underway at the National Control Laboratory at the University of the Free State in Bloemfontein. 

However, we have learnt that the Department of Health and Sahpra were concerned to discover that the vaccines have an expiry date in April. Given that the AstraZeneca vaccine requires two shots, spaced several weeks apart, this raised the danger that, unless administered urgently, many of the vaccines would become unusable by April.

Questions about this were sent to the Department of Health, the Serum Institute and Sahpra on Saturday. The Department of Health and Serum Institute failed to respond. A senior official in Sahpra, however, admitted that this “is being discussed between the DOH and the Serum Institute” adding that “the expiry dates are not necessarily cast in stone as manufacturers get more information on this all the time.”

What next?

Anban Pillay, the Deputy Director General in the National Department of Health (NDoH) responsible for Health Regulation and Compliance, indicated that a media briefing with Health Minister Zweli Mkhize would take place on Sunday at 7pm.

At this briefing, the NDoH will respond to what the new findings will mean for the rollout of the vaccines already received, which was due to commence within a week. 

However, it’s clear that there will have to be an urgent reassessment of the existing plans.

Maverick Citizen has learned that as soon as the government was made aware of the preliminary results it went into overdrive to assess their implications and come up with a plan B. It is expected that this will mean expediting access to a vaccine, such as those under development by Johnson and Johnson or Novavax, both of which have recently reported efficacy in preventing severe disease and death, including in SA even in the presence of the 501Y.V2 variant. 

“It’s not the government’s fault,” said one of the scientists we consulted. The researcher said that “a responsible government has to act on the science and be prepared to change trajectory even if it costs money and time. 

“These results, although a setback, in no way alter what science has already shown us about the efficacy and safety of Covid-19 vaccines. The problem is that up until October 2020, most vaccines were being developed in relation to the ‘wild-type’ virus. Vaccinologists and pharmaceutical companies are already working on adaptations to the vaccines to meet the challenges of the mutagenic virus.”

Nonetheless, the immediate implications of these findings for South Africa and the rest of the developing world who have placed orders for billions of doses of the AstraZeneca vaccine are huge. 

The senior researcher described this as a “setback” and a warning that people must appreciate that the road to vaccine rollout is going to be a rocky one, not only in terms of the government’s plans but the science and ability of medicine to control this virus and its present and future mutations. 

“Government is taking this extremely seriously and following the science. We must trust them on this,” she said.

These results emphasise once again the continued importance of non-pharmaceutical interventions as a fail-safe way to slow transmission and mutation. However, because of the cost of economic disruption and the difficulty of following public health recommendations for many people in desperate socio-economic circumstances (where social distancing and hygiene is extremely difficult), vaccines are seen as the indispensable  “silver bullet”. They are vital to helping countries to reach the level of population (“herd”) immunity needed to control Covid-19 effectively and bring to an end its ability to cause severe illness and death in millions of people worldwide. 

Already, as illustrated in this vaccine tracker on the website Our World in Data, millions of doses have been administered in developed countries and are showing a beneficial impact. However, the reliance of developing countries on the AstraZeneca vaccine (336 million doses will be distributed by Covax in its first round of distribution) means that if the 501Y.V2 viral variant becomes dominant in these countries as well (which may already be the case), poor people will be left even further behind.

This makes the bad news about the efficacy of the AstraZeneca vaccine on mild to moderate disease caused by the variant not just a South African issue, but a matter of global concern. It is an issue that will today be facing not just the President and Minister of Health, but the World Health Organisation, Covax and leaders all over the globe. DM/MC

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