As countries around the world roll out and accelerate their vaccination programmes and early evidence emerges of their real-life effects, attention is turning to how these programmes will be affected by the global spread of new and potentially more dangerous variants of Covid-19.
The new South African strain in particular is causing difficulties for countries in the developing world, which are having to rethink their procurement and delivery strategies to deal with the mutations.
The AstraZeneca vaccine, which offers reduced protection against mild to moderate illness from the South African variant, accounts for more than a quarter of vaccine procurement in countries where the strain has been detected.
However, in some countries, that figure is as high as 75 per cent. Many of these countries were already being left behind in the race to vaccinate; now they have purchased thousands of jabs that may be less effective.
How do the vaccines interact with the new variants?
So far, evidence shows that the AstraZeneca, Pfizer and Moderna vaccines are effective against the UK strain of Covid-19. Studies of the Brazilian variant are underway. The variant that so far seems more resistant to vaccination appears to be B.1.351, which emerged in South Africa.
A new report published in the New England Journal of Medicine on 17 February found that the Pfizer vaccine can still protect people against the new South African variant of coronavirus, but that its neutralisation of this variant was weaker than that of the “original” virus by approximately two thirds. Moderna has similarly warned that laboratory tests found the antibodies produced by its vaccine were one sixth as effective against the South African variant.
This doesn’t mean a vaccine is ineffective: both trials indicated that the level of antibodies produced was still enough to neutralise the virus to some extent. However, both Pfizer and Moderna have indicated they will update their vaccines in case of evidence that a new strain hinders their efficacy.
Early data suggests the AstraZeneca vaccine is less effective at immunising against mild and moderate infections caused by the South African variant than those caused by the original virus (the head of the Oxford research group told the BBC that the vaccine should still protect against severe disease). The company is working to produce a version of its vaccine that can protect against the variant by autumn 2021, but in the meantime South Africa has stopped the roll-out of this vaccine after a study suggested it did not protect against mild or moderate illness. South Africa is continuing to offer the Pfizer and Janssen (J&J) vaccines (though Janssen has only 57 per cent efficacy against the South Africa variant).
Which countries are most likely to be affected?
South Africa is not the only country with the new strain. You can see exactly where it is spreading using our international coronavirus tracker. Nearly two fifths of the countries with confirmed local transmission of the South African variant are African.
Figures from the Duke University Global Health Innovation Centre show that 77 per cent of the vaccine mix purchased by the African Union (AU) are doses of the AstraZeneca vaccine, and the latest batch was purchased 21 days ago. You can also find data on the different mix of vaccines different countries have purchased using our tracker.
The Africa Centres for Disease Control and Prevention (CDC), part of the AU, has recommended that countries where the new variant isn’t circulating should continue rolling out the AstraZeneca vaccine, but those with the variant should accelerate the introduction of other vaccines. South Africa’s health minister, Zweli Mkhize, said on Tuesday (16 February) that it would offer its unused AstraZeneca jabs to the AU, (though if the new strain continues to spread through the continent, they may be of limited use).
Outside Africa, Bangladesh’s vaccination programme is the most at risk from the South African variant: the only type of vaccine it has ordered to date is AstraZeneca.
However, these figures don’t take the Covax scheme into account. Covax is a World Health Organisation programme that pools international funds to buy vaccines and equally distribute them.
Bangladesh will get 68 million doses of vaccine from the alliance, which has hedged its bets across a wide range of vaccines.
Covax aims to deliver more than two billion vaccine doses by the end of 2021. But at that rate it would take several years to immunise 70 per cent of the world – a rough threshold for herd immunity. During that time, other variants may emerge, for which new vaccines would have to be developed.
The world is caught in a race between vaccines and variants, and while we are making progress towards normality, the situation in Africa demonstrates that we may never eradicate Covid-19 completely.
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