The Oxford/AstraZeneca vaccine is the mainstay of the UK government’s immunisation plans and vital globally.
Will it work against the variant of the virus that emerged in South Africa?
A study carried out by Oxford and Astra Zeneca together with the University of Witwatersrand in South Africa shows that it does not protect people infected with the variant against mild to moderate Covid, but the researchers believe it will still prevent severe illness, hospitalisation and death.
The study involved more than 2,000 people with an average age of 31, which means they were relatively young and at lower risk. So scientists cannot yet be certain the protection remains against serious disease, but they think it’s likely.
Do other vaccines offer better protection against this variant?
It’s not possible to make comparisons because we don’t have the detailed data – the study will be published in the coming days. But trials of other vaccines in communities affected by this variant show that none of them work as well as they do against the original coronavirus.
Data that has recently been published, from trials of two vaccines that took place partly in South Africa after the emergence of the variant, show a marked decline in efficacy. Novavax had 89% efficacy in trials in the UK, but 60% in South Africa, where 92% of the cases were caused by the variant. The Janssen vaccine, made by a subsidiary of Johnson & Johnson, had 72% efficacy in the US but 57% in South Africa. Both vaccines, however, still protected against severe disease, hospitalisation and death.
Pfizer/BioNTech and Moderna, which ran large-scale trials with spectacular results showing 95% efficacy before the variants appeared, now think the South Africa variant will reduce that. They have only conducted lab studies, but on the basis of those, they say the vaccine may may perform less well against the variant. We don’t yet know how much less well.
What about the variant that emerged in Kent?
There’s better news about this one. Oxford/AstraZeneca have carried out a small study, details of which came out on Friday, with much more upbeat results. In a pre-print, not yet peer-reviewed, they said the vaccine efficacy fell from an average of 84% against the original virus to 75% against the Kent variant.