Covid variants and vaccine resistance: all you need to know | World news


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.

Pfizer/BioNTech

Country US/Germany

Efficacy 95% a week after the second shot. Pfizer says it is only 52% after the first dose but the UK’s Joint Committee on Vaccination and Immunisation (JCVI) says this may rise to 90% after 21 days.

The UK has ordered 40m doses and is rolling them out now

Doses Clinical trials involved two doses 21 days apart. The UK is stretching this to 12 weeks.

Oxford/AstraZeneca

Country UK

Efficacy 70.4% 14 days after receiving the second dose. May have up to 90% efficacy when given as a half dose followed by a full dose. No severe disease or hospitalisations in anyone who received the vaccine. 

The UK has ordered 100m doses and has begun distribution

Doses Two, four to 12 weeks apart

Moderna

Country US

Efficacy Phase 3 trial results suggest an rating of 94.1%.

The UK has ordered 17m doses, to be delivered in March or April

Doses Two, 28 days apart

Novavax

Country US

Efficacy Phase 3 trials suggest 89.3%.

60m doses ordered by the UK, with distribution expected principally in the second half of the year

Doses Two

Janssen (part of Johnson & Johnson)

Country US

Efficacy 72% in preventing mild to moderate cases in US trials but 66% efficacy observed in international trials. 85% efficacy against severe illness, and 100% protection against hospitalisation and death.

30m doses ordered by the UK

Doses: One, making it unique among Covid vaccines with phase 3 results so far


Photograph: Stéphane Mahé/X02520

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.



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