Scientists tonight sounded the alarm over a new 'worst-ever' super-mutant Covid variant that will make vaccines at least 40 per cent less effective - forcing flights to be banned from South Africa and five other countries.
Experts explained earlier how the B.1.1.529 variant has more than 30 mutations – the most ever recorded in a variant and twice as many as Delta – that suggest it could be more jab-resistant and transmissible than any version before it.
The variant - which could be named 'Nu' by the World Health Organization in the coming days - has caused an 'exponential' rise in infections in South Africa and has already spread to three countries – including Hong Kong and Botswana, where it is believed to have emerged.
In response, Health Secretary Sajid Javid announced that flights from South Africa, Namibia, Lesotho, Botswana, Eswatini and Zimbabwe will be suspended from midday Friday and all six countries will be added to the red list.
Mr Javid said: 'The early indication we have of this variant is it may be more transmissible than the Delta variant and the vaccines that we currently have may be less effective against it.
'Now to be clear, we have not detected any of this new variant in the UK at this point in time. But we've always been clear that we will take action to protect the progress that we have made.
'So what we will be doing is from midday tomorrow we will be suspending all flights from six, southern African countries and we will add in those countries to the travel red list.
'Those countries are South Africa, Namibia, Lesotho, Eswatini, Zimbabwe and Botswana. We will be requiring anyone that arrives from those countries from 4am on Sunday to quarantine in hotels.
'If anyone arrives before then they should self-isolate at home and take a PCR test on day two and day eight. If anyone has arrived from any of those countries over the last 10 days, we would ask them to take PCR tests.'
The minister added: 'Our scientists are deeply concerned about this variant. I'm concerned, of course, that's one of the reasons we have taken this action today.'
This chart shows the proportion of cases that were the B.1.1.529 variant (blue) and Indian 'Delta' variant (red) over time in South Africa. It suggests that the mutant strain could outcompete Delta in the province within weeks
The above slide shows the proportion of tests that picked up a SGTF mutation, a hallmark of the B.1.1.529. It suggests that the Covid variant may be spreading rapidly in the country. The slide was presented at a briefing today run by the South African Government
The above slide shows variants that have been detected by province in South Africa since October last year. It suggests B.1.1.529 is focused in Gauteng province. This was presented at a briefing today from the South African Government
The above shows the test positivity rate — the proportion of tests that picked up the virus — across Gauteng province. It reveals that there is an uptick of cases in the northern part of the province. It is not clear whether this could be driven by B.1.1.529
He said that more work was needed to understand how concerning the variant is, adding: 'From what we do know there's a significant number of mutations, perhaps double the number of mutations that we have seen in the Delta variant.
'That would suggest that it may well be more transmissible and the current vaccines that we have may well be less effective.'
The variant has not yet been given the title 'variant of concern' in the UK, but one senior UK Health Security Agency (UKHSA) expert said: 'This is the worst variant we have seen so far.'
Only 59 confirmed cases have been identified in South Africa, Hong Kong and Botswana.
The variant has over 30 mutations - around twice as many as the Delta variant - which could potentially make it more transmissible and evade the protection given by prior infection or vaccination.
The expert whose modelling helped instigate the first coronavirus lockdown said that the decision to impose travel restrictions was 'prudent'.
Professor Neil Ferguson, a member of the Scientific Advisory Group for Emergencies (Sage), said: 'The B.1.1.529 variant has an unprecedented number of mutations in the spike protein gene, the protein which is the target of most vaccines.
'There is therefore a concern that this variant may have a greater potential to escape prior immunity than previous variants.
'It is also concerning that this variant appears to be driving a rapid increase in case numbers in South
