Whack-a-mole-style restrictions need to be reintroduced in areas to stop the spread of the South African Covid variant, scientists have warned.
More than 70 people in South London are being forced to self-isolate after catching the mutant strain, which experts fear can partially evade vaccines.
Everyone over the age of 11 who either lives in, works in or travels through Lambeth or Wandsworth is being urged to get swabbed, in the largest surge testing operation to date.
But experts say the increase in testing alone may not be enough to stop the variant’s spread and measures including shutting schools may be needed.
No10’s advisers have warned that Boris Johnson’s lockdown-easing plan may need to be delayed, if the strain takes off.
Professor Rowland Kao, an epidemiologist at the University of Edinburgh and SAGE adviser, told the Guardian imposing local restrictions would ‘be in order’ to contain clusters.
Professor Rowland Kao, an epidemiologist at the University of Edinburgh and member of the Spi-M subgroup of SAGE, has warned local restrictions will be needed on top of surge testing to curb outbreaks of new variants
More than 70 people in Wandsworth and Lambeth are being forced to self-isolate after reportedly contracting the South African variant that could weaken the vaccine
People stand socially distanced as they queue to enter to take a Covid test at a mobile novel coronavirus testing centre in Brockwell Park in south London
He said: ‘Surge testing can work if it is broad enough and intensive. But it needs to be accompanied by good adherence to at least some restrictions and isolation of contacts, in order to avoid having anything like a local lockdown again.
WHY ARE SCIENTISTS SO SCARED OF THE SOUTH AFRICAN VARIANT?
The variant has mutations on its spike protein which scientists fear will make it difficult for the immune system to recognise, even in vaccinated people
Real name: B.1.351
When and where was it discovered?
Scientists first noticed in December 2020 that the variant, named B.1.351, was genetically different in a way that could change how it acts.
It was picked up through random genetic sampling of swabs submitted by people testing positive for the virus, and was first found in Nelson Mandela Bay, around Port Elizabeth.
Using a computer to analyse the genetic code of the virus – which is viewed as a sequence of letters that correspond to thousands of molecules called nucleotides – can help experts to see where the code has changed and how this affects the virus.
What mutations did scientists find?
There are two key mutations on the South African variant that appear to give it an advantage over older versions of the virus – these are called N501Y and E484K.
Both are on the spike protein of the virus, which is a part of its outer shell that it uses to stick to cells inside the body, and which the immune system uses as a target.
They appear to make the virus spread faster and may give it the ability to slip past immune cells that have been made in response to a previous infection or a vaccine.
What does N501Y do?
N501Y changes the spike in a way which makes it better at binding to cells inside the body.
This means the viruses have a higher success rate when trying to enter cells when they get inside the body, meaning that it is more infectious and faster to spread.
This corresponds to a rise in the R rate of the virus, meaning each infected person passes it on to more others.
N501Y is also found in the Kent variant found in England, and the two Brazilian variants of concern – P.1. and P.2.
What does E484K do?
The E484K mutation found on the South African variant is more concerning because it tampers with the way immune cells latch onto the virus and destroy it.
Antibodies – substances made by the immune system – appear to be less able to recognise and attack viruses with the E484K mutation if they were made in response to a version of the virus that didn’t have the mutation.
Antibodies are extremely specific and can be outwitted by a virus that changes radically, even if it is essentially the same virus.
South African academics found that 48 per cent of blood samples from people who had been infected in the past did not show an immune response to the new variant. One researcher said it was ‘clear that we have a problem’.
Vaccine makers, however, have tried to reassure the public that their vaccines will still work well and will only be made slightly less effective by the variant.
How many people in the UK have been infected with the variant?
At least 105 Brits have been infected with this variant, according to Public Health England’s random sampling.
The number is likely to be far higher, however, because PHE has only picked up these cases by randomly scanning the genetics of around one in 10 of all positive Covid tests in the UK.
This suggests that there have been at least 1,050 cases between December and January 27.
Will vaccines still work against the variant?
So far, Pfizer and Moderna’s jabs appear only slightly less effective against the South African variant.
Researchers took blood samples from vaccinated patients and exposed them to an engineered virus with the worrying E484K mutation found on the South African variant.
They found there was a noticeable reduction in the production of antibodies, which are virus-fighting proteins made in the blood after vaccination or natural infection.
But it still made enough to hit the threshold required to kill the virus and to prevent serious illness, they believe.
‘While it is a difficult choice to make given how long restrictions have already been, yes, some continued restrictions would be in order. I’d recommend working as hard as possible to stamp out these outbreaks.’
Professor Kao said: ‘You won’t be able to do so forever — or at least, can’t guarantee it. But anything to slow down its spread will mean more of the country can continue to have lowered restrictions.’
Gabriel Scally, member of Independent SAGE and visiting professor of public health at the University of Bristol, said urgent action is needed to stop clusters spreading.
He backs plans to increase restrictions where flare-ups occur, including measures like closing schools in areas where the variants are identified.
Forty-four confirmed cases of the B.1.351 variant have been spotted in Wandsworth and Lambeth, with a further 30 probable cases identified.
NHS Test and Trace boss Dr Susan Hopkins called the cluster ‘significant’.
It sparked a huge testing drive for people without symptoms, with large queues lining up outside testing centres yesterday.
Positive samples from the surge testing are being sent to laboratories to determine if the variant is present.
Scientists are concerned that the strain, officially known as B1351, could be resistant to vaccines because its evolved spike proteins allow it to evade immune responses.
Confirmed cases of the variant in the capital have been recorded in Barnet, Croydon, Merton, Redbridge, Ealing, Haringey, Mitcham and Brent to date.
Last night fellow SAGE adviser Professor Peter Openshaw, an expert in experimental medicine, admitted the outbreak had spooked scientists.
Professor Openshaw, of Imperial College London, told BBC2’s Newsnight: ‘A lot of we scientists are very concerned about what’s happening at the moment.
‘I think we’re all just hoping the staged reduction in lockdown is going to be okay. It is being done reasonably cautiously but I think this is not good news.
‘If we get rapid spread of the South African or other more resistant variants, it may well be that we are going to have to put the reductions of lockdown into reverse.’
The ‘stay at home’ order was lifted on March 29 but people are still instructed to ‘stay local’ by current Government guidance.
Restrictions were eased further on Monday, prompted thousands to pack into pub gardens to celebrate the ‘glorious twelfth’.
The next ‘waymarks’ on No10’s ultra-cautious roadmap back to normality are due on May 17 and June 21.
Boris Johnson has previously hinted that tiered lockdowns would not be reintroduced when lockdown ends, saying the virus is now ‘behaving much more nationally’ in February.
The South Africa variant has been spreading in England since late last year but only 544 cases have been officially recorded so far.
At the moment, experts believe the variant does not have an ‘evolutionary edge’ over the current UK dominant Kent strain, which appears to be more transmissible.
But because the South African version has vaccine-resistant abilities, there are fears it could spiral once the Kent strain is squashed by the immunisation programme.
The B.1.351 strain has three key mutations on its spike protein which help it ‘hide’ from the immune system, known as E484K, N501Y and K417N.
Covid uses its spike to latch onto human cells and the current crop of vaccines have been designed to train people’s bodies to recognise that protein.
But any deformities make it harder for the immune system to spot and flush it out, allowing the virus to take hold.
No10’s scientific advisers fear the South African variant — which has yet to take hold in the UK — may make the current crop of vaccines around 30 per cent less effective.
Analysis by SAGE found the strain can cause up to a 10-fold decrease in the effectiveness of antibodies in vaccinated or previously infected people.
While antibodies are not the only part of the immune response against Covid — white blood cells also help — they play a crucial role in fighting off the infection.
Nonetheless, experts are still confident the jab is strong enough to protect the vast majority of people from falling severely ill with the B.1.351 strain.
South Africa — which has been ravaged by the variant — has already suspended the use of AstraZeneca’s vaccine, citing concerns it is not effective enough.
And real-world data from Israel last week suggested the strain may also evade the protection provided by Pfizer’s vaccine to some extent.
But separate studies have sought to downplay fears, with one suggesting the Pfizer jab offers 100 per cent protection against the Brazilian and South African variants.