The “largest surge testing operation” to date is underway in parts of south London after 44 cases of Covid-19 infection with the South Africa variant of concern were confirmed.
They have been found predominantly in Wandsworth and Lambeth, according to the Department of Health and Social Care (DHSC), with a further 30 “probable” cases of the variant identified.
People aged 11 and over who live, work or travel through those areas are being urged to take a Covid-19 polymerase chain reaction (PCR) test, on top of using twice-weekly rapid testing.
There are currently four variants of concern on UK soil. But what makes a variant ‘cause for concern’? Well, viruses mutate quite often and most of the time, they mutate in a way that doesn’t change much about their characteristics.
There are around one to two mutations of SARS-CoV-2 per month, which means many thousands of mutations have developed since the virus emerged in 2019, according to the Covid-19 Genomics UK Consortium.
“Most of these mutations have no effect on the behaviour of the virus but occasionally a mutation occurs that alters how quickly the virus spreads, how infectious it might be or even the severity of the disease it causes,” says Professor Lawrence Young, a virologist and expert in molecular oncology from Warwick Medical School. “It is then the virus becomes a variant of concern.”
Here’s what we know about the four variants of concern in the UK.
The Kent variant
This variant, known as VOC202012/01, was first detected in the UK in September 2020. It includes multiple mutations in the spike protein, which is the part of the virus that first attaches to a human cell and then infects us.
These changes have resulted in the virus becoming about 50% more infectious, according to Public Health England (PHE), meaning it’s spreading far more easily between people. It’s the most dominant variant of concern in the UK.
Two studies found no evidence that people with the variant have worsened symptoms or a heightened risk of developing long Covid. However they did confirm that it increases transmission, finding that viral load and the reproduction (R) number were higher.
The South Africa variant
This variant, called VOC202012/02 or 501 Y.V2, appears to have emerged around the same time as the variant originating in the UK – but in South Africa.
It shares the same mutation to the spike protein as the UK variant, but also has a number of other mutations including E484K.
It’s thought the E484K mutation may be able to escape the body’s antibodies to some extent and is therefore of potential public health concern. The main worry being that it could impact vaccine effectiveness.
People in certain parts of the UK where this variant is spreading are being asked to stay home and undergo “surge testing” to minimise its spread.
The Brazil variant
This particular variant of concern – called P.1 – was first identified in Manaus, Brazil. The variant shares important mutations with the variant first identified in South Africa – meaning it may respond less well to current vaccines and might be more infectious. There is no indication that this virus variant is associated with more severe disease, says Prof Young.
“P.1 is associated with a surge of cases in Manaus late last year which experienced a second severe wave of Covid-19,” says Professor Nick Loman, of the Institute of Microbiology and Infection at University of Birmingham.
“This was concerning as it raises the possibility it is able more easily re-infect patients due to the mutations it carries. However the evidence for this is currently limited.”
The Bristol variant
This variant, called VOC 202102/02, is the most recently discovered variant in the UK.
The Bristol mutation – colloquially named so because it was first discovered in the city – is a variant of the strain identified in Kent, meaning it’s likely to be more transmissible. Like the South Africa variant, it also carries the spike mutation E484K, which experts suggest may be better at evading the human immune response – and therefore could have an impact on vaccines.
PHE notes it’s “very unusual for any variant virus to render a vaccine completely ineffective”, however variants can alter the performance of vaccines.
Prof Young says it’s “likely” we’ll see more variants of concern, “as the virus adapts to our bodies and learns ways to dodge our immune response”.
“The more the virus spreads, the more chances it has to evolve and to pick up other mutations,” he explains.
“So getting vaccines rolled out quickly along with other ways to prevent transmission – social distancing, etc – will help stop infection and the generation of new variants. Whatever virus variants may arise, they are all transmitted in the same way: person to person contact.”