British scientists have raised the alarm over a new Covid variant believed to have emerged in Botswana that is the most highly mutated version of the virus to date.
Although only 10 infections have been detected so far, the variant has already been recorded in three countries, suggesting it is more widespread.
Expected to be given the name "Nu", the strain carries 32 mutations, many of which suggest it is highly transmissible and vaccine-resistant, and has more alterations to its spike protein than any other variant.
University College London reported it likely emerged in a lingering infection in an immunocompromised patient, possibly someone with undiagnosed Aids.
Changes to the spike make it difficult for existing vaccines to fight off, because they train the immune system to recognise an older version of this part of the virus.
Tom Peacock, a virologist at Imperial College who first picked up on its spread, described the variant's combination of mutations as "horrific".
He warned that B.1.1.529, its scientific name, had the potential to be "worse than nearly anything else about", including the world-dominant Delta strain.
Victim of its own success?
However, scientists maintian that its unprecedented number of mutations might work against it and make it "unstable", preventing it from becoming widespread.
They said there was no need to be overly concerned because there were no signs yet that it was spreading rapidly.
Three infections have been detected in Botswana to date and six in South Africa, where variant surveillance is more robust.
One case has also reportedly been spotted in a 36-year-old man in Hong Kong who recently returned from the continent.