Fears are growing about the new Botswana Covid-19 variant which experts believe is the most mutated version of the virus to date.
The B.1.1529 strain, which could soon be named Nu, carries 32 mutations of which many are highly transmissible and vaccine resistant.
So far, only 10 cases of the strain have been recorded worldwide but it has already been identified in three countries.
The first infections were spotted in Botswana, followed by another six cases in South Africa and one in Hong Kong involving a traveller returning from South Africa.
Scientists say the variant has more changes to its spike protein than any other and that it possibly emerged from a person with undiagnosed AIDS.
Professor Francois Balloux, a geneticist at University College London, said: “B.1.1529 is a new lineage that has been found in Botswana that carries an unusual constellation of mutations.
“Given the large number of mutations it has accumulated apparently in a single burst, it likely evolved during a chronic infection of an immunocompromised person, possibly in an untreated HIV/AIDS patient.”
He said the variant is difficult to predict at this stage. He suggested this new variant would not necessarily be recognised by the immune systems of those infected by Alpha or Delta variants.
Spike mutations generally allow viruses to adapt and become more severe and better at resisting natural and vaccine immunity.
Dr Tom Peacock, of Imperial College London, warned that the variant “very very much should be monitored due to that horrific spike profile”.
Worth emphasising this is at super low numbers right now in a region of Africa that is fairly well sampled, however it very very much should be monitored due to that horrific spike profile (would take a guess that this would be worse antigenically than nearly anything else about)
— Tom Peacock (@PeacockFlu) November 23, 2021
Key mutations of the Botswana variant include E484A, K417N and N440K, which can escape antibodies.
The N501Y mutation is also of concern and speeds up the spread of the virus.
Prof Balloux added: “So far, four strains have been sequenced in a region of Sub-Saharan with reasonable surveillance in place. It may be present in other parts of Africa.
“For the time being, it should be closely monitored and analysed, but there is no reason to get overly concerned, unless it starts going up in frequency in the near future.”
There are no cases in the UK but the Health Security Agency said it was monitoring the situation closely.
A Number 10 spokesman said: "We continue to monitor new variants as they emerge with our partners around the world.
"We have one of the largest genomic sequencing programmes here in the UK that allows us to spot and track variants as they emerge and, as we have done throughout the pandemic, we will continue to keep an eye and keep this particular variant under investigation."
Asked whether travel restrictions would be needed before Christmas as a result of the variant, the spokesman said: "We will continue to keep the latest situation, the latest scientific evidence and data, under review, as we have done throughout the pandemic.
"We have said before if we believe we need to take action we will, but we will continue to monitor this variant and other variants in the same way that we have done throughout the pandemic."
Prof Ewan Birney, Deputy Director General of the leading European Molecular Biology Laboratory and Director of the European Bioinformatics Institute, said: “Early evidence from genomic surveillance in South Africa suggests that B.1.1.529 is a serious cause for concern. The South African surveillance and epidemiology groups should be commended for their timely data collection, analysis and transparency.
“Armed by our experience and understanding of the Alpha and Delta variants, we know that early action is far better than late action. It may turn out that this variant is not as large a threat as Alpha and Delta, but the potential consequences of not acting on the possibility it could be are serious.
“Measures to prevent this variant of concern from spreading include implementing appropriate quarantine and PCR testing measures and sequencing on international travel from Southern Africa and continue careful monitoring of the circulating SARS-CoV-2 variants. The international community should get drugs and vaccines to South Africa as soon as possible. All countries should remain vigilant and share SARS-CoV-2 genomes.”
Botswana recorded 207 new Covid infections and zero deaths in the last seven day period up to November 22, according to the World Health Organization.