A Covid variant thought to carry more mutations than any other strain has been found in Tanzania, according to researchers.
Virologists said it looked further removed from the original Wuhan virus than any other strain known to science, including variants found in Kent, South Africa and India.
It was first picked up in three travellers who got tested at an airport in Angola after flying there from Tanzania in mid-February.
Researchers examined samples in a laboratory and found the virus had 34 changes, 14 of which were on the ‘spike’ protein that it uses to latch onto human cells and cause illness.
For comparison, the Kent variant has 17 significant genetic changes with eight on the spike. The South African strain has even fewer.
Professor Tulio de Oliveira, who discovered the variant, said: ‘When compared with other variants of concern and variants of interest, this is the most divergent one.’
He described the strain, known as A.VOI.V2 as ‘the most diverse A lineage ever described’. An A lineage is a direct descendent of the original Wuhan strain of the virus.
This comparison doesn’t include the Kent and South African variants, however, which are B lineages – ones that trace back to a different strain that became dominant in Europe last summer.
Not enough is known about the Tanzanian variant for scientists to decide whether it is any more dangerous than existing ones.
And it’s impossible to know how widespread it is because not enough testing and genetic sampling is done in sub-Saharan Africa.
Professor Tulio de Oliveira said A.VOI.V2 was ‘potentially of interest’ simply because of how many mutations it has.
Professor de Oliveira published his discovery alongside colleagues at the University of KwaZulu-Natal in Durban, South Africa; the Angola Ministry of Health; the Africa Centres for Disease Control and Prevention; and universities in Rio de Janeiro, Oxford and Cape Town.
Professor de Oliveira said on Twitter: ‘It the most diverse A lineage sequencers ever described.
‘It also [worried] us as it was found in three travelers from Tanzania in Angola. There is almost no data from Covid in Tanzania.
‘When compared with other variants of concern and variants of interest, this is the most divergent one.’
Graphs published in the paper only compared it to five other major variants and suggested some samples of those had contained more mutations than the Tanzania strain. Not every sample is identical and some have extra mutations that come and go because the virus is constantly changing and not every change sticks around.
The reason a large number of mutations is concerning for scientists is that it raises the risk of immunity from a vaccine or past infection not working as well.
Immune system antibodies, which destroy the virus when it gets into the body, are specific and work less well against viruses they haven’t seen before.
