A South African Covid variant "could be more infectious" than other mutations and may have the potential to evade vaccines, scientists warn.
The C.1.2 strain was first identified by scientists in South Africa in May and has since been found in England, China, the Democratic Republic of the Congo, Mauritius, New Zealand, Portugal and Switzerland.
The strain has been linked to 'increased transmissibility' and now said to be more mutations away from the original virus which was first seen in Wuhan, China.
According to experts at South Africa's National Institute for Communicable Diseases and the KwaZulu-Natal Research Innovation and Sequencing Platform, the C.1.2 strain has a mutation rate of about 41.8 mutations per year.
This is nearly double the current global mutation rate seen in any other Variant of Concern (VOC) to date.
Researchers discovered a monthly increase in the number of C.1.2 genomes in South Africa, rising from 0.2 per cent in May to 1.6 per cent in June and 2.0 per cent in July.
The Alpha, Beta and Gamma variants have also shown a short period of consistent increase.
Scientists also found 14 mutations in nearly 50 per cent of the variants which had a C.1.2 sequence.
While more research is needed 'to determine the functional impact of these mutations', scientists have warned that the latest variant, which has 'mutated substantially', could help the virus evade antibodies and immune responses.
In the report, which was published in the journal Nature, the scientists said: "We describe and characterise a newly identified SARS-CoV-2 lineage with several spike mutations that is likely to have emerged in a major metropolitan area in South Africa after the first wave of the epidemic, and then to have spread to multiple locations within two neighbouring provinces.
"We show that this lineage has rapidly expanded and become dominant in three provinces, at the same time as there has been a rapid resurgence in infections.
"Although the full import of the mutations is not yet clear, the genomic and epidemiological data suggest that this variant has a selective advantage—from increased transmissibility, immune escape or both.
"These data highlight the urgent need to refocus the public health response in South Africa on driving transmission down to low levels, not only to reduce hospitalisations and deaths but also to limit the spread of this lineage and the further evolution of the virus."
Public Health England published a report earlier this month which revealed that the C.1.2 strain was among 10 variants being monitored by scientists in the UK.
In April, scientists found another South African strain — called B.1.351 — had the potential to 'break through' the Pfizer jab.
The study compared almost 400 people who had tested positive for Covid-19, 14 days or more after they received one or two doses of the vaccine, against the same number of unvaccinated patients with the disease.
The Pfizer vaccine appeared to be less effective against the South African variant, researchers said, and has the ability to 'evade' protection.
"We found a disproportionately higher rate of the South African variant among people vaccinated with a second dose, compared to the unvaccinated group. This means that the South African variant is able, to some extent, to break through the vaccine's protection," said Tel Aviv University's Adi Stern.
While the results of the study may cause concern, the low prevalence of the South African strain among those tested was encouraging, according to Stern.
"Even if the South African variant does break through the vaccine's protection, it has not spread widely through the population," he said, adding that the British variant may be "blocking" the spread of the South African strain.
The B.1.351 has key mutations on its spike protein which scientists fear might make it difficult for the immune system to recognise.
Last month health chiefs spotted another Covid variant spreading in Britain, with 31 mutant strains now on the UK's watchlist.
Last week an expert said a coronavirus "super variant" worse than Covid-19 could emerge next year and every unvaccinated person is a potential super-spreader.
Immunologist Professor Doctor Sai Reddy, of the federal technology institute ETH Zurich, said a combination of existing strains could result in a new and more dangerous phase of the pandemic.
He warned: "Covid-22 could be even worse than what we are experiencing now."
As a result, multiple vaccinations will need to be prepared over the next few years as the world continues to fight the evolving threat, "maybe for the rest of our lives".