Virologists have voiced concerns about the emergence of another fast-spreading Omicron variant that is rapidly gaining ground in India and has already arrived in the United Kingdom.
The BA.2.75 variant – nicknamed Centaurus – was first detected in India in early May. Cases in the United Kingdom have since risen steeply – and apparently faster than those of the extremely transmissible BA.5 variant, which is also present in India and is rapidly displacing the previously dominant BA.2 variant in many countries.
BA.2.75 has also since been detected in about 10 other countries, including the United Kingdom, United States, Australia, Germany and Canada.
The European Centre for Disease Prevention and Control (ECDC) designated it a “variant under monitoring” on July 7th, meaning there is some indication that it could be more transmissible or associated with more severe disease, but the evidence is weak or has not yet been assessed.
The World Health Organisation (WHO) is also closely monitoring the new variant, although its chief scientist, Dr Soumya Swaminathan, said there were not yet enough samples to assess its severity.
In addition to its apparent rapid growth and wide geographical spread, virologists have been alerted by the sheer number of extra mutations BA.2.75 contains, relative to BA.2, from which it is likely to have evolved.
“This could mean that it has had the chance to evolve an advantage over an already successful virus lineage,” said Dr Stephen Griffin, a virologist at the University of Leeds.
“It’s not so much the exact mutations, more the number/combination,” said Dr Tom Peacock, a virologist at Imperial College London, who was the first to identify Omicron as a potential concern back in November 2021. “It’s hard to predict the effect of that many mutations appearing together – it gives the virus a bit of a ‘wildcard’ property where the sum of the parts could be worse than the parts individually.
“This time last year, many were convinced that Delta represented an evolutionary pinnacle for the virus, but the emergence of Omicron and the vast increase in variability and antibody evasiveness is a sign that we cannot as a population follow an influenza-like plan to keep pace with viral evolution,” said Dr Griffin.
In addition to vaccines, longer-term plans should include variant-agnostic measures to prevent infections and reinfections. “This includes creating infection-resilient environments through improved ventilation, filtration, or sterilisation of indoor air, sensible reprovision of lateral flow tests, and appropriate and supported isolation periods that will actually reduce ongoing transmission,” he said. — Guardian