A new SARS-CoV-2 subvariant with a high number of mutations that could help it neutralise the immune system has emerged in four countries, raising alarm among scientists.
“BA.2.86 is the most striking SARS-CoV-2 strain the world has witnessed since the emergence of omicron,” said Francois Balloux, professor of computational systems biology and director of University College London’s Genetics Institute.
Genetic sequencing has found BA.2.86 in six covid cases so far, the earliest being in Denmark on 24 July. The other cases were from Israel, the UK, and the US. None of the cases seem linked. The UK Health Security Agency said that the UK case was in a person with no recent travel history, suggesting a degree of community transmission within the UK.
The genetic diversity suggests that BA.2.86 has been in circulation for months, said Balloux. “Interestingly, all 30-plus mutations on that long branch are found in the spike protein—through which the virus gains entry to cells—which is the target of neutralising antibodies.”
BA.2.86, which some media outlets have nicknamed “Pirola,” is another subvariant of the omicron variant, this one descending from the BA.2 strain that led to widespread covid cases at the start of 2022. The new strain has 34 more mutations than BA.2 and 36 more than XBB.1.5 (dubbed “Kraken” in the media1 and the strain recommended for vaccination), said an early analysis by Jesse Bloom, a computational virologist at the Fred Hutchinson Cancer Research Institute in Seattle, USA.2
BA.2.86 has “at least as much” antibody escape as XBB.1.5 did when compared with BA.2, meriting high priority monitoring for signs of spread, Bloom wrote. The World Health Organization has labelled BA.2.86 a “variant under monitoring”—its second tier of notable covid variants.
The mutations give BA.2.86 “all the hallmark features of something that could take off,” said Kristian Andersen, an immunologist at the Scripps Research Institute in the US, writing on the social media platform X (formerly Twitter). He added, “Our immunity landscape is now complex so it’s too early to say it will. I think it might.”