The latest Covid-19 variant, BA.2.86, appears to be spreading in the UK, health surveillance data suggests.
The variant, nicknamed Pirola, has prompted concern among scientists because of the high number of mutations it carries, which raises the possibility that it could evade the immune system more easily or be more transmissible.
In a briefing note on Friday, the UK Health Security Agency (UKHSA) said that an outbreak at a care home in Norfolk and other cases across the UK indicated there was likely to be community transmission of the strain, but said it was too early to judge the full extent of its spread.
In an outbreak of Covid-19 in a care home in Norfolk at the end of August, 33 out of 38 residents tested positive for the virus, along with 12 members of staff, the UKHSA said. One resident needed hospital treatment but no deaths were reported. Laboratory tests later showed that 22 residents had the BA.2.86 variant, along with six staff.
The outbreak was “an early indicator” that the variant may be sufficiently transmissible to have an effect in close-contact settings, the UKHSA said, though it was too early to draw any conclusions about how BA.2.86 would behave in the wider UK population.
Twenty-nine of the 33 residents at the care home who tested positive for Covid-19 have recovered, along with all members of staff, the UKHSA added.
Dr Renu Bindra, the UKHSA incident director, said that while BA.2.86 had a “significant number of mutations” compared with other variants circulating, the data so far was “too limited to draw firm conclusions” about the impact this would have on the transmissibility or severity of the virus.
“It is clear that there is some degree of widespread community transmission, both in the UK and globally, and we are working to ascertain the full extent of this,” she said. “In the meantime, it remains vital that all those eligible come forward to receive their autumn vaccine as soon as it is offered to them.”
Some early lab-based evidence has eased initial concerns about the potential of BA.2.86 to cause a new global wave of infection, as happened with the emergence of Omicron. A pre-print study, from researchers in China, found that BA.2.86 is not as efficient at infecting cells in the lab compared with other circulating Omicron subvariants. Another pre-print study from researchers in Sweden found only modest drops in how well serum from blood donors could neutralise BA.2.86 compared with other variants.
The latest Covid-19 vaccine booster programme has been brought forward from October to September as a precaution against BA.2.86. The booster programme will begin in England on 11 September, with jabs offered first to residents of adult care homes and clinically vulnerable people, before it is extended to everyone in the UK aged 65 and above.