A new Covid variant named BA.2.86 has been detected in the UK.

Here’s what we know – and don’t know – so far.

What is the BA.2.86 variant?

BA.2.86 was first detected in Denmark on 24 July 2023 and has also been found in Israel and the US.

It was identified in the UK on 18 August in someone who hadn’t recently been abroad, which “suggests a degree of community transmission within the UK,” the UK Health and Security Agency (UKHSA) said. Community transmission is when an infection is passed between people in the same country, rather than being introduced by someone travelling into the area.

It is thought to be related to the BA.2 variant, which was nicknamed “stealth Omicron” and originated in southern Africa before first being detected in the UK by late 2021.

Is the new Omicron variant more severe?

The UKHSA said there is “insufficient data” on how severe the new strain might be or how likely it could evade protection from vaccines.

It’s not yet a “variant of concern”, a label usually assigned to variants that spread quickly or cause severe infection.

The UKHSA said it will continue to monitor the situation closely and will publish the results of its analysis when it’s available.

The high number of mutations in this Omicron virus means that spike proteins – the membranes on the outside of the virus that allow it to enter and infect human cells – will change their shape.

Martin Michaelis, professor of molecular medicine at the University of Kent, told FactCheck this may mean “that this is a new escape variant that can better bypass immune protection provided by vaccinations and previous infections”.

But although Prof Michaelis told us it is “not clear” whether BA.2.86 may be more severe than infections caused by other recent variants, the high level of immunity in the population due to vaccination and previous infections makes it “unlikely” to cause “more serious disruptions as seen earlier in the pandemic”.

This is echoed by Professor Francois Balloux, from UCL Genetics Institute, who told the Science Media Centre last week: “Most people on earth have now been vaccinated and/or infected by the virus. Even if people get reinfected by BA.2.86, immune memory will still allow their immune system to kick in and control the infection far more effectively.”