Overview

• WHO genomic surveillance from late September shows XFG sublineages leading UK sequences, including 35% XFG.3 and 28% XFG, with NB.1.8.1 at 11%.
• Doctors report Stratus infections often feature a hoarse or gravelly voice, while Nimbus is frequently linked to a very painful sore throat and more gastrointestinal issues.
• WHO and UKHSA say current evidence does not indicate increased severity from these variants, and WHO assesses the added public-health risk from Stratus as low.
• Vaccination remains effective at preventing severe disease, with NHS and devolved programs inviting eligible groups such as older adults and immunosuppressed people to take up boosters.
• Nimbus holds WHO Variant Under Monitoring status, and early reports suggest higher ACE2 receptor affinity and a recombination origin, which researchers continue to observe.