evidence: Annex: UKHSA clinical advice on the emerging risk of BA.2.86 UKHSA conducts routine monitoring and surveillance of COVID-19 and the emergence and spread of new variants internationally. A new variant, BA.2.86 was identified due to its high number of mutations. The mutations, including many in spike protein, mean that the variant may be antigenically altered compared to previously circulating variants, and other changes in viral properties are also possible. There are a small number of cases identified globally but as genomic surveillance is now very limited internationally, there is a very high degree of uncertainty about the spread and growth of this variant at present and the situation is dynamic. It will take a period of several weeks to grow the virus and confirm its biological properties, and epidemiological studies cannot be conducted until there are a larger number of cases to include. Should this variant cause an increase in transmission, the earliest epidemiological signal may be from increasing hospital admissions in the UK or other countries. Waiting to respond until this data is available will mean that any interventions are unlikely to change the impact on health services.