More on that:
LONDON/COPENHAGEN, Jan 21 (Reuters) - The UK Health Security Agency on Friday said it had designated a sub-lineage of the dominant and highly transmissible Omicron coronavirus variant as a variant under investigation.

BA.2, which does not have the specific mutation seen with Omicron that can be used as a proxy to easily distinguish it from Delta, is being investigated but has not been designated a variant of concern.

From: Reuters