In late October, the UK Health Security Agency assigned variant designations to two new omicron “grandchildren”: BQ.1 and XBB. This means they will be monitored by health authorities, but are not at this stage regarded as variants of concern.
If we think of the omicron variant as a family tree, BA.2 (the dominant strain in the UK in spring of 2022) is the parent of BA.5 (the variant currently dominant in the UK) and the grandparent of BQ.1. In other words, BQ.1 is a sub-lineage of BA.5.
