Two variants of Omicron have been raised to the level of 'variants of concern' by the UK Health Security Agency as dozens of cases are identified. The variants are Omicron BA.4 and Omicron BA.5.
In the latest figures from Tuesday, May 17 there have been 115 cases of BA.4 and 80 cases of BA.5 confirmed in England. While both variants are in the early stages of growth in the UK, analysis of the data suggests that they are likely to have a growth advantage over the currently-dominant Omicron BA.2 variant.
There can be several reasons for growth advantage, but in the case of BA.4 and BA.5, laboratory data suggests a degree of immune escape which is likely to contribute.
