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.
Dr Meera Chand, Director of Clinical and Emerging Infections at UKHSA, said: "The reclassification of these variants as variants of concern reflects emerging evidence on the growth of BA.4 and BA.5 internationally and in the UK. Whilst the impact of these variants is uncertain, the variant classification system aims to identify potential risk as early as possible.
"UKHSA is undertaking further detailed studies. Data and analysis will be released in due course through our regular surveillance reporting."
The news of the variants' new classification came as Covid-19 infections in the UK fell to their lowest level for five months, according to the Office for National Statistics (ONS). A total of 1.3 million people in private households are estimated to have had the virus in the week to May 13, down from 1.5 million the previous week.
It is the lowest estimate for infections since early December, when virus levels were just starting to rise due to the spread of the original Omicron variant.
In England, infections have fallen for the sixth week running, with 1.0 million people likely to test positive for Covid-19, the equivalent of around one in 55. This is down week-on-week from 1.2 million, or one in 45.
Wales has seen Covid-19 infections drop for the fifth week in a row, with 80,700 people estimated to have coronavirus, or one in 40, down from 88,300, or one in 35.
In Scotland, 122,200 people were likely to test positive for the virus in the seven days to May 13, or around one in 45. This is down from 158,200 people, or one in 35, the previous week.
The virus continues to be least prevalent in Northern Ireland, where infections are now at their lowest level since early November.
Some 29,800 people were estimated to have Covid-19 last week, or one in 60, down from 33,800, or one in 55.
