Health officials warn of two new Omicron variants of concern

Two types of the Omicron variant of Covid-19 have been newly classified as variants of concern.

Only a small number of cases of Omicron BA.4 and BA.5 have been identified so far, but analysis of the available data suggests they are likely to have a “growth advantage” over Omicron BA.2, currently the dominant variant, according to the UK Health Security Agency (UKHSA).

As of May 20, 115 cases of probable or confirmed BA.4 had been identified, with 67 in England, 41 in Scotland, six in Wales and one in Northern Ireland.

Some 80 cases of BA.5 have been identified, with 48 in England, 25 in Scotland, six in Northern Ireland and one in Wales.

South Africa

Both variants were initially identified in South Africa, one of the few countries that are still sequencing large numbers of Covid-19 tests.

There has been a rapid increase in positive tests for Covid-19 in South Africa, and authorities believe that BA.4 and BA.5 are responsible.

The National Institute of Clinical Diseases in South Africa reports that BA.4 and BA.5 are “Omicron viruses with a new combination of mutations.”

Scientists first detected BA.4 on 10 January 2022, and it has since spread throughout South Africa, making up 35% of positive tests.

BA.5 was identified on 25 February and now accounts for 20% of cases in several South African regions.

Both subvariants are similar to Omicron BA.2 but so far there is no indication that BA.4 or BA.5 are associated with new symptoms or more severe disease.

Health officials say they are confident that vaccines should protect against severe disease from the new variants.