Concern is growing over two new sub-variants of Covid-19 that have driven up infection rates in the UK, inspiring fears that other countries could soon likewise see a resurgence in cases.
Known as BA.4 and BA.5, the strains were discovered in South Africa in January and February respectively and are effectively the grandchildren of the Omicron variant of the coronavirus, which spread across the globe in late 2021, and feature three mutations to their spike proteins, which, it is feared, enable them to retrain their attack on human lung cells.
