Two new sub-variants of Covid-19 drove up infection rates in the UK between the start of June and mid-July before suddenly tailing off, nevertheless providing a timely reminder that the threat from the virus has not gone away.
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.
