A new Covid-19 variant, named Stratus and classified as XFG and its sub-lineage XFG.3, has become the dominant strain in England, accounting for approximately 60% of cases as of late June. The variant was designated a 'variant under monitoring' by the World Health Organisation on 25 June due to its rapidly growing prevalence, though there is currently no evidence it poses additional health risks compared to previous strains.
Despite the surge, experts indicate that a significant summer wave has not materialised. UK Health Security Agency (UKHSA) data shows Covid cases have risen by only 20% since mid-April. Professor Christina Pagel of University College London noted in a blog post on 10 July that while the Stratus variant and another new variant, Nimbus, were expected to cause a summer wave, this has not occurred, likely due to the unusually warm and dry weather improving ventilation and reducing indoor crowding.
Professor Lawrence Young, a virologist at Warwick University, commented that recent heatwaves have helped prevent infections by encouraging more time outdoors and better air circulation. However, he cautioned that the virus continues to evolve, and the risk of a later surge remains. Current vaccines are expected to be effective against the new variant, and the NHS has invited eligible individuals to receive a free 'Autumn Booster' Covid jab from 1 October.
While no Covid restrictions are in place, health officials advise those with the virus to stay at home. Some experts note that the Stratus strain may cause a hoarse voice, a symptom not typical of other variants.
