The number of coronavirus infections across the UK rose by an estimated 1m compared with the previous week, with figures in Scotland at a record high, data from the Office for National Statistics has revealed. According to the latest information from the ONS, based on swabs collected from randomly selected households, an estimated 9% of the population in Scotland had Covid in the week ending 20 March, about one in 11 people. The figure is the highest recorded by the survey since it began looking at the situation in Scotland in October 2020. Infection levels also increased in England and Wales, although they decreased slightly in Northern Ireland, with data revealing that about one in 16 people in England had Covid in the most recent week, compared with one in 20 the week before, a rise from about 2,653,200 to 3,485,700 people. The figure is just shy of the all-time high for England, when about 1 in 15 were estimated to have Covid in the week between Christmas and New Year’s Eve last year, at the height of the Omicron wave. Experts have suggested that the recent surge in infection levels in the UK is owing to a number of factors, including the lifting of Covid restrictions to various degrees across the UK, changes in behaviour, waning immunity after the booster programme and – crucially – the rise of the BA.2 variant, which appears to be more transmissible than the earlier form of Omicron. “The percentage of people with infections compatible with the Omicron BA.2 variant increased in England, Wales and Scotland and decreased in Northern Ireland,” the ONS report states. Previous ONS figures have suggested that Northern Ireland experienced a rise in BA.2 before other parts of the UK. On Friday, the UK Health Security Agency reported that cases of the BA.2 Omicron variant were increasing 75% faster than the original variant, BA.1, and now made up almost 89% of Covid infections sequenced in England. There is no evidence that BA.2 causes a greater risk of hospitalisation. The agency is also monitoring three “recombinant” forms of the coronavirus that can occur when a person is infected with two Covid variants at once. The first, a mix of Delta and BA.1, known as XF, caused a small cluster in the UK but has not been spotted since mid-February. The second, XE, is a combination of BA.1 and BA.2 and is spreading about 10% faster than BA.2 in the UK, with 637 cases identified as of 22 March. The third, XD, is another blend of Delta and BA.1. While it has not yet reached the UK, it has surfaced in France, Belgium and Denmark, and scientists are watching it closely because it is essentially the Delta variant with the Omicron spike protein. The ONS figures also show that infection levels rose in all age groups in England. While the percentage of people testing positive was highest in children between two years old and school year 6, infection levels reached unprecedented levels in older adults: among those who are 70 or over, the figure hit an estimated 5.7% on 19 March. While all regions of England experienced a rise, the highest levels of infection were in the south-east, with about 7.5% of people – or one in 13 – estimated to have had Covid during the week. Sarah Crofts, the head of analytical outputs for the Covid-19 Infection Survey, said: “Our latest data show infection levels have continued to increase in England, Wales and Scotland, driven by the rise of the Omicron BA.2 variant. “Northern Ireland was a few weeks ahead of the rest of the UK in this rising variant, where we now see a welcome decrease. Meanwhile, Scotland has now reached the highest level of any UK country seen in our survey. “Across England, infections have increased in all regions and age groups, notably the over-50s, who are at their highest levels since our survey began.” The figures come the week before free community testing ends for most people. After 1 April, most people in England will have to pay to take a Covid test, while advice to stay at home if someone has Covid symptoms is also set to be scrapped. While vaccinations, improved treatments and a shift in variant severity have all helped to weaken the link between infections, hospitalisations and deaths, the recent surge in the number of people with Covid has nonetheless affected the NHS, with an uptick in hospitalisations – including an increase in those primarily being treated for Covid – increasing concerns about infections in vulnerable people and posing logistical challenges. Some hospitals have suspended visiting because of rising infection levels.