Covid-19 infections in the UK increased by 43 per cent in the week after the Platinum Jubilee celebrations, according to new estimates.
The Omicron variants BA.4 and BA.5 are believed to be behind the sudden increase, though scientists said the mass gatherings over the long weekend “would certainly not have helped”.
The number of people in hospital with and because of Covid is also showing signs of an upwards trend, suggesting the virus is once again becoming more prevalent across the country.
A total of 1.4 million people in private households are estimated to have had the virus last week, up from 989,800 the previous week, according to the Office for National Statistics (ONS).
Total infections are now back at levels last seen at the start of May, but remain well below the record 4.9 million at the peak of the Omicron BA.2 wave at the end of March. Covid hospital admissions are also below the levels recorded during the previous wave.
The ONS said the latest increase was “likely caused by infections compatible with Omicron variants BA.4 and BA.5”, which are now thought to be the most dominant variants in much of the UK.
Professor Christina Pagel, the director of the Clinical Operational Research Unit at University College London, echoed this.
“While the jubilee celebrations would certainly have not helped,” she said, “the current wave is precipitated mainly by BA.4/BA.5 and BA.2.12.1 becoming dominant and driving a new surge, likely due to greater ability to escape immunity from previous infection and vaccines.”
BA.2.12.1 is another sub-strain of the original Omicron variant that is believed to be more transmissible than its predecessor.
BA.4 and BA.5 have meanwhile been classified as “variants of concern”, after analysis found both were likely to have a growth advantage over Omicron. However, the two stains are not believed to any more deadly than previous variants.
Dr Mary Ramsay, from the UK Health Security Agency, said: “It is encouraging that we are not seeing an increase in intensive care unit admissions, but we are monitoring data closely and assessing the possible impact of sub-variants BA.4 and BA.5.
“As we enter summer, it’s still important to remember that Covid-19 has not gone away, and to get vaccinated to reduce the risk of becoming seriously ill with the virus.”
In England, 1.1 million people were likely to test positive for Covid-19 last week, the equivalent of around one in 50, the ONS said. This is up week-on-week from 797,500, or one in 70. Wales has seen infections rise to 64,800 people, or one in 45, up from 40,500, or one in 75.
The virus is estimated to be most prevalent in Scotland, where 176,900 people were likely to have tested positive last week, or one in 30, up from 124,100, or one in 40. Northern Ireland has seen Covid-19 infections jump to an estimated 42,900 people, or one in 45, up from 27,700, or one in 65.
The latest dataset published by the ONS is likely to cover the fallout from the Platinum Jubilee, during which millions gathered across the country in close proximity to celebrate the Queen’s 75 years on the throne.
Those infected with the virus will have started showing symptoms or testing positive in the days after the long weekend.
Professor Irene Petersen, an epidemiologist at UCL, said that while the “Jubilee celebrations may have brought people together, many of these events were outdoor.”
She said the rise in infections was “expected for some time” due to the circulation of BA.4 and BA.5.
Infection levels for the week ending 11 June are highest among 50 to 69-year-olds, where 2.7 per cent — one in 35 — were likely to have had the virus last week. Prof Petersen said “we should keep an eye” on this age group “as there are still quite a large proportion who haven’t been tripled vaxed”.
The estimates are the latest in a series of figures in recent days to suggest a rise in prevalence of the virus is under way.
The number of people in hospital in the UK with Covid-19 has started to increase, though the trend is not identical across the country.
Some 5,008 patients in England had Covid-19 on June 16, up 23 per cent on the previous week, while in Scotland 748 patients were recorded on June 12, the latest date available, up 17 per cent.
There is no evidence of an increase in intensive care unit admissions, however. The number of registered deaths involving coronavirus also remains low.