UK coronavirus cases rebound, led by rise in infections among schoolchildren, major symptom-tracking study finds, as Omicron BA.2 subvariant shows early signs of being able to outperform the Omicron BA.2 variant origin.
There were 159,586 daily new symptomatic cases of Covid-19 across the UK on January 24, according to estimates by UK symptom tracking app Zoe, up 10% from the 144,527 cases reported a week earlier. The number of cases had peaked at nearly 210,000 in early January.
The rise in cases was driven by a rapidly rising infection rate among those under 18 that “has accelerated, to an all-time high,” the study notes. Cases are also “spilling over” into their parents’ age group, with infections also increasing among people aged 35 to 55.
The new data comes as England on Thursday dropped the latest of its Plan B measures of compulsory mask-wearing in shops and on public transport and requiring vaccination passports for major events.
Tim Spector, professor of genetic epidemiology at King’s College London who is leading the study, said: “The rebound in case numbers just as we are lifting restrictions has come earlier than expected.”
He pinned the spike in schools returning after the holidays, paving the way for a “rapid rise” in cases among children who then “pass” to parents and school staff.
Spector also warned that “another emerging factor” in the rise in cases was the BA.2 subvariant of Omicron, which he said was “probably more contagious” than the original. The UK Health Safety Agency last week designated the subtype as a “study variant”, citing an “increased growth rate” compared to the earlier form of Omicron.
In the UK, the subvariant accounted for 1% of genomically sequenced cases uploaded to the global Gisaid repository in the week to January 23, up from just 0.5% the previous week.
In Denmark and India, BA.2 already accounts for around half of all sequenced cases, according to Gisaid.
Denmark’s Statens Serum Institut said on Wednesday that preliminary calculations indicated that BA.2 had a 50% transmission advantage over the original Omicron variant, BA.1, but was no longer likely to lead to hospitalization.
However, UKHSA data, released on Thursday, revealed the vaccines may be slightly more effective against the Omicron subtype than the original.
Booster injections were 63% effective against symptomatic BA.1 infection, compared to 70% against BA.2, at least two weeks after dosing. But data on BA.2 is limited, so estimates are less certain.
Spector predicted that infections would “stay high through spring.” “It is clear that Covid and its new variants will continue to impact our daily lives for some time to come,” he added.
Meanwhile, new data from NHS England released on Thursday revealed that staffing shortages in hospitals caused by the Omicron wave were continuing to narrow.
Around 23,770 staff were absent due to Covid disease or isolation in England’s 137 acute hospital trusts as of January 23, a decrease of 53% from the peak of almost 50,000 absences recorded at the beginning of January. In total, around 68,000 NHS staff were absent on January 23 for all reasons.
Matthew Taylor, chief executive of the NHS Confederation, which represents organizations in the health sector, said the improvement in staff sickness rates was “encouraging”. However, he said the NHS was still “under real pressure” due to “very full” hospital wards.