British health authorities say they have high confidence that the Omicron coronavirus variant causes a low severity of disease in adults.
The UK Health Security Agency (UKHSA) made the claims in an updated risk assessment of Omicron, detailing an analysis of vaccine efficacy, sub-lineage and symptoms.
“There is now high confidence that the Omicron variant causes low severity of disease in adults,” UKHSA said.
It said vaccines remained effective against the variant and data showed that a booster dose was associated with a 74 per cent reduced risk of admission to hospital.
However, it said children under 1 are proportionally more likely to be admitted to hospital with Omicron than older children.
Of children admitted to hospital with Covid-19 in the past four weeks, 42 per cent were under the age of 1, compared with about 30 per cent in previous waves.
“We’ll be undertaking further analysis to investigate the small rise in the number of children admitted to hospital,” said Susan Hopkins, chief medical adviser at UKHSA.
“Early data show that young children who are hospitalised experience mild illness and are discharged after short stays in hospital.”
On Friday, the UK reported more than 99,000 new lab-confirmed cases of coronavirus, the lowest figure since December 22.
Deaths from the disease continue to rise, however, with an additional 270 people reported to have died from Covid-19 within 28 days of a positive test.
Further analysis showed that tens of thousands of new cases of coronavirus in the UK are not being included in official daily figures.
An average of 114,600 new cases were recorded each day in the week ending December 23, the government's Covid-19 dashboard showed.
But the true figure might have been more than three times that number, new estimates published by the Office for National Statistics (ONS) showed.
This means more than 1.5 million new cases of coronavirus could have been left out of official figures in the week before Christmas.
The government's daily figures only count those people who have reported themselves as having tested positive for the virus.
The ONS survey circumvents this issue by sampling the same number of people in the UK every week, regardless of whether they know they have Covid-19 or have reported a positive result.