A person with Omicron is “50 to 70% less likely to be admitted to hospital” than a person with the Delta strain, early analysis for the UK government has said.
Someone with the Omicron variant is also 31% to 45% less likely to attend A&E compared to Delta, the UK Health Security Agency said.
UKHSA’s chief executive Dr Jenny Harries hailed the data as an “encouragingly early signal” that people who contract Omicron “may be” at lower risk.
But she also warned it was “early data and more research is required to confirm these findings”.
It is thought there are several caveats - including that the analysis of hospitalisations was only based on about 100 cases. The real range could be more like 30% to 70%, UKHSA officials believe.
Dr Harries warned the more transmissible strain could still lead to “a significant number of people” entering hospital - even if it’s milder.
The report was one of two hotly-awaited pieces of analysis on how severe the Omicron strain is compared to Delta, which was previously the dominant UK variant.
The other, from Imperial College London, said Omicron cases were around 15% less likely than Delta cases to attend hospital - and 40% less likely to spend a night or more in hospital.
It is thought Imperial’s data is less optimistic because while UKHSA adjusted for age, sex, ethnicity and vaccination status, Imperial also pulled out details on whether people had been previously infected with Covid.
Imperial also used a much larger sample of people.
It is difficult to compare serious illness in Omicron and Delta cases, because Omicron is more likely to infect vaccinated people - who in turn have better protection against serious disease.
Most Omicron cases are also being driven by under-40s, who are less likely to become seriously ill.
