Dr Jim McMenamin, the national Covid-19 incident director for Public Health Scotland, labelled the findings a “qualified good news story”, but warned that it was “important we don’t get ahead of ourselves”.
Professor Aziz Sheikh, who led the study, said omicron being inherently less severe was the “most likely explanation” of the results.
“This data and the South African study point in the same direction which is encouraging,” he said.
Another cause for hope in the UK is that omicron has not yet penetrated the elderly population in large numbers.
The vast majority of confirmed cases are still in younger, more mobile groups who, by dint of their age, are much less likely to end up in hospital.
Past experience might suggest it is only a matter of time before the virus works its way up to the age bands, but there is also reason to hope the impact of boosters will keep it at bay.
Over 80 per cent of those above 55-years-old who were double jabbed have now had their booster, rising to over 90 per cent for those 65 to 79.
“It’s a fantastic achievement already, with the rate in England doubling to 5 million boosters in the week following the PM’s announcement of the acceleration”, said John Roberts of the Covid-19 Actuaries Response Group.
Of course, we do much more intergenerational mixing at Christmas than at any other time of year and that could provide the virus with a rapid means to move up the age range.
Many epidemiologists are worried about what the mixing of the next few days might bring, but public caution combined with boosters could yet still see the elderly protected, some say.
On Thursday, the UK Health Security Agency will publish an updated technical assessment of omicron, and it is expected to include a “firmer” (but not definitive) analysis of omicron’s severity when compared to delta.
Feeding into this will be new data from the Imperial College modelling team, headed by Prof Neil Ferguson.
Last Friday, Imperial said it could see no difference in the severity of omicron cases in England compared to delta but at that point they were working from just 24 omicron hospital admissions.
Yesterday, however, it provided a third reason to be cheerful. Compared with Delta, people with PCR-confirmed Omicron infection were 15 to 20 per cent less likely to require any hospitalisation on average, it said.
Better still, they were approximately 40 to 45 per cent less likely to require hospitalisation resulting in a stay of one or more nights.
Professor Neil Ferguson, who led the study, described the results as “clearly good news to a degree”.
He added: “Our analysis shows evidence of a moderate reduction in the risk of hospitalisation associated with the Omicron variant compared with the Delta variant. However, this appears to be offset by the reduced efficacy of vaccines against infection with the Omicron variant”.
