Scientific government officials say the daily number of positive cases is on course to surpass the highest peak of the pandemic within a matter of weeks, with both the omicron and delta variants circulating alongside one another to fuel a swift wave of infections.
Ahead of this expected surge and a feared subsequent rise in admissions, NHS leaders have warned there is already “huge amounts of pressure” on hospitals. The risk of doctors and nurses catching omicron and being forced out of work is also adding to growing “nervousness” in the health service.
It is understood health officials in Whitehall are becoming increasingly worried by the emerging data on omicron, as the UK recorded 45,691 new Covid cases on Tuesday – a 15 per cent increase on last week’s figure.
A total of 437 omicron infections have been detected to date, but experts believe this figure to be closer to 2,000, with cases of the variant suspected to be doubling every day.
Prime minister Boris Johnson has told ministers that “early indications” suggest omicron is more transmissible than delta, which is set to be eventually displaced in the UK by the new variant.
It is unclear to what extent omicron is capable of evading the body’s immune response, or the severity of disease it causes, but growing belief that the UK could experience a sudden rise in cases ahead of Christmas has sparked alarm among health leaders.
Chris Hopson, chief executive of NHS Providers, said “there is a high degree of nervousness” around the projections for winter and how the health service will cope with any surge in hospitalisations caused by omicron.
He said that even if the symptoms of the variant “might not be that serious, if you get large numbers of people infected with this, having a very small subset of a large number is still quite significant extra pressure”.
Modelling by Professor Christina Pagel, director of the Clinical Operational Research Unit at University College London, suggests that England could be reporting 90,000 cases a day by Christmas – a combination of infections driven by the delta and omicron variants.
One member of Sage said it was “plausible” that this figure could be reached, but acknowledged it was a “worst-case” scenario, while Meaghan Kall, an epidemiologist at the UK Health Security Agency (UKHSA), said this projection could be “slightly optimistic”.
However, experts from the Scientific Pandemic Influenza Group on Modelling (SPI-M), a sub-committee of Sage, have insisted it is “really hard” to predict the size of the coming winter wave.
“It is likely that we will see omicron continue to increase, but the speed of that increase is uncertain,” said Professor Graham Medley, chair of SPI-M. “It has been rapid in the past week, but some of this might be due to active case finding and preferential testing.”
Another member, who asked to remain anonymous, said there was uncertainty surrounding the suggestion that delta and omicron would co-circulate for long, adding that it was likely that the former would displace the latter “once its prevalence is high enough”.
The prospect of reaching “90,000 cases does seem extremely pessimistic,” they said.
Concern around omicron comes amid a recent increase in hospital admissions in certain age groups and regions of England – a consequence of the country’s pre-existing delta caseload.
The rate of hospitalisations in the over-85s has risen by nearly 10 per cent in the last two weeks, according to the latest data up to 4 December. For 18 to 64-year-olds, there has been a 17.4 per cent increase in admissions over the same period.
Regionally, admissions are still falling across the north of England, but rising sharply in London and the southeast.
Mr Hopson said other NHS leaders were becoming “nervous” over the recent uptick in hospitalisations and “what that might mean”.
Even without the prospect of further strain from omicron, the NHS remains under immense amounts of pressure, he added.
“When you talk to our chief execs, what they’re basically saying is that they are definitely under a significantly higher degree of pressure for this time of year than they’ve been at any point in the past,” Mr Hopson said.
“I think that’s a kind of combination of the 5,000 Covid patients in hospitals and then real pressure on the urgent and emergency care pathway. We’ve seen that, for example, with ambulance handover delays. We need to ensure we carry on with the elective backlog too.”
One senior source at an NHS trust in the Midlands said if cases do reach 90,000 a day, this could “translate into more people seeking medical help, more pressure on GPs, and in particular on A&E departments. This will be even more difficult to manage as they attempt to deal with the pressures and keep infected patients separated from those who are ill with other health issues.”
A chief executive of another trust said they have been asked to look at surging critical care for a peak in admissions in mid-January.
Professor Irene Petersen, an epidemiologist at UCL, said there are “still some uncertainties in terms of how much impact omicron may have on the NHS,” but warned that this “may only be half of the story”.
“We may need to ask questions about how to go about our daily life if 20 million people in the UK will get infected by omicron in the coming months,” as some modelling has estimated. “Who is going to keep shops, schools and restaurants open? What will we do when a lot of bus and train drivers are off with omicron?”
Mr Hopson said if the omicron variant is capable of easily evading the body’s immune defences, leading to high rates of reinfection in hospitals among vaccinated nurses and nurses, this could drive another rise in mass staff absences.
“The idea that we suddenly get a significant increase in sickness absence rates is again a real cause for concern,” he added.