Hospital Covid admissions from omicron could exceed second wave, study suggests

Even if omicron turns out to be just half as severe as delta, UK hospitalisations could exceed those seen at the peak of the second wave, according to new modelling.

By Paul Nuki, Global Health Security Editor 

The study, which has been presented to Sage and produced by the University of Warwick, has suggested that the NHS will only escape a re-run of last year if omicron turns out to be five to 10 times milder than other variants.

“Under these assumptions of no additional control [beyond Plan B], and even assuming omicron is just 10 per cent the severity of delta it is still highly likely that hospital admissions will peak above 1,500 per day,” said the authors.

“If we assume that omicron is as severe as delta [black line] then admissions will be an order of magnitude larger, peaking at around 27,000 admissions.”

There is strong evidence to suggest omicron is less severe than delta, but estimates as to how much less severe vary greatly.

Data from Scotland released last week suggested omicron is associated with a two thirds reduction in risk of hospitalisation when compared with delta.

‘Strong controls enacted early bring the greatest reduction in infections, hospital admissions and deaths’

A separate study by Imperial College London looking at early English data suggested people with PCR-confirmed omicron infection were 15 to 20 per cent less likely to require hospitalisation.

The Warwick modelling is not intended to predict what will happen over the next few months. Instead it is designed to inform ministers about the range of possibilities that may unfold.

The authors say that assuming the omicron is 100 per cent as severe as delta (black line on chart) represents a “reasonable worst case”.

They also caution that if the time it takes omicron to become symptomatic is shorter than with delta – as it is now strongly suspected – it would radically alter their results for the better.

“If the generation time of omicron was half that of delta, once the model is recalibrated… this would approximately halve the predicted peak outbreak sizes”, they said.

The modelling also looks at the impact of reimposing restrictions beyond Plan B and finds – unsurprisingly perhaps – that it brings the projections for cases, hospitalisations and deaths down significantly, albeit at a cost to the economy and peoples freedoms.

“Strong controls enacted early bring the greatest reduction in infections, hospital admissions and deaths during the first wave of omicron”, it says.

Ministers will have seen or had the message from the Warwick modelling conveyed to them before Christmas when it was decided to stick to the plan B measures only.

And most experts now agreed that implementing measures now would have a much diminished impact, given the intergenerational mixing that happened over Christmas.

Yet ministers will be watching the live data carefully.

There were a total of 11,452 people in hospital in England with Covid-19 as of 8am on Thursday, according to figures from NHS England.

This is up 61 per cent from a week earlier and is the highest number since February 26.

During the second wave of coronavirus, the number peaked at 34,336 on January 18.