Expect another Omicron wave in early summer, Sage says

Scientists advising the government have predicted there will be a fresh wave of Omicron cases in the early summer as people resume social activities and immunity wanes.

But experts on the Scientific Advisory Group for Emergencies (Sage) said they were increasingly confident that the worst case scenarios for the current wave are very unlikely to occur, with the latest modelling suggesting a peak of fewer than 4,000 hospitalisations each day.

Things have turned out better than some anticipated due to the lower intrinsic severity of Omicron compared with Delta and because vaccines have held up well against severe illness.

The size and timing of the next peak “cannot be predicted with any certainty”, according to the team at the University of Warwick. Modelling gave projections ranging from fewer than 1,000 admissions each day in the next wave to about 2,000 each day, for the scenario where plan B restrictions remain in place until the end of January and are followed by a gradual return to socialising.

However, uncertainty about factors including severity of Omicron, how long people typically take to become infectious, cross-immunity with other variants and how behaviour will change, makes it difficult to predict hospital admissions, the scientists said.

Scientists may have also overestimated the growth advantage of Omicron over Delta, the latest documents suggest, due to Omicron apparently having a shorter generation time (the average time between someone being infected, and that person infecting others). This suggests that the staggering rate at which Omicron cases took off could have been partly due to shorter generation time as well as because the strain is more infectious. Once this is factored in, a lower peak is predicted that is more consistent with current rates of hospitalisation, with 2,423 people admitted on Thursday.

However, at the 7 January meeting, scientists suggested that hospitals could remain under pressure for some time because prevalence in older people is high and growing rapidly, with hospital admissions expected to peak this month.

“It remains likely based on the scenarios that hospital admissions in England will remain high for some time as a result of the very high number of infections and the continued risk of hospitalisation for the elderly and unvaccinated adults in particular,” Sage scientists advised.


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