Further coronavirus waves cannot be ruled out and there is a lot of uncertainty about how the pandemic will pan out into the first half of next year, Government scientists have said.
Optimistic projections from Imperial College London suggest current levels of protection in the population, combined with booster vaccines, should maintain the epidemic at levels similar to, or lower than, those currently observed.
However, the more pessimistic projections around people mixing, or underlying assumptions on how long immunity lasts, project a substantial wave of total infections, hospitalisations and deaths, totalling 9,900 deaths by the end of March next year.
The projections were made in papers released by the Scientific Advisory Group for Emergencies (Sage) on Friday.
A University of Warwick paper considers transmission and the virus until June next year, looking at the action of waning vaccine efficacy and boosters.
The scientists say further waves of infection cannot be excluded and there remains considerable uncertainty about the long-term dynamics.
Most of the scenarios considered project a slow decline in hospital admissions and deaths throughout the rest of 2021.
But the paper also sets out: “A continuation in the observed decline in vaccine efficacy can generate very large-scale waves of hospital admissions in the next four to eight months, which can be further exacerbated by high levels of seasonal forcing.
“These could be tempered by either giving boosters to younger age groups, hence pushing the population closer to herd immunity, or by giving additional boosters to older age groups to maintain high efficacy.”
According to the authors, vaccine efficacies that remain at a high asymptotic level of protection result in a continual decline in hospital admissions between now and June 2022.
They add: “A more gradual return to pre-Covid mixing patterns pushes the epidemic waves to later in 2022.”
The researchers highlight a number of uncertainties, including the waning of vaccine efficacy, the behaviour of the population, and the limited information on seasonality.