COVID related admissions to hospitals have surged in England in the past week amid fears the country is at the start of a new winter wave.
The seven-day average for new admissions with COVID is up 48% over the last week for which full data is available, rising from 574 on 16 September to 847 on 23 September.
According to analysis by the COVID-19 Actuaries Response Group, this equates to R rate of 1.2, the highest seen in 2022.
The biggest increases in COVID admissions in a week have been seen in the South East and Midlands, up 64% and 58% respectively.
COVID hospital bed occupancy is up 37% in the last seven days.
The COVID-19 Actuaries Response Group said the increase was being driven by people getting COVID while in hospital and suggested this could be a consequence of routine testing on admission being reduced, allowing for the virus to spread freely in hospitals.
The group noted deaths in English hospitals remained flat for the time being.
Professor Tim Spector, co-founder of the Zoe study, said: "It’s clear we’re now seeing an autumn wave of COVID-19, combined with increases in hospital admissions.
"With rates on the rise, especially in the vulnerable elderly age groups, the impact on hospitalisations could be higher.
"However, the youngest age group are showing possible early signs of case numbers slowing. Children tend to be a leader of infection trends, so if this continues next week it is possible that the COVID wave might not be as bad as previously predicted."
Dr Zubaida Haque said the rise was inevitable with no mitigations in place and waning vaccine immunity.
Dr Mary Ramsay, UK Health Security Agency (UKHSA) director of public health programmes, said it was "clear now that we are seeing an increase" in levels of COVID-19.
"Cases have started to climb and hospitalisations are increasing in the oldest age groups. In the coming weeks, we expect a double threat of low immunity and widely circulating flu and COVID-19, creating an unpredictable winter and additional pressure on health services," she said.
All people aged 65 and over are eligible for the booster, providing they had their last jab at least three months ago.
More than a quarter of over-75s in England have now received an autumn booster dose.
Doses are also available to frontline health and care workers, pregnant women and people with weakened immune systems.
The booster is intended to increase protection against serious illness during the next waves of the virus and will eventually be offered to everyone aged 50 and over.