Hospital figures have been steadily rising over the last few months following the third wave of coronavirus infections, which began at the end of May.
Despite numbers levelling off in recent weeks, hospitalisations have started to climb again over the past few days, with a total of 5,514 patients in hospital with Covid-19 on 18 August.
This figure is up nine per cent from the previous week and is the highest number since 16 March, NHS England figures show.
The increase comes as new coronavirus cases have also started to rise again, with many becoming ill enough to require hospital care.
Prof Openshaw, a member of the New and Emerging Respiratory Virus Threats Advisory Group (Nervtag) which advises the government, has said that the current high case numbers are “very worrying”, particularly with winter fast approaching.
A booster vaccine programme is being considered in an effort to offer maximum protection for the most vulnerable people heading into the colder months, although an official decision on the rollout is yet to be made.
Professor Openshaw said: “I think we’re all really anxious about what’s going to happen once we return to normality.”
“We’re going into the winter with really very high levels of infection out there in the community and we just don’t really know what’s going to happen.”
NHS England figures show that London, the combined region of north-east England and Yorkshire, and the Midlands all currently have more than 1,000 patients in hospital with Covid-19 - marking the highest number since mid-March.
All regions are also recording week-on-week rises for patient admissions, with the south-east of England seeing the biggest rise at 18 per cent.
Listed are the areas which currently have the most patients in hospital with Covid-19, based on the latest figures from NHS England up to 17 August. Images are for illustrative purposes only.