The UK's Chief Medical Officers (CMOs) have warned of "multiple challenges" and "a great deal of pressure" from the Omicron variant in the year ahead.
Figures from NHS England show that 1,904 people were in hospital in London with Covid-19 as of December 21, the highest number since March 2 and is up 41% from a week earlier.
Across England, 6,902 patients were in hospital with Covid-19 on December 21 - the highest number since November 10 and up 7% week-on-week.
READ MORE: Seven Omicron symptoms you should never ignore
The CMOs also praised health service staff who have worked on the frontlines during the pandemic.
They added the work of health staff has "substantially reduced the impact of this pandemic on the lives of the UK public" but the fast-spreading Omicron variant of the coronavirus, along with the Delta version that has already struck, means the profession will still be tested.
In a joint online statement, the CMOs said: "Your tireless work has substantially reduced the impact of this pandemic on the lives of the UK public.
"We are well aware of the toll this has had on many members of the profession, and the support colleagues have continue to give to one another in difficult times has been essential.
"The collective effort on behalf of our patients and the wider public has been remarkable.
"We were all hoping that Covid would be less dominant across the health service as we move into the New Year, but the Omicron variant is clearly going to put a great deal of pressure on health services and on all health professionals.
"We can all see the concerning numbers of Omicron-infected people rising very rapidly, some of whom will become seriously ill and need medical care.
"This is on top of existing Delta patients, the backlog of work from the previous Covid wave, normal health service work and other winter pressures."
Vaccination, and booster jabs in particular, as the best counter-measure against Omicron and praised the whole medical profession in primary and secondary care for the "rapid and effective" way it was working to deal with this new threat.
In a personal note introducing the post, Prof Chris Whitty added: "After a very difficult year for the health system, the UK CMOs want to express our enduring thanks to, and great pride in, the health professions across the country.
"We face yet more hard weeks ahead. Look out for one another as we continue to care for the public."
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