England will continue with its Plan B Covid measures amid growing pressures on the NHS, Boris Johnson has said.
The prime minister said it would be "folly" to think the pandemic was over and pressure on hospitals would be "considerable" over the coming weeks.
However, he added the country was in a "much better position" than this time last year thanks to vaccinations.
The PM stressed Omicron looks less severe than other variants, despite it being "incredibly transmissible".
Speaking during a visit to a vaccination centre in Aylesbury, he said the "mixture of things we're doing at the moment" were the correct measures.
He said this included continuing with Plan B, which includes mask wearing in certain indoor settings and guidance to work from home where possible, ensuring it is taken "seriously" by people.
These measures are due to expire on 26 January, although they are expected to be reviewed on Wednesday.
BBC political correspondent Chris Mason said to expect the status quo to rumble on until the end of the month, when the picture should be clearer as to what impact Christmas and New Year mixing had.
On Monday, 157,758 new coronavirus cases were reported across England and Scotland, with data from Wales and Northern Ireland to be reported after the holiday weekend.
A further 42 deaths within 28 days of a positive coronavirus test were reported in England.
Mr Johnson added people should be "sensible" and take a rapid test before going to see people they do not usually meet, as well as getting their first, second and booster jabs.
"We've got to make sure we look after our NHS in any way that we can" he said, adding: "I appreciate the pressures that our hospitals are under."
'Remain cautious'
As NHS trusts warn of staffing pressures, Mr Johnson said the government was looking at what it could do to "move people into those areas that are particularly badly affected".
He said: "Looking at the pressures on the NHS in the next couple of weeks and maybe longer... looking at the numbers of people who are going to be going into hospital, it would be absolute folly to say that this thing is all over now bar the shouting.
"We've got to remain cautious, we've got to stick with plan B, we've got to get boosted."
Chris Hopson, chief executive of NHS Providers, which represents NHS trusts, said on Twitter it was "very clear" the NHS in the rest of the country was "now coming under the significant pressure London has been encountering".
