Sir Chris Whitty and Sir Patrick Vallance have warned that the UK is not out of the coronavirus pandemic and there may be more variants of the virus in the coming months and years.
Professor Whitty said that new variants could be more adept at vaccine-escape, similar to the recent Omicron variant.
He also added that new variants, which could be more severe than those we have already seen, could result in more people being hospitalised.
He said the number of people in hospital with Covid in the UK remains 'significant' and that this is still putting quite a lot of pressure on many hospitals.
He did add that rates 'have been going down steadily now for some weeks'.
Winters ahead Chris Whitty added could be 'tricky' - along with the impact of the flu virus as well as other new coronavirus cases.
The comments come almost two years on from the first ever daily coronavirus update, back in March of 2020 when the pandemic first hit.
The Monday night press conference was held to discuss the government’s new plans for the future and “living with Covid”.
Sir Vallance echoed the same point as Mr Whitty - warning that the UK is 'not yet out of it' and could not guarantee that future variants would be less severe than those we have already seen, including Delta and Omicron.
It comes following a statement in the House of Commons earlier on Monday, where the Prime Minister announced that all remaining legal Covid restrictions in England are to be scrapped.
In his address to MPs, Mr Johnson said the country was now "past the peak of the Omicron wave" and must learn to "live with Covid."
From Thursday (February 24), there will no longer be a legal requirement to self-isolate following a positive test.
Those who receive a positive Covid test will still be advised to stay at home for at least five days, but will not be obliged to under law under the plans subject to parliamentary approval.
Routine contact tracing will also end on Thursday, as will self-isolation payments and the legal obligation for individuals to tell their employers about their requirement to isolate.
But most vulnerable will continue to get free tests if they are symptomatic and others will be able to pay for them.
Staff and students will no longer be asked to undertake twice weekly asymptomatic testing from Tuesday, February 22.
Mr Johnson also told MPs that changes to statutory sick pay and employment support allowance designed to help people through the coronavirus pandemic will end on March 24.
Under the changes, free universal testing will also cease from April 1.
