Coronavirus: Anyone with cold or flu symptoms could be asked to stay home

Anyone with cold, flu or a fever is likely to be asked to stay at home in self-isolation before too long, England's chief medical officer has said.

Professor Chris Whitty said the number of cases in the UK is going up and pointed to tighter measures aimed at protecting the public, particularly the vulnerable and elderly.

It comes as Prime Minister Boris Johnson told reporters the UK will almost certainly move to the delay phase of tackling coronavirus.

As of 9am on Monday, 319 people have tested positive for Covid-19 in the UK, up from 273 at the same point on Sunday, while five people have died in British hospitals.

The latest patient was in their seventies and was unwell with a number of significant and long-term health conditions. They died at St Helier Hospital.

During a London press conference, Prof Whitty said: "We are expecting the numbers to increase initially slowly but really quite fast after a while and we have to catch it before the upswing begins.

"We are now very close to the time, probably within the next 10 to 14 days, when the modelling would imply we should move to a situation where everybody with even minor respiratory tract infections or a fever should be self-isolating for a period of seven days."

Mr Johnson said there was "no hiding from the fact that the coronavirus outbreak will present significant challenges for the UK just as it does in other countries".

"But if we continue to look out for one another, to pull together in a united and national effort, I have no doubt that we can and will rise to that challenge," he added.

The PM praised the "truly brilliant NHS" and its staff but suggested the elderly and vulnerable could be asked to stay home in the near future.

He said: "We will set out further steps in the days and weeks ahead to help people protect themselves, their family and in particularly the elderly and vulnerable."

The UK remains in the "contain" phase of the response to coronavirus "but watching what is happening around the world, our scientists think containment is extremely unlikely to work on its own", he continued.

"That is why we are making extensive preparations for a move to the delay phase.

"We are preparing various actions to slow the spread of this disease in order to reduce the strain it places on the NHS.

"The more we can delay the peak of the spread to the summer, the better the NHS will be able to manage."

The PM also reiterated that people should continue to wash their hands for 20 seconds each time with soap and water.

Sir Patrick Vallance, the Government's chief scientific adviser, told reporters: "Some of them (the measures they are looking at) are about protecting all of us – it is about us being good citizens to protect each other. Some of them are about protecting ourselves. It is important we do both."

Prof Whitty said anybody with a serious enough respiratory infection that they need hospital treatment will now be tested and counted in coronavirus figures, alongside those in intensive care as at present.

He said it was important not to ask people to start practising social distancing measures too soon, saying: "What we are moving now to is a phase when we will be having to ask members of the general public to do different things than they would normally do."

He stressed the importance of timing because "anything we do, we have got to be able to sustain" throughout the peak of the outbreak.

"There is a risk if we go too early people will understandably get fatigued and it will be difficult to sustain this over time," he said.

"So getting the timing right is absolutely critical to making this work."

The comments come as Tedros Ghebreyesus, director of the World Health Organisation (WHO), told reporters the global spread of Covid-19 made a pandemic threat "very real".

He said: "Now that the virus has a foothold in so many countries, the threat of a pandemic has become very real.

"But it would be the first pandemic in history that could be controlled. The bottom line is that we're not at the mercy of the virus."

Earlier, Prof Whitty said the fourth patient with Covid-19 to die was in their seventies with underlying health conditions and was being treated at the Royal Wolverhampton Hospital. They are thought to have contracted it in the UK.

In other developments:

– On another bleak day for the global markets, trading was halted on the New York Stock Exchange for 15 minutes after the S&P 500 index fell 7% due to a collapse in the oil price and fears over Covid-19

– Transport for London confirmed a staff member had tested positive

– A pupil at Rugby Free Secondary School in Warwickshire is self-isolating at home after being diagnosed with Covid-19

– The House of Commons and House of Lords' ruling bodies said there were "no plans to suspend Parliament" but the response to the outbreak was under constant review

– University Hospital Southampton closed its surgical high-dependency unit to new admissions after a staff member tested positive

– Public Health England (PHE) will roll out enhanced monitoring of flights from all parts of Italy from Wednesday

– The France vs Ireland Six Nations rugby match due to be held in Paris on Saturday was postponed on the advice of national authorities

– Culture Secretary Oliver Dowden said cancelling sports events and shutting museums and galleries due to coronavirus would be "premature"

– All St Patrick's Day parades in the Republic of Ireland are to be cancelled in a bid to stop the spread of Covid-19.

At the weekend, Italy imposed restrictions on around 16 million people for nearly a month in a bid to stop the spread of the disease there.

Italy has the highest number of confirmed cases outside of China at 7,375, and its death toll stands at 366.

The Foreign Office is in contact with around 142 British nationals on the Grand Princess cruise ship, which is due to start disembarkation of guests at the Port of Oakland, California, on Monday.

The FCO said it was "working intensively" with US authorities to arrange a flight for UK citizens who are then likely to be taken into quarantine.