Video report by ITV News Correspondent Dan Rivers
Two further patients in England have tested positive for coronavirus, the Department of Health (DoH) said as experts warned of "social cost" if the virus intensifies.
The two patients have been transferred to specialist NHS infection centres after contracting the virus in Italy and Tenerife, according to England's chief medical officer Professor Chris Whitty.
There are currently 168 Britons in isolation at the H10 Costa Adeje Palace in Tenerife after an Italian doctor and his wife tested positive for the virus during their stay there.
The new cases bring the total number of people diagnosed with Covid-19 in the UK to 15. One of the cases is understood to be a parent from Burbage Primary School in Buxton, Derbyshire, who caught the virus while in Tenerife.
Parents were told the school would be closed on Thursday due to a "confirmed case of coronavirus amongst our parent population".
The school, which has 350 pupils, sent a message to parents via WhatsApp on Wednesday night saying the decision had been taken as a "precautionary measure and to enable a deep clean to be completed".
Buxton Medical Practice in Derbyshire, a two-minute drive from the school, urged patients not to attend on Thursday due to a confirmed case of coronavirus.
Health Secretary Matt Hancock answers a question from ITV News' Health Correspondent Emily Morgan about the Prime Minister's response to coronavirus.
Speaking on Thursday, Health Secretary Matt Hancock said the government was "doing everything reasonably possible to keep the public safe."
He told ITV News' Health Correspondent Emily Morgan he was chairing weekly COBRA meetings to discuss "cross-government" responses "to keep people safe."
Several other schools across the country were closed, while others have sent pupils home amid fears they may have been exposed to coronavirus during trips to northern Italy, including pupils at Prince George and Princess Charlotte's school.
Four pupils from St Thomas's Battersea School in south-west London were told to stay home amid concerns they may have the Covid-19 virus.
In a statement on Thursday, Professor Whitty said:“Two further patients in England have tested positive for COVID-19, bringing the total number of UK cases to 15.
“The virus was passed on in Italy and Tenerife and the patients have been transferred to specialist NHS infection centres in Royal Liverpool Hospital and the Royal Free Hospital, London.”
He added there could be a "social cost" if the virus intensifies which could lead to the reduction of mass gatherings and school closures for more than two months.
"One of the things that's really clear with this virus, much more so than flu, is that anything we do we're going to have to do for quite a long period of time, probably more than two months," Professor Whitty said.
"The implications of that are non-trivial, so we need to think that through carefully.
"This is something we face as really quite a serious problem for society potentially if this goes out of control. It may not but if it does globally then we may have to face that."
Italy, along with South Korea and Iran, has been particularly hard hit by the virus as new cases of Covid-19 outside of China are increasing faster than those inside the country for the first time.
Italy remains Europe's most deadly outbreak; 12 people have died there and, while the official number of cases in the country stands are 47, experts say in reality there could be more than a thousand cases. The Foreign Office has advised against all but essential travel to 10 towns in Lombardy and one in Veneto.
British traveller Paul Godfrey is awaiting test results after returning from a trip to Milan with symptoms.
He told ITV News he is "staying positive".
"Because it's been labelled as a coronavirus I think that people do tend to panic to think it's something worse than what ever anyone's ever had," Mr Godfrey said.
"But I just think if can follow stringent guidelines and look after yourself and you're fit and healthy you can get over these kind of things."
Meanwhile, officials denied there were any plans to evacuate the Britons at the hotel in Tenerife, instead arranging for written messages to be put under the doors of the rooms of British guests asking them to get in contact.
The Six Nations match between Ireland and Italy was postponed as Europe struggles to maintain the outbreak.
The sides had been scheduled to play in Dublin on March 7 but the Irish Rugby Football Union (IRFU) announced the fixture had been postponed.
The union said the decision to postpone the Six Nations rugby fixture against Italy was made following a meeting with Irish Health Minister Simon Harris.
Saudi Arabia is stopping pilgrims from entering the country to travel to some of the holiest sites in Islam over coronavirus fears.
The extraordinary decision by Saudi Arabia stops foreigners from reaching the holy city of Mecca - the birthplace of the Prophet Muhammad - and the Kaaba, the cube-shaped structure the world's 1.8 billion Muslims pray toward five times a day.
The decision also affected travel to the Prophet Muhammad's mosque and burial site in Medina.
Iran's Health Ministry spokesman says the new coronavirus has killed 26 people amid 245 confirmed cases in the country.
The United States, which has 60 cases, has not been spared the fear that has swept Asia, Europe and the Mideast.
President Donald Trump declared that the US was "very, very ready" for whatever threat the coronavirus brings, and he put Vice President Mike Pence in charge of overseeing the country's response.
Meanwhile, Japan has made the decision to close all primary and secondary schools for most of March from this weekend to curb the spread of the virus.