Johnson, 55, was first admitted to St Thomas’ Hospital in London on Sunday evening for what he said were “routine tests,” adding that was in “good spirits.”
But the dramatic change in the leader’s health has shocked the nation, with politicians from his party and the opposition voicing their support for the leader as the country battles a widespread coronavirus outbreak.
“Over the course of this afternoon, the condition of the Prime Minister has worsened and, on the advice of his medical team, he has been moved to the Intensive Care Unit at the hospital,” a Downing Street spokesperson said.
According to Downing Street officials, Johnson remains conscious and has been moved to the intensive care unit as a precaution, in case he requires ventilation.
The Prime Minister’s spokesperson had said earlier on Monday that Johnson spent a “comfortable” night in hospital, but would not comment on reports Johnson was given oxygen. Officials are no longer describing his symptoms as mild.
Downing Street on Monday said that Johnson has asked Foreign Secretary Dominic Raab, who is the First Secretary of State and the most senior Cabinet minister, to deputize for him where necessary.
Raab chaired Monday’s regular morning coronavirus briefing and made a televised statement saying that the government will continue Johnson’s direction in responding to the outbreak.
“The government’s business will continue and the Prime Minister is in safe hands with a brilliant team at St Thomas’s hospital. And the focus of the government will continue to be on making sure that the Prime Minister’s direction, all the plans for making sure that we can defeat coronavirus and can pull the country through this challenge, will be taken forward,” he said.
He added there was an “incredibly strong team spirit” in government behind the Prime Minister.
Johnson was moved to the intensive care unit at around 7 p.m., Downing Street said. The decision was made by the leader’s medical team after his condition worsened over the afternoon on Monday.
The United Kingdom passed a total death toll of more than 5,000 on Monday, according to Johns Hopkins University, one of the world’s highest reported death tolls.
The government has been scrambling to implement widespread testing as evidence grows that people infected could be asymptomatic.
‘Together we will beat this,’ Johnson said
Johnson was hospitalized Sunday because he was still suffering coronavirus symptoms 10 days after testing positive for the virus.
The British leader announced on March 27 that he had been infected and was, at the time, suffering mild symptoms including a cough and fever.
At the time, he vowed to continue leading the nation’s response to the outbreak and hold meetings via video-conference, saying in a video: “Together we will beat this.”
The leader of the country’s House of Commons, Lindsay Hoyle, said Johnson’s admission to intensive care was “terrible news.”
“I know the thoughts and prayers of everyone across the House are with the Prime Minister and his family right now. We all wish him a speedy recovery.”
“All the country’s thoughts are with the Prime Minister and his family during this incredibly difficult time.”
Former Prime Minister Theresa May, who was replaced by Johnson in the country’s Brexit crisis, also sent her wishes to the leader on Twitter.
“My thoughts and prayers are with @BorisJohnson and his family as he continues to receive treatment in hospital. This horrific virus does not discriminate. Anyone can get it. Anyone can spread it. Please #StayHomeSaveLives,” May wrote.
In a post on Twitter, Johnson had said he was keeping in touch with his team and thanked staff at Britain’s National Health Service for taking care of him.
US President Donald Trump had expressed sympathy after Johnson was initially hospitalized, calling him “a strong man and a strong person.” In a news conference Sunday night, President Trump said: “I want to express our nation’s well wishes to Prime Minister Boris Johnson as he wages his own personal fight with the virus.”
“All Americans are praying for him. He’s a friend of mine, he’s a great gentleman and a great leader.”
Johnson’s pregnant partner, Carrie Symonds, has also experienced Covid-19 symptoms, and said over the weekend that she is “on the mend.”
Johnson’s secretary of state for health, Matt Hancock, also said on March 27 he had the virus, and the UK’s chief medical officer, Chris Whitty, announced that he would begin self-isolation after displaying symptoms.
The UK had faced criticism for its slow response to the coronavirus, with Johnson still shaking hands of patients with the virus in hospital just a few weeks ago.
CNN’s Lauren Kent, Nikki Carvajal, Susannah Cullinane and Mohammed Tawfeeq contributed reporting.