Boris Johnson admitted to hospital for tests. He has previously tested positive for coronavirus

“The Prime Minister thanks NHS staff for all of their incredible hard work and urges the public to continue to follow the Government’s advice to stay at home, protect the NHS and save lives,” it added.

CNN Medical Analyst Dr. Kent Sepkowitz, a physician at Memorial Sloan Kettering in New York and professor of medicine at Weill Cornell Medical College, said hospital visits could be necessary for testing like a CT scan of the chest or sophisticated bloodwork.

A hospital-grade test of blood oxygen could show “several more variables of lung function and might indicate whether he is just fatigued and spent, or actually in some danger,” Sepkowitz said.

Several of the people around Johnson have also tested positive or experienced symptoms that strongly suggest a coronavirus infection. His pregnant partner, Carrie Symonds, has also experienced Covid-19 symptoms, and said over the weekend that she is “on the mend.”

“I’ve spent the past week in bed with the main symptoms of Coronavirus. I haven’t needed to be tested and, after seven days of rest, I feel stronger and I’m on the mend,” she tweeted.

Johnson’s secretary of state for health, Matt Hancock said on March 27 he had the virus, and chief medical officer, Chris Whitty announced that he would begin self-isolation after displaying Covid-19 symptoms.

Johnson was a late convert to the strict social-distancing measures now in place in the UK. Only a few weeks ago, the Prime Minister boasted of shaking the hands of coronavirus patients in hospital. At that time, the UK faced criticism for a more cautious approach to the restrictive measures adopted by its European neighbors. It is now racing to catch up in terms of testing and social distancing.