There have also been some suggestions Mr Johnson could have pneumonia, however, there has been no official confirmation of this.
Former chair of the BMA GP committee, Dr Laurence Buckman said earlier today Mr Johnson could have pneumonia.
Asked whether the Prime Minister’s admission to hospital was because of the pneumonia, which can be triggered by coronavirus, Dr Buckman replied: “That’s the obvious thing to go looking for.
“But they will have to turn over every stone until they find the reason why he’s got a persistent fever.
“It can’t just be single COVID-19 anymore. There has to be a reason for that, whatever it is.”