The pope’s agenda was not made public this morning, as it usually is on a Friday.
The Vatican press office didn’t provide any further details on the Pope’s illness.
The Vatican Secretary of State, Cardinal Pietro Parolin, said Francis was ‘tired’ after a ‘very intense day’ on Thursday, according to Italian news agency ANSA.
Vatican spokesman Matteo Bruni said: ‘Due to a feverish state, Pope Francis did not receive an audience this morning.’
Francis has suffered increasing health issues over the past year, from persistent knee pain to his recent hospital stay for bronchitis.
Pope Francis spent five days in a Rome hospital at the end of March for bronchitis.
He recovered quickly from the illness after taking antibiotics and was able to go on a three-day trip to Hungary at the end of April.
In late March, Francis was admitted to hospital in Rome after having breathing difficulties, and stayed for three nights. He was treated with antibiotics for bronchitis.
As he left the Gemelli Hospital on April 1, the pope smiled and joked with well-wishers, quipping: “I am still alive!”
For about a year, the pope has had to rely on a wheelchair due to recurring pain in his knee that he has said cannot be treated through surgery.
Asked about his health in an interview with US Spanish-language network Telemundo broadcast on Thursday, Francis said it was ‘much better’.
‘I can walk now. My knee has been mending. I could hardly walk beforehand, now I can. Some days are more painful than others, like today,’ the pope said.
Francis added that doctors had caught his bronchitis infection just in time.
‘If we’d waited a few more hours, it would’ve been much more serious. But I was out (of the hospital) in four days,’ he said.