The 88-year-old pontiff is undergoing treatment at Rome's Gemelli Hospital, where he was admitted on February 14 after struggling with breathing difficulties for several days.
Vatican spokesman Matteo Bruni said in a brief update that the Pope had slept well and had breakfast while seated in an armchair.
The Pope's condition was stable and he had shown "slight improvement" in results from recent blood tests, the Vatican said in its latest medical statement.
Francis is suffering from double pneumonia, a serious infection that can inflame and scar both lungs and makes breathing more difficult.
The Vatican had said previously the Pope had a polymicrobial infection, which occurs when two or more micro-organisms are involved, adding that he would stay in hospital as long as necessary to tackle a "complex clinical situation".
A Vatican official, who did not wish to be named because he was not authorised to speak about the Pope's condition, said on Thursday that Francis was not on a ventilator and was breathing on his own.
The Pope was able to move around his hospital room, was taking some phone calls and was continuing to do some paperwork, the official said.
Francis received a visit on Wednesday from Italian Prime Minister Giorgia Meloni, his first known VIP visitor in hospital.
She said he was "alert and responsive".
The Pope joked with Meloni about some people betting on his death, Italian newspaper Corriere della Sera reported on Thursday.
"He hasn't lost his proverbial sense of humour," Meloni said in a statement.
The pontiff's latest illness is the latest in a long history of health problems he has suffered over the years.
No discharge date has been announced, and the Pope's scheduled events have been cancelled for the coming days.
Reuters and DPA
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