Pope Francis has shown the onset of bilateral pneumonia and his respiratory infection "continues to present a complex picture," the Vatican has said.
The 88-year-old pontiff has been suffering from a respiratory infection for more than a week and was admitted to Rome's Gemelli hospital on 14 February.
Earlier, the Vatican conformed that the pope will not take part in this weekend's Holy Year events.
A papal mass scheduled for Sunday will still take place, but will be led instead by a senior Vatican official, it added.
The Vatican said the pope had a peaceful night last night and ate breakfast this morning, an indication that he is not on a respirator and is well enough to digest food.

The Vatican said yesterday that doctors had changed the pope's drug therapy for the second time during his hospital stay to tackle a "complex clinical situation".
They described it is a "polymicrobial infection of the respiratory tract".
Doctors say polymicrobial diseases can be caused by a mix of viruses, bacteria and fungi.
Pope Francis, who has been pontiff since 2013, has had influenza and other health problems several times over the past two years.
As a young adult he developed pleurisy and had part of one lung removed, and in recent times has been prone to lung infections.
Despite his health troubles, Francis remains a very active pontiff, with a busy weekly schedule and regular overseas trips.
In September 2024, he completed a four-nation Asia-Pacific tour, the longest of his papacy by duration and distance.
He followed Sunday's mass on television from hospital and sent a written address for the Angelus.
"I would have liked to be among you but, as you know, I am here at the Gemelli hospital because I still need some treatment for my bronchitis," Francis wrote.
The Argentine Jesuit has left open the option of resigning if he became unable to carry out his duties.
His predecessor, Benedict XVI, stunned the world in 2013 by becoming the first pope since the Middle Ages to step down, citing his ailing health.