LONDON and ROME — As Pope Francis continued to show “some” improvement in his lab tests, the pontiff remained hospitalized with a respiratory tract infection on Sunday, according to the Vatican.

Matteo Bruni, the director of the Vatican press room, told reporters on Sunday that the pope had his second consecutive restful night after being admitted to the hospital on Friday.

“Pope Francis had a tranquil night. He slept well, had breakfast and read a few papers, as usual,” Bruni said.

On Saturday, the Vatican said the pope “rested all night” Friday and had no fever on Saturday morning. His treatment has been slightly modified based on further “microbiological findings,” according to the Vatican.

The Vatican added, “To facilitate his recovery, the medical staff prescribed absolute rest.”

At the start of Sunday morning’s Jubilee Mass for Artists and the World of Culture at St. Peter’s Basilica, Cardinal Tolentino de Mendonca filled in for the pope and told worshippers, “Our first thought goes to Pope Francis. We pray for his health; we give thanks for the vision and support that he always offers us.”

The cardinal read from a text of the pope’s prepared homily for this Mass, which he said the pontiff wanted to read during the Mass.

“Today in the Vatican the Eucharist was celebrated, dedicated in particular to the artists who have come from various parts of the world to experience the Jubilee days,” the cardinal said, relaying the pope’s words. “I thank the Dicastery for Culture and Education for the preparation of this appointment, which reminds us of the importance of art as a universal language that spreads beauty and unites peoples, contributing to bringing harmony into the world and silencing every cry of war.”

Thanking the artists participating in the service, Francis added via the prepared homily, “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.”

“Thank you for the affection, prayer and closeness with which you are accompanying me in these days, and I would like to thank the doctors and health care workers in this hospital for their care: they do such a valuable and tiring job, let us support them with prayer,” the pope wrote.

The pope, according to the cardinal, asked everyone to continue to “pray for peace in tormented Ukraine, Palestine, Israel and all the Middle East, Myanmar, Kivu and Sudan.”

The pope was admitted to a hospital on Friday for “necessary tests” and to continue his ongoing bronchitis treatment, the Vatican said.

Medical tests are expected to continue over the weekend, Italian media reported.

“Pope Francis has been informed of the many messages of closeness and affection he has received and expresses his gratitude, as well as asking for continued prayers,” the Vatican added.

ANSA, the Italian news agency, reported that “several sources” revealed the pope had arrived on Friday at Gemelli Hospital very fatigued due to difficulty in breathing related to an excess of phlegm and that the treatment he was undergoing at home had not yielded the expected results.

However, there is optimism at the Vatican about the new medical treatment started on Friday immediately after tests established that the pontiff was suffering from an infection of the respiratory tract, according to ANSA.