Rome (CNN) -- Pope Francis is responding "positively" to medical treatment for pneumonia, according to the Vatican, a week after the 88-year-old pontiff was hospitalized in Rome.

Francis, who received the Eucharist, "devoted himself to work activities" following a "slight" improvement in his condition, according to a statement from the Vatican on Thursday. The pope had oxygen to assist his breathing, the spokesperson said, adding that his heart is holding up well and he has no fever.

The pontiff was admitted to Agostino Gemelli Polyclinic in the Italian capital on February 14, and initially underwent tests for a respiratory tract infection. He was subsequently diagnosed with pneumonia in both lungs after a later CT scan.

Francis, who is from Argentina, has a vulnerability to respiratory infections. As a young man, he suffered a severe bout of pneumonia that led to the removal of part of one lung.

In 2021, doctors also surgically removed part of his colon in relation to diverticulitis, which can cause inflammation or infection of the colon. He was hospitalized with bronchitis in 2023, and in recent months has had two falls where he bruised his chin and hurt his arm which was put into a sling.

Friday marks a week since he was admitted to the Gemelli hospital and is the third-longest time he has spent in hospital since his election as pope.

His doctors have advised "complete rest" for the pope, whose public events have been canceled until at least Saturday.

Even so, he has continued to do some work, including on the first two days of hospitalization holding his daily phone call to Rev. Gabriel Romanelli and his assistant, Father Yusuf Asad, in Gaza City, northern Gaza. They have been in frequent contact since Israel launched its bombing campaign and siege on the enclave, following the October 7 Hamas-led attacks.

Francis has also been signing off decisions in the clinic, Vatican spokesperson Matteo Bruni told CNN. Until now, only his "closest collaborators" have visited him, the Vatican spokesperson told reporters. On Wednesday, Italy's Prime Minister Giorgia Meloni visited him for 20 minutes.

"We joked as always. He hasn't lost his proverbial sense of humor," the prime minister said in a statement.

Outside the capital, worshipers have gathered in candle-lit churches - from Argentina to the Vatican - to pray for Francis' steady recovery.

"We always put him in our intentions," Rodomina Valdez, a 45-year-old Argentinian in the Metropolitan Cathedral, in the capital Buenos Aires, told Reuters on Wednesday. "But what we can do is put him in our prayers and offer fasting or in any case, some penance."

Just outside St. Peter's Basilica, at the Vatican, a German tourist, Klaus, said he hoped the pope "will have many strong years left in him." And back at the Agostino Gemelli Polyclinic, in Rome, letters and drawings made by children in the oncology department showed colorful illustrations and messages wishing him well.

"I hope he gets well soon and that he can get back to his role," Gaetano Bavagnini, a Rome resident, said. "He is an extraordinary man and an extraordinary pope."

The-CNN-Wire

™ & © 2025 Cable News Network, Inc., a Warner Bros. Discovery Company. All rights reserved.

CNN's Sana Noor Haq and Billy Stockwell contributed reporting.