Pope Francis continued his recovery from double pneumonia Sunday after doctors reported some positive news: After more than three weeks in the hospital, the 88-year-old pope is responding well to treatment and has shown a "gradual, slight improvement" in recent days.

In the early Sunday update, the Vatican said Francis was resting after a quiet night. For the fourth Sunday in a row, the pope will not appear for his weekly noon blessing, though the Vatican planned to distribute the text he would have delivered if he were well enough.

The Argentine pope, who has chronic lung disease and had part of one lung removed as a young man, has remained stable, with no fever and good oxygen levels in his blood for several days, doctors reported in a Vatican statement Saturday.

The doctors said that such stability "as a consequence testifies to a good response to therapy." It was the first time the doctors had reported that Francis was responding positively to the treatment for the complex lung infection that was diagnosed after he was hospitalized on Feb. 14.

But they kept his prognosis as "guarded," meaning he's not out of danger.

In his absence, the Vatican’s day-to-day operations continued alongside celebrations of its Holy Year, the once-every-quarter-century Jubilee that brings millions of pilgrims to Rome. On Sunday, Canadian Cardinal Michael Czerny, who is close to Francis, celebrates the Holy Year Mass for volunteers that Francis was supposed to have celebrated.

Francis has been using high flows of supplemental oxygen to help him breathe during the day and a noninvasive mechanical ventilation mask at night.

Francis was hospitalized Feb. 14 for what was then just a bad case of bronchitis. The infection progressed into a complex respiratory tract infection and double pneumonia that has sidelined Francis for the longest period of his 12-year papacy and raised questions about the future.