Pope Francis’ condition remains serious but has shown “slight improvement” as he continues treatment on his 11th day in Rome’s Gemelli Hospital, the Vatican said Monday evening.

The 88-year-old Pontiff is still receiving oxygen therapy through his nose, though at a slightly reduced flow and concentration, according to the Holy See Press Office.

Doctors reported no further episodes of respiratory distress following a “respiratory crisis” on Saturday. Some of the Pope’s laboratory tests have improved, and his “mild kidney insufficiency” remains under observation but is not a cause for concern, the Vatican said.

Pope Francis received the Eucharist on Monday morning and resumed some work in the afternoon. Later in the day, he called the parish priest in Gaza to express his solidarity.

Prayers for the Pope’s recovery have continued worldwide since he was admitted to the hospital on Feb. 14 with bronchitis. Concerns over his health escalated over the weekend when the Vatican reported that he had suffered “an asthma-like respiratory crisis of prolonged intensity” while suffering from pneumonia in both of his lungs. The episode required high-flow oxygen therapy, and the pope received a blood transfusion for platelet deficiency.

The hospital chaplain led prayers and Eucharistic adoration at the St. John Paul II Chapel on Monday, followed by a Mass.

On Monday evening, Catholics planned to gather in St. Peter’s Square to pray the Rosary for the Pope, led by Vatican Secretary of State Cardinal Pietro Parolin. It marks the first of a series of nightly Rosary prayers for the Pope at 9 p.m. this week led by members of the College of Cardinals living in Rome.

The Vatican said in its statement, “Pope Francis thanks all the faithful who have gathered to pray for his health in recent days.”