Pope Francis has not been seen in public since entering the hospital, his longest absence from view since his papacy started in March 2013.

Pope Francis suffered two episodes of acute respiratory failure Monday, the Vatican said, a fresh setback in the worst health crisis of his papacy.

Pope Francis has spent 18 full days at Rome's Gemelli hospital recovering from double pneumonia. It's by far the longest hospitalization of his 12-year papacy, and there is no indication how long it may still last.