As Pope Francis has battled double pneumonia in hospital for nearly three weeks, talk of the 88-year-old pontiff's death or resignation has become almost commonplace. Some newspapers have published articles informing their readers about what to expect during the papal funeral.

Pope Francis is still in a Rome hospital Monday as the 88-year-old pontiff continues to battle double pneumonia for an 18th day. CBS News senior foreign correspondent Seth Doane has more.

Pope Francis is being treated in hospital for double pneumonia — but what is this condition, and why might the pope be particularly vulnerable to it?