Vatican authorities said Monday that Pope Francis has a complex infection in his respiratory system and will require more targeted drug treatment. Here's what to know.

Pope Francis has not been keeping well. Two days after Vatican authorities said he had been diagnosed with a polymicrobial respiratory tract infection, latest reports say he has developed double pneumonia and his condition remains "complex".

Pope Francis has been in the hospital since Friday with a respiratory tract infection. Officials with the Vatican said Monday that the 88-year-old’s infection requires further hospitalization and a change in drug therapy. Francis has had several health ailments over the years.