The Vatican says Pope Francis’ respiratory tract infection is presenting a “complex clinical picture” that will require further hospitalization.

The pope, 88, was diagnosed with a polymicrobial infection after he was hospitalized in Rome on Friday for bronchitis.

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.