What does Pope Francis having "double pneumonia" mean? What should you look for in the elderly? How can you avoid getting pneumonia?

The Vatican announced that Pope Francis is battling double pneumonia, which has led to breathing difficulties. His infection is considered complex.

Pope Francis was found to have pneumonia in both his lungs Tuesday and his condition remains "complex," the Vatican said in a health update on the 88-year-old pontiff who was hospitalized last week. The big picture: The pope was admitted to Rome's Agostino Gemelli Hospital on Friday with bronchitis symptoms and his treatment was changed after doctors found he had a polymicrobial infection of the respiratory tract.