So far, 2025 has been the winter of respiratory ailments, with influenza, COVID-19, and respiratory syncytial virus (RSV) making up three-fourths of what some are referring to as the "quademic." But one we haven't heard relatively much about is pneumonia.

The condition, which entails pneumonia in both lungs, is potentially grave, according to health experts. Pope Francis, who remains hospitalized, has bilateral pneumonia, the Vatican said on Tuesday.

“Double pneumonia” is not an official medical term. It may be being used to describe two different aspects of Pope Francis’s condition. Pope Francis has pneumonia in both lungs. This is known as “bilateral pneumonia”.