The Vatican said Francis' respiratory infection also involves asthmatic bronchitis, which requires the use of cortisone antibiotic treatment. “Laboratory tests, chest X-ray, and the Holy Father’s ...

Bronchitis can lead to pneumonia, which is a deeper and far more serious infection of the lungs' air sacs. Pneumonia can develop in part of one lung or an entire lung or both lungs.

Infections tend to be most common among older children and adolescents but in 2024 have been rampant among young children, the CDC says.