What is the most common viral cause of bronchiolitis in infants?

Respiratory syncytial virus (RSV) is recognized as the most common viral cause of bronchiolitis in infants. This virus is particularly prevalent in the winter months, leading to widespread outbreaks. RSV infects the respiratory epithelium, resulting in airway inflammation, increased mucus production, and narrowed airways, which are hallmarks of bronchiolitis. The age group primarily affected by RSV includes infants under two years old, which is why it is a critical focus in pediatric care.

Influenza virus, while it can cause similar respiratory symptoms, is not the leading cause of bronchiolitis specifically. Parainfluenza virus and various strains of coronaviruses can also contribute to respiratory illnesses in children, but they do not occur with the same frequency or severity in the context of bronchiolitis as RSV does. Thus, RSV's predominance as a causative agent underscores its importance in pediatric respiratory health.