Please note this is an updated version of the factsheet originally published on 9 September.

This factsheet provides information about Respiratory Syncytial Virus (RSV), who is at risk, how to recognise and manage it, and when to seek medical help. It also covers bronchiolitis, an infection which causes the smallest airways in the lungs (the bronchioles) to become infected and inflamed. RSV is the most common cause of bronchiolitis in children aged under 2 years.