How long is bronchiolitis contagious?

Bronchiolitis can be contagious while its underlying respiratory virus is spreading, including before and during the child’s breathing symptoms. The exact period varies by virus and person, so the end of cough is not always a precise marker. Coughing may continue after the child is less infectious.

The same virus may cause a cold in one contact and bronchiolitis in a baby. Spread occurs through respiratory secretions and contaminated hands or objects. A lingering [Cough](/symptoms/cough/) does not necessarily mean ongoing high transmission, but good hygiene remains sensible while symptoms continue. [Bronchiolitis](/conditions/bronchiolitis/) can be more serious in very young babies.

Keep a symptomatic child away from babies and vulnerable people when possible, wash hands before contact, cover coughs, clean shared objects, and do not share feeding items. Follow nursery or school advice about returning. Arrange a [Child Health Consultation](/treatments/consultations-and-assessment/child-health-consultation/) if you are unsure about contact with others.

Urgent assessment is needed for breathing pauses, blue or grey lips, severe chest indrawing, unusual sleepiness, or inability to drink. Seek prompt medical advice if feeds are falling, urine output is reduced, or breathing is getting harder. A [Fever](/symptoms/fever/) or [Wheezing](/symptoms/wheezing/) should be judged alongside these signs.

Ask when your child may safely mix with siblings or classmates, whether a vulnerable household member needs extra precautions, and what symptoms warrant review. Ask whether [Nebuliser Treatment](/treatments/acute-and-urgent-care/nebuliser-treatment/) is relevant to the child’s breathing.