One of the greatest risk factors for getting bronchiolitis is being younger than 6 months old, because the lungs and immune system aren't yet fully developed.

Other factors that have been associated with an increased risk of bronchiolitis in infants, or more severe illness due to bronchiolitis, include:

  • Never having been breast-fed — breast-fed babies receive immune benefits from the mother
  • Premature birth
  • An underlying heart or lung condition
  • A depressed immune system
  • Exposure to tobacco smoke
  • Contact with multiple children, such as in a child care setting
  • Living in a crowded environment
  • Having siblings who attend school or child care and bring home the infection
May. 07, 2013