Table 1

‚ÄÉRisk factors for severe bronchiolitis

Host factorsEnvironmental factors
BPD, bronchopulmonary dysplasia; CF, cystic fibrosis
PretermPoverty
Age less than 6 weeksOver crowding
Congenital heart disease Chronic respiratory disease (BPD, CF)Exposure to postnatal tobacco smoke Malnutrition
Immune deficiency