<unk>  typically affects infants and children younger than two years, principally during the autumn and winter. It is the leading cause of hospital admission for respiratory disease among infants in the United States and accounts for one out of every 13 primary care visits.<unk>  accounts for 3% of emergency department visits for children under 2 years old.<unk>  is the most frequent lower respiratory tract infection and hospitalization in infants worldwide.
Bronchiolitis
Heart failure
Bronchitis
Asthma
Bronchitis kettle
Pneumonia
Croup
Cystic fibrosis