Clinical manifestations during admission were further classified as: 1) uncomplicated (admitted for observation, slight dehydration), 2) respiratory problems such as wheezing, tracheitis, croup and obstructive apnea, 3) suspected bacterial infections such as pneumonia, empyema, bacterial tonsillitis and otitis media, 4) seizures (both febrile and afebrile), 5) other manifestations (gastroenteritis