Clinical course of whooping cough in children younger than six months.

The patient records of 59 children aged 2--26 weeks with culture-verified pertussis were analysed. Twenty-four of them were hospitalized, in most cases for social reasons. Only one child with hypothyroidism and a complicating pneumonia was critically ill. Seventeen of the 35 non-hospitalized patients had a mild disease without developing typical whooping attacks. Thirteen children were treated with erythromycin in the catarrhal stage. There was a tendency towards milder disease in this group but the differences compared to untreated children were not statistically significant.