Clinical and microbiologic features of children presenting with pertussis to a Canadian pediatric hospital during an elevenyear period

To characterize the morbidity of pertussis in Canada, we did a retrospective review of all children with laboratory-confirmed pertussis seen at the Hospital for Sick Children, Toronto, between 1980 and 1990. A total of 975 patients were identified, of which 223 (23) were admitted to hospital. The peak incidence of disease was observed in the fall. The incidence of disease did not vary with gender. Only 41 of children admitted had the classical symptoms of pertussis (paroxysmal cough and whoop). Compared with children older than 6 months of age, children younger than 6 months of age were more likely to be hospitalized, tended to be hospitalized longer, were less likely to be age-appropriately vaccinated and were more likely to require intensive care unit monitoring. Seventeen (8) of 223 children required intensive care unit monitoring, and 12 of these children required mechanical ventilation therapy, for a duration of 3.5 ± 0.6 days (mean ± SD). One (0.1) patient with secondary bacterial pneumonia died. This hospital-based study indicates that pertussis continues to be a cause of serious illness in children, particularly those younger than 6 months of age.