[Whooping cough necessitating hospitalization in Denmark, 1980-1986]

Information from the Danish National Patient Register revealed that 817 patients had been hospitalized with verified whooping cough during the period 1980-1986. The letters of discharge or the case records were obtained for all patients under one year for the entire period and for all patients over one year for the period 1984-1986, a total of 627 persons. These were supplemented by information from forms with information about positive cultures for whooping cough in nasopharyngeal swabs and from individual notifications about children under one year. 65% of the hospitalized patients were under one year and only 2% over 15 years. The severity of the disease measured by the duration of hospitalization and the presence of serious complications and symptoms decreased with age. The average duration of hospitalization was 15 days for children under one year and seven days for children over one year. Five children died. One child developed epilepsy, nine of the remainder required assisted respiration and recovered apparently without permanent damage. Out of the 627 patients who were hospitalized, pneumonia developed in 12%, seizures in 2% under one year and 5% over one year, apnoea occurred in 10% under one year and 2% over one year and cyanosis occurred in 61% under one year and 30% over one year. None of the vaccinated children developed seizures, required assisted ventilation or died and only 2% had apnoea as compared with 7% in the unvaccinated children. Children under two months and children in whom vaccination was contraindicated were responsible for 56% of the hospitalizations among children under one year and for 79% of the most severe cases.(ABSTRACT TRUNCATED AT 250 WORDS)