How common is whooping cough in a nonvaccinating country?

In Sweden general vaccination with a whole cell pertussis vaccine was recommended from 1953. In 1979 the recommendation was withdrawn because the Swedish-made vaccine had become ineffective. In order to determine the incidence of the disease in a nonvaccinating country, 400 children born in 1980 were randomly selected from the population register of Göteborg, Sweden. The parents of the children were interviewed in 1990, when the children were 10 years old. The parents of 377 children could be reached, and of those 372 were not vaccinated against pertussis. Of the nonvaccinated children 61% had experienced clinically typical whooping cough; 195 (119 with and 76 without a history of whooping cough) agreed to donate a serum sample for determination of antibodies against pertussis toxin, filamentous hemagglutinin and pertactin. Of the children with a history of whooping cough, 91% had antibodies against pertussis toxin, as had 64% of the children without a history of disease. All but 3 children had antibodies against filamentous hemagglutinin and all 195 children had antibodies against pertactin. The antibody titers against the 2 last mentioned proteins did not differ between children with and without a history of whooping cough or between children with and without antibodies against pertussis toxin.