Prevalence of pertussis IgG antibodies in children in Palermo, Italy.
The prevalence of IgG antibodies to Bordetella pertussis in a sample of 615 1-12-year-old unvaccinated children in Palermo was estimated by ELISA. The overall prevalence was 56%; it increased from 24% in one to three-year-old children to 67% in 11-12-year-old children (p less than 0.01). IgG antibody prevalence was not associated with the father's years of schooling (OR 1), nor with the family size (OR 1.3; C.I. 95% = 0.8-2.2). For children aged one the three years, serological results showed that the history of pertussis reported by parents in questionnaires gave high specificity (93.2%) and negative predictive value (85.4%). Our seroepidemiological study evidences a great exposure of children to B. pertussis in Palermo, with a high proportion of infections occurring after three years of age.