Pneumococcal polysaccharide vaccine responses are impaired in a subgroup of children with cystic fibrosis

BackgroundPneumococcal immunization is recommended in children with cystic fibrosis (CF). To date, however, there are no published studies on the efficacy of pneumococcal vaccination in this group of patients.MethodsWe carried out a retrospective study of serotype-specific pneumococcal antibody responses to immunization with Prevenar 7 and Pneumovax II in a cohort of children with CF.ResultsNine children had been immunized with Prevenar 7, and all had serotype-specific pneumococcal antibody levels in the protective range (> 0.35 mg/L) to all 7 immunizing serotypes. In contrast, only 7 of 33 patients (21%) immunized with Pneumovax II made protective antibody responses to all 7 serotypes, and 3 failed to make protective antibodies to any of the serotypes. Controlling for age as a confounder in the analysis, children with impaired antibody responses to pneumococcal polysaccharide (Pneumovax II) immunization had lower Shwachman–Kulczycki scores than children with normal polysaccharide antibody responses. All isolates of Pseudomonas aeruginosa occurred in patients with impaired anti-pneumococcal antibody responses, and a broader range of respiratory pathogens was isolated from these children.ConclusionsImpaired antibody responses to immunization with Pneumovax II are common in children with CF and this may be associated with increased disease severity.