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

ABSTRACT

BACKGROUND: Pneumococcal 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. METHODS: We 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. RESULTS: Nine children had been immunized with Prevenar 7, and all had serotype-specific pneumococcal antibody levels in the protective range (>0.35mg/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. CONCLUSIONS: Impaired antibody responses to immunization with Pneumovax II are common in children with CF and this may be associated with increased disease severity.