Objective: Although invasive pneumococcal disease is infrequent in cystic fibrosis (CF), it is recommended that all patients with CF receive pneumococcal immunization. As part of a comprehensive program to immunize our clinic population, we obtained preimmunization anti-pneumococcal antibody levels. We hypothesized that the percentage of CF patients without protective levels of anti-pneumococcal antibody levels would be high, as they are exposed to frequent antibiotic therapy that may eradicate organisms before generation of an antibody response.
Methods: An observational study of 100 patients with CF, aged 1 to 39 years, was conducted in a regional CF center. Preimmunization anti-pneumococcal antibody levels against 6 serotypes were measured by enzyme-linked immunosorbent assay. Protective antibody levels were defined as >200 ng/mL.
Results: A majority of CF patients-61% to 100%, depending on age and serotype-had protective levels of pneumococcal antibody. There was a significant positive correlation between antibody level and age for 5 of the 6 serotypes tested.
Conclusions: In contradistinction to our hypothesis, the majority of CF patients have protective preimmunization anti-pneumococcal antibody levels. However, a significant proportion-between 17% and 39%, depending on the serotype-did not exhibit adequate levels. Therefore, we concur with current recommendations for pneumococcal immunization in CF.