Immunogenicity for 16 serotypes of a unique schedule of pneumococcal vaccines in a high-risk population

Background: A unique schedule of 7-valent pneumococcal conjugate vaccine (7PCV) at 2,4 and 6 months of age and 23-valent pneumococcal polysaccharide vaccine (23PPV) at 18 months commenced for Australian Aboriginal infants in 2001. Methods: Anti-capsular IgG concentrations in vaccinated and non-vaccinated (historic control) infants were determined (blinded) by (22F absorbed) ELISA. Results: One month after dose 3 of 7PCV, geometric mean concentrations (GMCs) were > 1.95 mu g/ml and at least 89% of infants had IgG > 035 mu g/ml to all 7PCV serotypes. One month post-23PPV, IgG to 7PCV serotypes was > 035 mu g/ml for more than 96% infants (> 1.3 mu g/ml for at least 70%), and IgG to non-7PCV serotypes was > 035 mu g/ml for more than 50% infants (including serotype 6A, but not 12F (17%) or 19A (44%). Conclusion: 7PCV and 23PPV are immunogenic in this population. (C) 2008 Elsevier Ltd. All rights reserved.