Natural and vaccine-induced immunity to meningococcus C (MenC) was
evaluated in asplenic adolescents and adults with beta-thalassemia. At
baseline 19.3% of patients and 22.8% age-matched controls had positive
(> 2 mu g/ml) naturally acquired Men C- specific IgG antibodies;
patients had a lower probability of having protective SBA compared to
controls (OR =21, p = 0.012). MenC conjugate vaccine (MCC) induced
protective IgG concentrations in 63% of patients and 90.1% of
controls. SBA increased significantly post vaccination and there were no
differences between patients and controls; however patients had
significantly lower IgG concentrations post vaccination compared to
controls (4.52 vs 10.94 mu g/ml. p < 0.001, respectively). A second dose
of MCC given to 11 patients who had received MCC in the past induced
higher IgG compared to primary response (p =, 0.001). Naturally- and
vaccine-induced immunity to MenC is impaired in asplenic
beta-thalassemics; a second dose of MCC improves vaccine immunogenicity
and is essential for their optimal protection. (C) 2011 Elsevier Ltd.
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