Prevalence of Low Titers of Pneumococcal Antibodies

Objective: 1) Determine the prevalence of low titers of pneumococcal antibodies (PAB) in patients with recurrent infections. 2) Assess whether there is a difference in PAB titers between patients unimmunized and patients vaccinated against pneumococcus.Method: Cross-sectional study between September 2006 and May 2008 in patients with recurrent infections. PAB levels against 10 serotypes were measured in all patients, and it was established if they had been vaccinated against pneumococcus. We compared the frequency of PAB low titers between both groups using the chi-square test.Results: A total of 257 patients were included in the study, aged between 0 and 68 years (median: 5 years) and with 54% being male. Sixty-one patients (24%) were vaccinated against pneumococcus. The prevalence of low titers of PAB (more than 50% of the serotypes with levels lower than 1.3 ug/mL) was 43% overall, with 8.2% and 53.6% in vaccinated and unvaccinated patients, respectively (P < .0001).Conclusion: Low levels of specific a...