Objectives. We sought to describe Neisseria meningitidis immunity and its association with pharyngeal carriage in Burkina Faso, where N. meningitidis serogroup W-135 and serogroup A disease are hyperendemic and most of the population received polysaccharide A/C vaccine during 2002. Methods. We collected oropharyngeal swab samples from healthy residents of Bobo-Dioulasso (4-14 years old, n = 238; 15-29 years old, n = 250) monthly during February-June 2003; N. meningitidis isolates were analyzed using polymerase chain reaction and serogrouped using immune sera. Serum samples were collected at the first and last clinic visit and analyzed for anti-A, anti-C, anti-W-135, and anti-Y immunoglobulin G (IgG) concentrations and anti-A and anti-W-135 bactericidal titers. Results. N. meningitidis was carried at least once by 18% of participants; this carriage included strains from serogroups W-135 (5%) and Y and X (both <1%) but not from serogroups A, B, or C. At baseline, the prevalence of putatively protective specific IgG concentrations (≥2 μg/mL) and bactericidal titers (≥8) was 85% and 54%, respectively, against serogroup A, and 6% and 22%, respectively, against serogroup W-135. Putatively protective anti-W-135 IgG concentrations and bactericidal titers were of short duration and were not associated with carriage. Conclusion. N. meningitidis serogroup W-135 strains did not induce immunity, despite their circulation. Carriage of serogroup A strains was rare despite the hyperendemic incidence of serogroup A meningitis during 2003 in Bobo-Dioulasso. A vaccine that includes serogroup W-135 antigen and eliminates serogroup A carriage is needed for sub-Saharan Africa.
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Potential conflicts of interest: J.E.M., B.-M.N.-L., and B.D.G. work for the Agence de Médecine Préventive, which receives substantial financial support from Sanofi Pasteur, a manufacturer of meningococcal vaccines. R.B. has received financial support for attending meetings from, served as a consultant for, and performed contract research for Alexion Pharmaceuticals, Baxter Bioscience, Chiron Vaccines, Fujisawa, GlaxoSmithKline, Microscience, Sanofi Pasteur, Wyeth Vaccines, and Xenova Research. All other authors report no conflicts of interest.