Mode of splenectomy and immunogenicity of meningococcal vaccination in patients with hereditary spherocytosis

Background: Splenectomy predisposes patients to invasive disease from pneumococci, meningococci, and Haemophilus influenzae; immunization is mandatory. However, data on the impact of the splenectomy on vaccine immunogenicity are scarce. Methods: A total of 41 children with hereditary spherocytosis (aged 5·8–14·4 years) had complete (16) or near‐total (25) splenectomy. All received one dose of monovalent meningococcal C conjugate vaccine (MCV‐C) and, 2 months later, a tetravalent meningococcal polysaccharide vaccine (MPV‐ACWY). Serum bactericidal activity and antibodies against serogroups A and C were determined before and after they received MCV‐C, and 4 weeks after they received MPV‐ACWY. Results: Before vaccination, only four of the 16 children who had a complete splenectomy were protected against serogroup A, compared with 15 of the 25 who had near‐total splenectomy (P < 0·050), with the latter responding to immunization with significantly higher serogroup A serum bactericidal activity: geometric mean (95 per cent confidence interval) 1625.5 (49.9 to 3201.1) versus 980.6 (2.00 to 6204.1) (P < 0·050). All patients achieved putative protective serum bactericidal activity titres (at least 8) against serogroup C. Conclusion: Near‐total splenectomy provides a favourable immunological basis for natural and vaccine‐induced protection against meningococcal serogroup A and C infections. Sequential meningococcal vaccination is immunogenic in patients splenectomized for hereditary spherocytosis. Copyright © 2007 British Journal of Surgery Society Ltd. Published by John Wiley & Sons, Ltd. Better to conserve a piece of spleen