Prevention of Meningococcal Serogroup B Infections in Children: A Protein‐Based Vaccine Induces Immunologic Memory

Abstract

Immunologic memory against meningococci was studied in 177 children (100 children were 10–11 years old and 77 were 5–6 years old) 2.5 years after vaccination with hexavalent meningococcal outer membrane vesicle (OMV) vaccine or hepatitis B (HepB) vaccine. Children were revaccinated with monovalent P1.7^h,4 meningococcal OMV vaccine. Serum bactericidal antibodies (SBAs) were measured before revaccination and after 4–6 weeks. A minimum 4-fold increase in SBAs against serosubtype P1.7^h,4 was detected in 48.5% of the children after hexavalent meningococcal vaccine and in 8.9% after HepB vaccine. Of the initial responders given hexavalent meningococcal vaccine, 78% had ⩾4-fold increase in SBAs against strain P1.4. Thus, immunologic memory is present in toddlers and school-aged children previously given 3 hexavalent meningococcal vaccinations. Booster vaccination with monovalent P1.7^h,4 meningococcal OMV vaccine induces a significant increase in SBAs against serosubtype P1.7^h,4 and cross-reactivity against other serosubtypes in the hexavalent vaccine