Immunologic memory 5 years after meningococcal A/C conjugate vaccination in infancy

Abstract

Infant vaccination with meningococcal conjugates may provide long-term protection against disease. Antibody levels and immunologic memory were assessed in 5-year-old Gambian children who received meningococcal A/C conjugate vaccination (MenA/C) in infancy. At 2 years, they were randomized to receive a booster of MenA/C (conjugate group), meningococcal A/C polysaccharide (MPS group), or inactivated polio vaccine (PV group). All groups were revaccinated with 10 μg MPS at 5 years of age, as were 39 previously unvaccinated age-matched control subjects. Before revaccination, titers were higher in the conjugate and MPS groups than in control subjects (P < .001). Thus, immunologic memory was sustained for ≥5 years; however, MPS challenge at 2 years interfered with a subsequent memory response. © Oxford University Press 2001.