A serogroup B meningococcal vaccine (4CMenB) has been licensed by the European commission for use in various infant schedules. However, data are limited on persistence of serum bactericidal antibodies (SBA), which is necessary to inform cost-effectiveness analysis.
Sera were obtained from 3 groups of 5-year-old children previously immunized at 6, 8, 12 and 40 months with either 4CMenB or rMenB (which lacks the outer membrane vesicle of 4CMenB) or at 40 and 42 months with 4CMenB only. Forty-nine control children were also recruited and blood obtained before and after 2 doses of 4CMenB at 60 and 62 months of age. Sera were tested for SBA to meningococcal B reference strains.
At 5 years of age, 67% of those receiving 4CMenB in infancy had SBA titers ≥1:4 for strain 44/76, 100% for 5/99, 17% for NZ98/254 and 45% for M10713. Results for rMenB recipients varied from 0 (NZ98/254) to 100% (5/99). Of those immunized with 4CMenB at 40 and 42 months, 38% had SBA titers ≥1:4 at age 5 for 44/76, 100% for 5/99, 0% (NZ98/254) and 83% (M10713). Among controls, SBA titers were ≥1:4 in 4% (H44/76, 5/99), 0% (NZ98/254) and 67% (M10713) at baseline, increasing to 100% (H44/76 and 5/99), 89% (NZ98/254) and 97% (M10713) postimmunization.
The variable rates of waning of antibody to the 4 components of 4CMenB complicates estimates of duration of protection and should be taken into account in cost-effectiveness analyses. A 2-dose schedule of 4CMenB in 5-year-old children was immunogenic.