Background: Neisseria meningitidis serogroup B (MenB) causes most meningitis outbreaks worldwide. We evaluated the ability of the 4-component MenB vaccine (4CMenB) to induce bactericidal activity against outbreak strains in adolescents.
Methods: Individual sera from 20 United States and 23 Chilean adolescents who received 2 doses of 4CMenB 2 months apart were assayed at prevaccination and 1 month after second dose using a human complement serum bactericidal antibody assay (hSBA) against a full or subset strain panel consisting of 14 MenB outbreak strains and 1 MenW hyperendemic strain collected between 2001 and 2017 in the United States, United Kingdom, and France. Bactericidal activity was determined as the percentage of adolescents with hSBA titer ≥1:4 or ≥1:8.
Results: One month after the second 4CMenB dose, antibodies from 65% to 100% of the US adolescents were able to kill 12 of 15 strains at 1:4 dilution. The remaining 3 strains were killed by 45%, 25%, and 15% of US adolescent sera. Similar percentages exhibited hSBA titers of ≥1:8. Across a subset of 4 strains, point estimates for the percentages of Chilean and US adolescents with hSBA titers of ≥1:4 after the second 4CMenB dose were similar (100% for strain M27703, 74% vs. 80% for M26312, 52% vs. 45% for M08 0240745), except for strain M39090 (91% vs. 65%).
Conclusions: This study was the first to evaluate bactericidal activity elicited by a MenB vaccine against 15 outbreak strains. Two doses of 4CMenB elicited bactericidal activity against MenB outbreak strains and a hyperendemic MenW strain.
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