2-dose, 3-dose vax schedules active against several meningococcal serogroup B strains

Both the 2-dose and 3-dose vaccination schedules of the four-component meningococcal serogroup B vaccine (4CMenB) appear to provide protection against a panel epidemiologically relevant strains in adolescents and young adults, according to a phase III study presented at ESPID 2023.

Vaccine effectiveness was demonstrated at a population and individual level, with no clinically meaningful differences in immunogenicity, reported lead investigator Dr Terry Nolan of the Peter Doherty Institute for Infection & Immunity in Melbourne, Australia.

For the study, Nolan and colleagues randomly assigned 3,651 healthy individuals aged 10–25 years to receive 4CMenB (n=1,808) at a schedule of either three doses (0-2-6 months) or two doses (0-6 months or 0-2 months), the investigational pentavalent meningococcal vaccine (MenABCWY; n=1,666), or the novel quadrivalent glycoconjugate vaccine (MenACWY-CRM; control, n=177).

Vaccine effectiveness was evaluated via two approaches. First was test-based, where the percentages of serum samples without bactericidal activity against 110-strain panel* was compared after the second/third 4CMenB dose vs after the MenACWY dose. Second was responder-based, defined as the percentage of participants whose sera’s bactericidal activity showed ≥70 percent killed strains at 1 month after the second/third 4CMenB dose. Success was defined at a lower limit of two-sided 97.5 percent confidence interval [CI] of greater than 65 percent.

“Primary study objectives for 4CMenB were met,” Nolan said.

Test-based vaccine effectiveness for 4CMenB was 83.2 percent (97.5 percent CI, 81.9–84.4) in the 0-2-6-schedule group, 81.8 percent (97.5 percent CI, 80.4–83.1) in the 0-6-schedule group, and 78.7 percent (97.5 percent CI, 77.2–80.1) in the 0-2-schedule group. [ESPID 2023, abstract PD0123]

The respective responder-based vaccine effectiveness was 93.4 percent (97.5 percent CI, 91.2–95.2), 89.8 percent (97.5 percent CI, 87.2–92.0), 84.8 percent (97.5 percent CI, 81.8–87.5) in the 0-2-6-, 0-6-, and 0-2-schedule groups.

“Immune responses against MenB indicator strains were robust, [with] the percentages of participants with fourfold rise in human serum bactericidal antibody (hSBA) titre and with hSBA titre at or below the lower limit of quantitation [being] similar between the 4CMenB groups,” Nolan pointed out.

In terms of safety, the 4CMenB 2- and 3-dose schedules were tolerated well, with no safety concerns, he added. “[The drug’s] safety profile is in line with previous 4CMenB safety observations in adolescents and young adults.” [mSphere 2021;6:e0055321; Vaccine 2015;33:4437-4445; Lancet 2014;384:2123-2131; Lancet 2012;379:617-624]

*The 110 MenB strain panel contains a repertoire of antigen genotypes that represents approximately 89 percent of MenB strains circulating worldwide, ranging from 87 percent for European stains to 95 percent for US and 97 percent for Australian strain panes. [mSphere 2022;7:e0038522]