Immunogenicity and safety of a quadrivalent meningococcal tetanus toxoid-conjugate vaccine (MenACYW-TT) vs. a licensed quadrivalent meningococcal tetanus toxoid-conjugate vaccine in meningococcal vaccine-naïve and meningococcal C conjugate vaccine-primed toddlers: a phase III randomised study

Vaccination remains the best strategy to reduce invasive meningococcal disease. This study evaluated an investigational tetanus toxoid-conjugate quadrivalent meningococcal vaccine (MenACYW-TT) vs. a licensed tetanus toxoid-conjugate quadrivalent meningococcal vaccine (MCV4-TT) (NCT02955797). Healthy toddlers aged 12–23 months were included if they were either meningococcal vaccine-naïve or MenC conjugate (MCC) vaccine-primed (≥1 dose of MCC prior to 12 months of age). Vaccine-naïve participants were randomised 1:1 to either MenACYW-TT (n = 306) or MCV4-TT (n = 306). MCC-primed participants were randomised 2:1 to MenACYW-TT (n = 203) or MCV4-TT (n = 103). Antibody titres against each of the four meningococcal serogroups were measured by serum bactericidal antibody assay using the human complement. The co-primary objectives of this study were to demonstrate the non-inferiority of MenACYW-TT to MCV4-TT in terms of seroprotection (titres ≥1:8) at Day 30 in both vaccine-naïve and all participants (vaccine-naïve and MCC-primed groups pooled). The immune response for all four serogroups to MenACYW-TT was non-inferior to MCV4-TT in vaccine-naïve participants (seroprotection: range 83.6–99.3% and 81.4–91.6%, respectively) and all participants (seroprotection: range 83.6–99.3% and 81.4–98.0%, respectively). The safety profiles of both vaccines were comparable. MenACYW-TT was well-tolerated and demonstrated non-inferior immunogenicity when administered to MCC vaccine-primed and vaccine-naïve toddlers.

Quadrivalent Meningococcal Vaccine Uptake Among Men Who Have Sex With Men During a Meningococcal Outbreak in Los Angeles County, California, 2016-2017

Objective: The objective of our study was to assess meningococcal ACWY (MenACWY) vaccine uptake among men who have sex with men (MSM) during an ongoing, invasive meningococcal disease outbreak in Southern California. This research was important to inform future vaccination uptake interventions for this high-priority population. Methods: We conducted venue-based sampling to recruit and enroll MSM living in Los Angeles County, California, from December 2016 through February 2017. We conducted bivariate and multivariable analyses to evaluate associations between MenACWY vaccine uptake and other predetermined factors. Results: Of 368 participants, 138 (37.5%) reported receiving the MenACWY vaccine. In multivariable analyses, older age (adjusted odds ratio [aOR] = 2.57; 95% confidence interval [CI], 1.31-5.03), previous diagnosis of a sexually transmitted infection (aOR = 2.22; 95% CI, 1.14-4.30), belief that MenACWY vaccine is important (aOR = 3.49; 95% CI, 1.79-6.82), confidence in the MenACWY vaccine (aOR = 5.53; 95% CI, 3.11-9.83), and knowing someone who had been vaccinated (aOR = 5.82; 95% CI, 3.05-11.12) were significantly associated with MenACWY vaccine uptake. Conclusions: Our findings reflect low uptake of the recommended MenACWY vaccine among MSM after a local outbreak, despite public health efforts. In addition to ongoing, widespread campaigns to inform MSM about local outbreaks and vaccination recommendations, MSM may be responsive to direct outreach from peers who have been vaccinated.