Mbaeyi S, Pondo T, Blain T, et al. - Researchers here examined if and how the quadrivalent meningococcal conjugate vaccination program in adolescents affected the incidence of meningococcal disease in the United States. In this cohort study, they analyzed surveillance data including all confirmed and probable cases of Neisseria meningitidis reported to the National Notifiable Diseases Surveillance System from January 1, 2000, to December 31, 2017. Declining trend was noted in the incidence of meningococcal disease prior to introduction of the vaccine. However, this cohort study revealed nearly 2-fold to 3-fold accelerated rates of decline in incidence of meningococcal disease due to serogroups C, W, and Y in vaccinated age groups, with greater rates of decline in states with high quadrivalent meningococcal conjugate vaccine coverage. Per these findings, the quadrivalent meningococcal conjugate vaccine alone cannot explain the decline of the incidence of meningococcal disease in the United States, however, the data suggest vaccination to be associated with reducing disease rates in adolescents.