J Infect Dis

BackgroundMeningococcal disease incidence in the U.S. is at an all-time low. In a previous study of Georgia high school students, meningococcal carriage prevalence was 7%. The purpose of this study was to measure the impact of a meningococcal conjugate vaccine on serogroup Y meningococcal carriage and to define the dynamics of carriage in high school students.MethodsThis was a prospective cohort study at 8 high schools, 4 each in Maryland and Georgia during a school year. In each state, 2 high schools were randomized for participating students to receive MCV4-DT at the beginning of the study and 2 at the end. Oropharyngeal swab cultures for meningococcal carriage were performed three times during the school year.ResultsAmong 3,311 students, prevalence of meningococcal carriage was 3.21%\u20134.01%. Phenotypically non-groupable strains accounted for 88% of carriage isolates. There were only 5 observed acquisitions of serogroup Y strains during the study; therefore, the impact of MCV4-DT on meningococcal carriage could not be determined.ConclusionsMeningococcal carriage rates in U.S. high school students were lower than expected and the vast majority of strains did not express capsule. These findings may help explain the historically low incidence of meningococcal disease in the U.S.20142018-01-24T00:00:00ZCC999999/Intramural CDC HHS/United States25505298PMC5783552749