Characterization of <i>Neisseria meningitidis</i> Carriage in Military at Joint Base San Antonio, Texas, June-August 2024

INTRODUCTION: The bacteria, Neisseria meningitidis, is a frequent colonizer of the oropharynx, but can also lead to invasive disease with encapsulated strains. All military services currently use a quadrivalent polysaccharide vaccine against serogroups A, C, W, and Y to prevent outbreaks among trainees. With the introduction of novel vaccines against serogroup B, this study evaluated the current carriage of N. meningitidis among military trainees. MATERIALS AND METHODS: Between June and August 2024, a sample of 909 military trainees received oropharyngeal sampling at the time of beginning basic military training before universal vaccination and penicillin administration. All isolates were serogrouped by polymerase chain reaction (PCR) and whole genome sequencing. This study was reviewed by the Lackland Institutional Review Board and determined to be occupational surveillance and not human research. RESULTS: Thirty-five (3.9%) trainees had carriage of N. meningitidis. While the PCR suggested, 11 (31%) isolates were encapsulated with Serogroup B, to be the most common colonizing isolate (n = 8, 22%). However, when characterized by whole genome sequencing, only one isolate, expressing serogroup C, was predicted to have a functional capsule. CONCLUSIONS: These data demonstrate the continued threat of N. meningitidis in military training populations and the need for whole genome sequencing in characterizing colonizing isolates and the determination of vaccination policies. Furthermore, these data support the current policy of quadrivalent vaccination in the military training population.