Characteristics of mpox cases diagnosed in Military Health System beneficiaries, May 2022-April 2024.

In May 2022, cases of mpox emerged beyond its historically endemic parts of Central and West Africa, primarily affecting men who have sex with men (MSM), and spreading via sexual networks. During this global outbreak the novel clinical and epidemiological characteristics of mpox disease were thoroughly documented in civilian populations but comparable data have not been reported for Military Health System (MHS) populations including beneficiaries. MHS cases were identified through a variety of data sources, including the Disease Reporting System internet (DRSi) and a customized query of ICD-10-CM (International Classification of Diseases, 10th Revision, Clinical Modification) encounter codes. Contemporaneous chart reviews of patients' electronic health records in the Armed Forces Health Longitudinal Technology Application (AHLTA) and MHS GENESIS were performed to characterize cases. A total of 146 confirmed and probable MHS cases were identified from May 2022 through April 2024. Most cases occurred among MSM, with the majority developing classic prodromal symptoms and some experiencing anogenital and urinary symptoms.