Long-Term Mpox Sequelae 11 to 18 Months After Acute Illness : A Cohort Study in Two U.S. Cities

Little was known about persistent sequelae of mpox before the 2022 multinational clade II mpox virus outbreak.

To characterize post-mpox sequelae 11 to 18 months after acute mpox diagnosis and compare outbreak-associated psychosocial and behavioral impact between at-risk persons who had or did not have mpox.

Cohort study.

New York City, New York, and Houston, Texas.

Adults attending HIV, pre-exposure prophylaxis, or sexually transmitted infection clinics diagnosed with mpox during May 2022 to January 2023 (post-mpox) or at risk for but never diagnosed with mpox (no-mpox).

All participants completed psychosocial and behavioral self-assessments. A clinician also assessed post-mpox participants by clinical history and physical examination; persisting mpox physical sequelae were classified by tissue affected and effect on appearance or function. Associations between post-mpox physical sequelae and medical history, acute mpox severity, and sociodemographic characteristics were assessed using marginally adjusted probabilities (presented as risk ratios with 95% CIs).

A total of 154 post-mpox and 201 no-mpox participants were enrolled. The proportion of participants reporting increased psychobehavioral symptoms was generally similar between groups. Fifty-eight percent (89 of 154) of post-mpox participants had at least 1 persistent sequela; 56% (86 of 154) were appearance related, of which 51% (44 of 86) occurred at 2 or fewer sites. Thirteen percent (20 of 154) of post-mpox participants had functional sequelae, of whom 50% (10 of 20) and 35% (7 of 20) had ongoing anorectal and urinary dysfunction, respectively.

Participants may not be representative of mpox-affected and susceptible populations. Findings may over- or underestimate frequency or severity of severe mpox sequelae.

Post-mpox sequelae frequently persisted 11 to 18 months after acute mpox, with limited body distribution or physical morbidity but with continued social and sexual effects.

Centers for Disease Control and Prevention.