Mpox DNA clearance in semen over 6-month follow-up.

Sexual intercourse is a well-established way of transmission of mpox infection. However, it is still uncertain whether semen may represent a viral reservoir. The aim of the study was to evaluate the clearance of viral DNA in semen samples from individuals diagnosed with mpox infection over 6-month follow-up. This prospective, observational, single-center study was conducted at IRCCS San Raffaele Scientific Institute, Milan, Italy, between May and October 2022 in 140 individuals who attended Sexual Health Clinic and diagnosed with mpox infection. Semen samples were collected and analyzed by real-time polymerase chain reaction assays. The baseline collection was performed in 64 (46%) of 140 men diagnosed with mpox infection. The viral DNA was detected in 43 (67%) with median cycle threshold (Ct) 34 (interquartile range [IQR] 31-36). The research was repeated in 32 (74%) and viral DNA clearance was observed in all within 6 months in a median time of 10.5 days (IQR 7-33). Viral clearance occurred in all tested individuals, mostly within 2 weeks since the first positive test. These findings suggest a transient presence of viral DNA in semen and do not support the hypothesis of reservoir. More studies on mpox DNA detection in semen with viral culture and extended follow-up are needed.