Longitudinal Analysis of Mpox Virus DNA Detectability From Multiple Specimen Types During Acute Illness: A Cohort Study

Abstract

Abstract Background Longitudinal data on the detectability of monkeypox virus (MPXV) genetic material in different specimen types are scarce. Methods We describe MPXV-specific polymerase chain reaction (PCR) results from adults with confirmed mpox infection from Toronto, Canada, including a cohort undergoing weekly collection of specimens from multiple anatomic sites until 1 week after skin lesions had fully healed. We quantified the time from symptom onset to resolution of detectable viral DNA (computed tomography [Ct] ≥ 35) by modeling exponential decay in Ct value as a function of illness day for each site, censoring at the time of tecovirimat initiation. Results Among 64 men who have sex with men, the median (interquartile range [IQR]) age was 39 (32.75–45.25) years, and 49% had HIV. Twenty received tecovirimat. Viral DNA was detectable (Ct < 35) at baseline in 74% of genital/buttock/perianal skin swabs, 56% of other skin swabs, 44% of rectal swabs, 37% of throat swabs, 27% of urine, 26% of nasopharyngeal swabs, and 8% of semen samples. The median time to resolution of detectable DNA (IQR) was longest for genital/buttock/perianal skin and other skin swabs at 30.0 (23.0–47.9) and 22.4 (16.6–29.4) days, respectively, and shortest for nasopharyngeal swabs and semen at 0 (0–12.1) and 0 (0–0) days, respectively. We did not observe an effect of tecovirimat on the rate of decay in viral DNA detectability in any specimen type (all P > .05). Conclusions MPXV DNA detectability varies by specimen type and persists for over 3–4 weeks in skin specimens. The rate of decay did not differ by tecovirimat use in this nonrandomized study.