Monkeypox Virus Detected in Anorectal Samples From Asymptomatic Patients

TUESDAY, Aug. 16, 2022 — Asymptomatic cases of men who have sex with men (MSM) who are positive for monkeypox virus (MPXV) are described in a research letter published online Aug. 16 in the Annals of Internal Medicine.

Valentine Marie Ferré, Pharm.D., from the Université Paris Cité, and colleagues examined the presence of MPXV in anorectal samples among asymptomatic MSM routinely screened for bacterial sexually transmitted infections.

A total of 706 MSM visited the clinic during the study period; 383 had symptoms suggestive of MPXV infection and 271 of those with symptoms had confirmed MPXV infection. The researchers found that 323 of the MSM had no MPVX symptoms; of these, 213 had anal swabs collected and were negative for Neisseria gonorrhoeae and Chlamydia trachomatis. MPXV polymerase chain reaction (PCR) was performed on 200 of 213 anal swabs and was positive in 6.5 percent. Eight of the 13 MSM testing positive were living with HIV; all had undetectable HIV-1 viral load. None of the 13 MPXV-positive, initially asymptomatic participants reported symptoms suggestive of MPXV infection, but two subsequently presented with symptoms. Three of the 187 asymptomatic participants who tested negative for MPXV presented to the clinic more than three weeks after the initial negative test with symptoms suggestive of infection and tested positive.

“Whether this indicates viral shedding that can lead to transmission is unknown,” the authors write. “If so, the practice of ring postexposure vaccination around symptomatic persons with probable or confirmed MPXV infection may not be sufficient to contain spread.”

Abstract/Full Text

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Posted August 2022