In a study involving 16 men who have sex with men (MSM) infected with mpox, viral DNA remained detectable in skin lesions for 17 to 31 days after symptom onset. The findings were published in the Journal of the American Academy of Dermatology.
All MSM included in the study had contracted mpox through sexual transmission, and their median age was 36. None were treated with antivirals throughout the course of the study. Swabs were obtained on day 1 of study enrollment and during more than a month of follow-up.
Based on these data, we can question whether three weeks of isolation is sufficient.
On day 1 of the study, all subjects had detectable viral DNA in skin lesions, and 94% had detectable viral DNA in the oropharynx. On day 7, all subjects tested positive in the skin lesions, and 88% tested positive in the oropharynx, the authors said.
"On Day 14, although all subjects had healing skin lesions, most (88%) tested positive in the lesions; in contrast, only 50% tested positive in the oropharynx," the authors said.
The average day of DNA detection in skin lesions following symptom onset was 23 days (95% confidence interval, 21 to 25 days), and 21 days in the oropharynx.
Guidelines might not be sufficient
Currently, the Centers for Disease Control and Prevention (CDC) recommends mpox patients wait 21 days before resuming sexual activity to avoid the spread of the disease.
"Based on these data, we can question whether three weeks of isolation is sufficient," the authors write. "However, the presence of genetic material in samples does not mean the presence of viable viral particles; thus, virus infectivity tests should be conducted to understand the significance of the persistence of viral DNA in skin lesions and the oropharynx."