Monkeypox virus was detected on the anal swabs of asymptomatic men who’ve sex with men (MSM) at a sexual health clinic in Paris, in accordance with a retrospective study.
Among 213 MSM who had anal swabs collected for Chlamydia trachomatis and Neisseria gonorrhoeae, 200 underwent monkeypox-specific PCR testing and 6.5% were positive for the herpes virus, reported Charlotte Charpentier, PharmD, PhD, of Hpital Bichat-Claude Bernard in Paris, and colleagues.
“Whether this means that viral shedding that may result in transmission is unknown. If that’s the case, the practice of ring postexposure vaccination around symptomatic persons with probable or confirmed monkeypox virus infection might not be sufficient to contain spread,” they wrote in the Annals of Internal Medicine.
All 13 affected men were advised to limit sex for 21 days also to notify recent sexual partners. While none of the men initially reported symptoms, two subsequently offered symptoms at medical clinic — one with anal rash and another with pharyngitis and fever but no anal symptoms.
Of the rest of the 187 men who initially tested negative, three presented to the clinic with symptoms over 3 weeks later and tested positive.
These findings come in line with a recently available study that reported that two asymptomatic patients were found to be infected with the monkeypox virus.
“Though it isn’t yet clear if the positive PCR result represents the current presence of infectious virus, you won’t be surprising if it’s present as the chance for asymptomatic infections isn’t a fresh finding,” wrote Stuart N. Isaacs, MD, of the Perelman School of Medicine at the University of Pennsylvania in Philadelphia, within an accompanying editorial.
“However, it increases the question of whether asymptomatic or subclinical infections are adding to the existing worldwide outbreak,” he added.
France has issued an advisory for several MSM with multiple partners to be vaccinated.
Historically, it’s been thought that the chance of transmission of monkeypox and variola virus is highest with the current presence of a rash, Isaacs noted. Actually, “the current presence of virus in throat cultures in asymptomatic people was thought to be of little if any epidemiologic importance considering that the successful eradication of smallpox was due partly to the capability to always identify a source patient. However, the existing worldwide monkeypox epidemic and the mode of human-to-human transmission might provide evidence that asymptomatic or preclinical spread may appear.”
Because of this study, Charpentier and colleagues included 213 MSM who visited the Paris clinic from June 5 to July 11 for routine sexually transmitted infection testing. Median age was 38, and 52% were coping with HIV and receiving antiretroviral therapy, with a median of 9 years since diagnosis.
Of the 13 men who tested positive for monkeypox, eight were coping with HIV. All had undetectable HIV-1 viral load, and all had a CD4 T-cell count above 0.500 109 cells/L, except person who had a count of 0.123 109 cells/L.
Charpentier reported relationships with MSD, Janssen, ViiV Healthcare, Pfizer, Gilead, and Theratechnologies. Co-authors reported multiple relationships with industry.
Isaacs reported relationships with the Veterans Health Administration, the NIH, and the National Institute of Allergy and Infectious Diseases.