 The study assessed the prevalence of monkeypox virus in high-risk populations, including gay, bisexual and other men who have sex with men, GBMSM, trans women, TW, and non-binary people without symptoms or with unrecognized monkeypox, Mpox symptoms, using a self-sampling strategy. Seven participants were MPXV positive, five tested positive in pharyngeal swabs, one in anal swab and one in both. Three samples were positive for cytopathic effect and showed anti-vaxinia PAB staining by FACS and confocal microscopy. This suggests that unrecognized Mpox cases can shed infectious virus and restricting testing to individuals reporting Mpox symptoms may not be sufficient to contain outbreaks. This article was authored by Christina Augusti, Hector Martinez-Riveros, Aguida Hernandez Rodriguez, and others.