Asymptomatic Monkey Pox Virus Infection: a Self-sampling Screening Intervention Adressed to Gay, Bisexual and Other Men Who Have Sex With Men and Trans Women in Spain

Abstract

We aimed to assess the prevalence of asymptomatic cases of monkeypox virus (MPXV) infection among gay, bisexual, and other men who have sex with men and trans women (TW), using a self-sampling strategy. Anal and pharyngeal swabs were tested by MPXV real-time PCR and positive samples inoculated into Vero E6 cells, which were subsequently checked for cytopathic effect (CPE). Seven out 113 participants were MPXV positive (6.19% (95% CI: 1.75%-10.64%)). Five tested positive in pharyngeal swabs, one in anal swab and one in both. Six did not present symptoms recognized as MPXV infection. Three samples were positive for CPE, and showed anti-vaccinia pAb staining by FACS and confocal microscopy. We describe Mpox cases that remain undiagnosed and show reproductive virus despite low viral loads and who might be able to infect others. Restricting testing to individuals reporting Mpox symptoms may not be enough to contain outbreaks.