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

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. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement This work was supported by the Ministry of Health of Government of Catalonia (Spain) [no grant number] and Hoffmann-La Roche Laboratories. NI-U is supported by the Spanish Ministry of Science and Innovation (grant PID2020-117145RB-I00), EU HORIZON-HLTH-2021-CORONA-01 (grant 101046118) and by institutional funding from Grifols, Pharma Mar, HIPRA, Amassence and Palobiofarma. Finally, the authors thank the CERCA Programme/Generalitat de Catalunya for their support of the Germans Trias i Pujol Research Institute (IGTP). ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: The Ethical Committee of the Germans Trias i Pujol Hospital approved the study protocol (PI-22-195). I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines and uploaded the relevant EQUATOR Network research reporting checklist(s) and other pertinent material as supplementary files, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors