Retrospective detection of asymptomatic monkeypox virus infections among male sexual health clinic attendees in Belgium
Irith De Baetselier, Christophe Van Dijck, Chris Kenyon, Jasmine Coppens, Johan Míchiels, Tessa de Block, Hilde Smet, Sandra Coppens, Fien Vanroye, Joachim J. Bugert, Philipp Girl, Sabine Zange, Laurens Liesenborghs, Isabel Brosius, Johan van Griensven, Philippe Selhorst, Éric Florence, Dorien Van den Bossche, Kevin K. Ariën, Antônio Mauro Rezende, Koen Vercauteren, Marjan Van Esbroeck, for the ITM Monkeypox study group, Kadrie Ramadan, Tom Platteau, Karin Van Looveren, Jolien Baeyens, Cindy Van Hoyweghen, Marianne Mangelschots, Leo Heyndrickx, Anne Hauner, Betty Willems, Emmanuel Bottieau, Patrick Soentjens, Nicole Berens‐Riha, Saskia van Henten, Stefanie Bracke, Thibaut Vanbaelen, Leen Vandenhove, Jacob Verschueren, Kevin K. Ariën, Marie Laga, Jef Vanhamel, Béa Vuylsteke
Abstract
The magnitude of the 2022 multi-country monkeypox virus (MPXV) outbreak has surpassed any preceding outbreak. It is unclear whether asymptomatic or otherwise undiagnosed infections are fuelling this epidemic. In this study, we aimed to assess whether undiagnosed infections occurred among men attending a Belgian sexual health clinic in May 2022. We retrospectively screened 224 samples collected for gonorrhea and chlamydia testing using an MPXV PCR assay and identified MPXV-DNA-positive samples from four men. At the time of sampling, one man had a painful rash, and three men had reported no symptoms. Upon clinical examination 21-37 days later, these three men were free of clinical signs, and they reported not having experienced any symptoms. Serology confirmed MPXV exposure in all three men, and MPXV was cultured from two cases. These findings show that certain cases of monkeypox remain undiagnosed and suggest that testing and quarantining of individuals reporting symptoms may not suffice to contain the outbreak.