Incidental diagnosis of monkeypox virus infection in patients undergoing STI screening – findings from a study in France.

Objective This study aimed to investigate the prevalence of monkeypox virus (MPXV) infections in the general population consulting for routine STIs in our Marseille public hospital. In fact, recent worldwide MPXV outbreak, mainly impacted men who have sex with men (MSM) and the prevalence of MPXV infections in the general population remains poorly defined. Methods All samples addressed routinely to our microbiological laboratory for STIs between 1 July and 15 October 2022 were screened with MPXV-specific qPCR. Results A total of 2688 samples from 1896 patients suspected of having STIs were tested and eight (0.4%) patients were incidentally diagnosed with MPXV infection, including six men and two women. MPXV was detected in rectal swabs (n=2), urine (n=2), vaginal swabs (n=2), a urethral swab (n=1), and a skin swab (n=1). Conclusion This study suggests that some MPXV infections are likely to be underdiagnosed due to their non-specific clinical presentation and/or insufficient clinical knowledge of the disease. Our data showed that systematic screening was particularly useful for detecting MPXV in patients without classic lesions or cases of asymptomatic carriage in patients reporting recent high-risk exposure, but also in patients presenting no obvious risk factor.