The 2022 global mpox outbreak was driven by human-to-human transmission, but modes of transmission by sexual relationship versus sexual contact remain unclear. We evaluated sexual transmission of mpox by using monkeypox virus (MPXV) G2R-mRNA as a marker of ongoing viral replication through in vitro experiments. We analyzed clinical samples of 15 MPXV-positive patients in Italy from different biological regions by using the setup method. The presence of MPXV DNA, MPXV G2R-mRNA, or both in all analyzed lesion swab samples, independent of viral load, confirmed a higher infectivity risk from skin lesions. Positivity for MPXV G2R-mRNA in nasopharyngeal swabs was associated with high MPXV load, whereas positive results for MPXV G2R-mRNA were obtained only in the 2 semen samples with the lowest MPXV loads. Our results suggest that close or skin-to-skin contact during sexual intercourse is the main route of sexual transmission and that semen is a minor driver of infection, regardless of MPXV load.

2022 年全球 MPOX 爆发是由人际传播驱动的，但性关系与性接触的传播方式仍不清楚。我们通过体外实验使用猴痘病毒 (MPXV) G2R-mRNA 作为持续病毒复制的标记来评估 MPOX 的性传播。我们使用设置方法分析了意大利来自不同生物区域的 15 名 MPXV 阳性患者的临床样本。在所有分析的病变拭子样本中，MPXV DNA、MPXV G2R-mRNA 或两者的存在（与病毒载量无关）证实了皮肤病变具有较高的感染风险。鼻咽拭子中 MPXV G2R-mRNA 的阳性与高 MPXV 载量相关，而 MPXV G2R-mRNA 的阳性结果仅在 MPXV 载量最低的 2 份精液样本中获得。我们的研究结果表明，性交过程中的密切接触或皮肤接触是性传播的主要途径，而精液是感染的次要驱动因素，无论 MPXV 载量如何。