Role of Direct Sexual Contact in Human Transmission of Monkeypox Virus, Italy

• Published in: Emerging infectious diseases Vol. 30; no. 9; pp. 1829 - 1833
• Main Authors: Sberna, Giuseppe, Rozera, Gabriella, Minosse, Claudia, Bordi, Licia, Mazzotta, Valentina, D'Abramo, Alessandra, Girardi, Enrico, Antinori, Andrea, Maggi, Fabrizio, Lalle, Eleonora
• Format: Journal Article
• Language: English
• Published: Centers for Disease Control and Prevention 01.09.2024
• Subjects: monkeypox virus; mpox; MPXV; Role of Direct Sexual Contact in Human Transmission of Monkeypox Virus, Italy; sexual contact; viruses; zoonoses
• ISSN: 1080-6059; 1080-6040; 1080-6059
• DOI: 10.3201/eid3009.240075

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.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.