Sperm can play a role in mpox infection, according to findings by a research team in Frankfurt. “Our results offer an explanation for why sexual contact carries a particularly high transmission risk,” said doctoral student Emma Torbica, who carried out the experiments. “Semen can promote infection when it comes into contact with anal or genital mucous membranes where pox lesions have already formed but were not yet noticeable.”
Mpox is primarily transmitted from animals to humans, but newer variants can also spread from person to person. The researchers say the illness is usually mild with rather nonspecific symptoms. “Only later do the characteristic pox lesions appear on the skin,” they noted. “When the first symptoms appear, those infected are contagious, but transmission requires close contact, such as a mother hugging her child or through sexual contact.”
Semen promotes uptake of the pathogen
The study team from Goethe University and University Medical Center Frankfurt examined which factors might boost spread. To do this, scientists infected connective tissue cells and epidermal skin cells with mpox virus. “If the viruses had previously been mixed with semen, it increased the virus’s uptake by the cells,” the press release stated.
The cause appears to be naturally occurring protein fragments in semen that form fibers and thus facilitate the mpox virus docking to human cells. The findings are important for clinical practice, said study leader Denisa Bojkova. An experimental compound could disrupt these structures and additionally directly inhibit the virus. “In the long term, this could open up new avenues for prevention.”
Cases persist in Germany as well
In Germany, new mpox cases continue to appear at comparatively low levels. The Berlin state health authority, Landesamt für Gesundheit und Soziales (Lageso), recently reported that mpox is increasingly being transmitted through sexual activity between men and women. The agency noted several cases in the context of sex-positive events for heterosexual and queer people.
In general, infections have mainly affected men who have sex with men and who often change sexual partners. For this group, Lageso recommends vaccination. The vaccination is described by the Robert Koch Institute as very effective and well tolerated. Even if someone contracts mpox after vaccination, the illness is usually much milder.
