When Christian Hoffmann explains to doctors at training courses these days how they can recognize a monkeypox infection in their patients, he actually only ever shows pictures. “You often have to look for the smallpox. Sometimes it’s just one that looks like a small pimple, sometimes just a reddening,” says Hoffmann. Almost no urologist or dermatologist in Germany would think of monkeypox in something like this. “It is so important that doctors now have the disease on their cards.” Hundreds of huge smallpox spread all over the body, that is rather the exception.
Christian Hoffmann is an internist and HIV specialist at the Infectious Diseases Center Hamburg (ICH), one of the largest centers for the treatment of infectious diseases in Germany. Recently, more and more patients have been coming to him and his colleagues because they fear they have contracted monkeypox. They have already registered more than 60 confirmed cases at the ICH. The Robert Koch Institute (RKI) has already reported more than 1,300 cases nationwide . And on average, their number has roughly doubled every week recently. Only the UK and Spain report similarly high numbers.
“If we don’t do something soon, I think we’re heading for quite a wave,” says Hoffmann. The general population will probably not be affected as much. “But for the community, that could mean a high burden of disease.”
The community, by which Hoffmann means men who have sex with men, MSM for short. Although the monkeypox virus can infect anyone through close contact, the current outbreak is spreading predominantly among MSM, particularly those who have sex with multiple partners. In the UK, 321 of the 813 people proven to be infected as of June 22 filled out a questionnaire. 96 percent said they were gay, bisexual, or men who have sex with men . MSM simply describes the fact that men have sex with men, regardless of how they identify themselves.
So far, all cases of monkeypox at the ICH in Hamburg have been MSM. It looks very similar in other German cities, says Hoffmann. He knows this because he is currently merging the data from large German infectious disease centers and is planning a publication with several hundred cases. The fact that the virus has so far spread primarily in the MSM community is tricky for combating the outbreak. The danger of stigmatization is always there .
Nevertheless, say experts, the situation must be clearly stated. “Currently, almost one hundred percent of transmissions are through sex among men. You make a mistake if you don’t say it clearly,” says Gerd Fätkenheuer, head of clinical infectiology at Cologne University Hospital. This is the only way to reach the right people with information.
Individuals with a large number of contacts are sufficient for the spread
But how does this rapid transmission in a specific group come about in the first place? “The outbreak could have something to do with the fact that the virus established itself in the MSM network for the first time,” says Sebastian Funk.
Funk has modeled the spread of the virus with his colleagues from the London School of Hygiene and Tropical Medicine to understand what is behind the current outbreak, with hundreds of cases, that the UK is experiencing ( MedRxiv : Endo et al., 2022 ). He and his colleagues used survey data on how many intimate contacts MSM and heterosexual people have. They fed the model they created various assumptions about the likelihood of transmission of monkeypox through sex.
The result: Even a few transmissions among men who have had sex with men can lead to the outbreak of greatness that the UK and other countries are experiencing right now. A few people are probably enough, but they each have a lot of sexual contacts, so that the number of reproductions is greater than one, so the outbreak is growing.