The vast majority of recent cases of monkeypox have been transmitted through sexual contact, according to the largest study to date, which also shows that the vast majority of those affected were gay men.

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This study, published Thursday in the scientific journal New England Journal of Medicine, analyzed data from more than 520 cases in 16 different countries (Canada, United States, Europe, etc.), spread over two months between the end of April and the end of June.

In total, according to the doctors who treated these cases, 95% resulted from sexual contact.

“It is important to emphasize that monkeypox is not a sexually transmitted infection in the traditional sense; it can be caught by any close physical contact” with an infected person, said the study’s lead author, John Thornhill. “But our work suggests that the majority of transmission so far is linked to sexual activity. »

The skin lesions observed, mainly anal, on the genitals or the mouth, could represent the zones of inoculation, notes the study.

Semen analysis of 32 people showed the presence of virus DNA in 29 cases, but further studies are needed to determine whether transmission can indeed take place by this route.

In total, 98% of the cases studied were gay or bisexual men. The median age was 38 years old.

Nearly 41% were infected with HIV, the AIDS virus, but the vast majority of them were on treatment.

No deaths were recorded among the cases studied, and most were mild cases.

Despite everything, 13% were hospitalized. The main reasons were pain in the anorectal region, or skin infections. But no serious complications were subsequently observed.

In 23 people with a clear history of their infection, the incubation period (before the first symptoms appeared) was one week — but could range from 3 to 20 days.

As previously reported, the study highlights that the symptoms observed differ from those usually seen in African countries where the disease is endemic.

Especially the fact that the rashes are concentrated in certain areas. Lesions were observed in 95% of people, including the genito-anal area in 73% of cases.

The number of lesions varied greatly from person to person, but was generally less than 10.

The authors thus warn of the risk of misdiagnosing, thinking they are dealing with a sexually transmitted infection.