There are several unusual features about this outbreak. So far, a high number of the cases in the UK and other non-endemic countries are in men who are gay, bisexual, and have sex with men.
Additionally, many of the cases in this outbreak have not presented with the classical clinical symptoms of monkeypox, such as skin lesions and eruptions concentrated on the face and extremities; in cases in this outbreak, the lesions have been more commonly presenting in the genital and peri-anal regions.
This presentation suggests that direct physical contact with lesions during sexual contact is a likely route of transmission. However, monkeypox does not seem to be a sexually transmitted infection as traditionally described. Rather, as David Heymann (London School of Hygiene & Tropical Medicine, London, UK) commented, “It can be classified as an infection that's transmitted by close sexual contact”.

In the UK, for example, guidance has been issued to health-care professionals to control transmission; more than 20 000 doses of the smallpox vaccine Imvanex have been procured for close contacts of people with monkeypox

Global monkeypox outbreak
Venkatesan, Priya
The Lancet Infectious Diseases, Volume 22, Issue 7, 950