Mpox virus and transmission through sexual contact: Defining the research agenda

A multicountry outbreak of mpox (formerly monkeypox) in 2022 has affected gay, bisexual, and other men who have sex with men disproportionately, highlighting the need to understand the role of sexual contact in transmission.• While mpox virus (mpoxv) is not a novel pathogen and has been circulating in subsaharan Africa for many years, sexual transmission has not been well described.• Epidemiological, clinical, and virological data indicate that transmission of mpoxv through sexual contact, both penetrative and nonpenetrative, is more effective than transmission through casual skin-to-skin contact.• This article addresses many remaining questions about factors associated with the sexual route of mpoxv transmission and provides a framework within which research studies can be prioritised to guide policy and prevention needs.A multicountry outbreak of mpox (formerly monkeypox) was first identified in Europe in May 2022 [1].The number of new cases peaked in mid-August, followed by a rapid decline, which has continued in most affected countries.Countries with the largest numbers of cases have previously reported either no cases or sporadically imported cases from countries with endemic circulation.The outbreak has remained almost exclusively in social and sexual networks of gay, bisexual, and other men who have sex with men (GBMSM), raising many questions about the role of sexual contact in mpox virus (mpoxv) transmission.Many pathogens can be transmitted during sexual contact, mainly through genital fluids during sexual intercourse or through contact with skin or mucosal lesions.Mpox can be described as sexually transmissible, meaning that transmission can occur during a sexual encounter, with or without penetrative sexual intercourse.We do not address the question of whether mpox should be called "a sexually transmitted infection" (STI) or "a sexually transmitted disease" because those terms are inconsistently defined or applied in the literature.