Monkeypox Vaccination Queue
Monkey pox vaccination queue in Los Angeles, California on August 4, 2022.| Photo: EFE / EPA / ETIENNE LAURENT

Despite an initial focus on transmission through bodily fluids such as saliva and skin contact since the outbreak began in May, it is increasingly clear that the mainstay of apepox transmission is the sex between men.

The first more rigorous suggestion in this direction was made in July by
an article in the medical journal NEJM, which found that 98% of those infected (out of a sample of more than 500 in 16 countries) were gay or bisexual men. However, the journal did not directly assess that the mode of transmission was gender, although the authors expressed suspicion that it was the case in 95% of cases. They found the monkeypox orthopoxvirus in the seminal fluid of a small group of men.

This month, another article about it was published in the medical journal The Lancet. The sample was smaller (181 Spanish patients), but the authors were more thorough in the interviews and in the assessment of viral load by body area. It should be noted that none of the patients have traveled to endemic regions where the virus circulates in wild animals. None of the patients had a history inconsistent with risky sexual activity, and specific lesions were found to be associated with receptive anal or oral sex. Most have rashes caused by the virus concentrated in the genital, oral and anal areas.

a third article in the medical journal BMJ, with nearly 200 patients in London, confirms the pattern: the overwhelming majority are men who have sex with men, and the lesions that transmit the virus were more concentrated in the genital and perianal region.

According to the World Health Organization, three-quarters of global cases of monkeypox are in men between the ages of 18 and 44. This age group is typical of other sexually transmitted diseases in gay and bisexual men. In addition, almost a third of cases are co-occurrences with “classic” sexually transmitted infections. Anogenital and oral lesions, which account for more than 70% of lesions, may reflect not a preference of the virus, but the sites where it first entered each organism. Public health policies aimed at containing the outbreak have yet to be updated based on this evidence.