Since the outset of the global monkeypox outbreak in May, public health and infectious disease experts have told the public that the virus is largely transmitted through skin-to-skin contact, in particular during sex between men.
Now, however, an expanding cadre of experts has come to believe that sex between men itself — both anal as well as oral intercourse — is likely the main driver of global monkeypox transmission. The skin contact that comes with sex, these experts say, is probably much less of a risk factor.
In recent weeks, a growing body of scientific evidence — including a trio of studies published in peer-reviewed journals, as well as reports from national, regional, and global health authorities — has suggested that experts may have framed monkeypox’s typical transmission route precisely backward.
Reconceiving the primary risk factors for transmission is crucial because of how it may affect guidance on reducing the risk of infection, including the question of whether demanding that people with the virus self-isolate has any substantial impact on transmission.
“A growing body of evidence supports that sexual transmission, particularly through seminal fluids, is occurring with the current MPX outbreak,” said Dr. Aniruddha Hazra, medical director of the University of Chicago Sexual Wellness Clinic, referring to monkeypox and to recent studies that found the virus in semen.
Consequently, scientists told NBC News that the Centers for Disease Control and Prevention and other public health authorities should update their monkeypox communication strategies to more strongly emphasize the centrality of intercourse among gay and bisexual men, who comprise nearly all U.S. cases, to the virus’ spread.
On Aug. 14, Dr. Jeffrey Klausner, an infectious disease physician at the University of Southern California, and Dr. Lao-Tzu Allan-Blitz, a resident physician in global health at Brigham and Women’s Hospital in Boston, published an essay on Medium in which they reviewed the science supporting the argument that during the current outbreak, monkeypox is largely transmitting through anal and oral intercourse between men.
“It looks very clear to us that this is an infection that is transmitting sexually the vast majority of the time,” Allan-Blitz said. This debate, however, is far from settled. Dr. Rosamund Lewis, technical lead for monkeypox at the World Health Organization, told NBC News it was “unfortunate but true” that “we don’t know yet” whether the virus is predominantly transmitted through intercourse.
“Completely reading the situation as uniquely due to anal or oral sex is highly likely to be overreach,” she said. “The correlation may appear to be strong, but that does not explain the whole picture of disease caused by this virus. So we need to keep an open mind.”