Since the beginning of the global monkeypox epidemic, public health and infectious disease experts have told the public that the virus is transmitted primarily through skin-to-skin contact, particularly through sexual intercourse between men.
Now, however, a growing body of experts believe that male-to-male sex itself—both anal and oral—is a key driver of the global transmission of monkeypox. According to these experts, skin-to-skin contact is probably a greater risk factor.
A growing body of scientific evidence in recent weeks — including three studies published in peer-reviewed journals, as well as reports from national, regional and global health authorities — suggests experts may have reversed the typical transmission route of monkeypox.
Re-examination of key risk factors for transmission is important because of how it may affect guidelines for reducing the risk of infection, including the question of whether requiring self-isolation of people infected with the virus has a significant impact on transmission.
“Increasing evidence supports the current epidemic of MPX transmission, particularly via seminal fluid,” said Dr. Aniruddha Hazra, medical director of the University of Chicago’s Sexual Health Clinic, cited recent research that found monkeypox and the virus in semen.
Therefore, scientists told NBC News that the Centers for Disease Control and Prevention and other public health agencies should update their monkeypox communication strategies, emphasizing more strongly the centrality of sex between gay and bisexual men, who account for nearly all US cases. to spread
August 14, Dr. Jeffrey Klausner, an infectious disease physician at the University of Southern California, and Dr. Lao-Tzu Allan-Blitz, MD, 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 monkeypox during the current outbreak is mostly transmitted through anal and oral sex. between men
“It’s very clear to us that it’s often a sexually transmitted infection,” Allan-Blitz said.
However, this dispute has not been resolved.
Dr. Rosamund Lewis, the World Health Organization’s technical director for monkeypox, told NBC News that “we don’t know yet” whether the virus is mostly sexually transmitted.
“To read the condition as entirely specific to anal or oral sex may be overkill,” he said. “The correlation may appear strong, but it does not explain the full picture of disease caused by this virus. So we have to be open-minded.”
Some infectious disease experts see evidence to support the argument that monkeypox is at least sexually transmitted.
“At this point,” said Dr. Paul Adamson, an infectious disease specialist at the UCLA School of Medicine, said, “I don’t know if we can call it sexual transmission, not skin-to-skin contact. during this moment. However, emerging evidence suggests that monkeypox may be more sexually transmitted.
analysis of evidence
In an interview with Klausner, who submitted his and Allan-Blitz’s scientific journal version, he said the evidence supports the global hypothesis that sex itself ignites four key points.
First, he noted, according to the WHO, more than three-quarters of cases of monkeypox are among men between the ages of 18 and 44. That’s a typical age cutoff for sexually transmitted infections among gay and bisexual men, he said. In addition, in recent studies of combined monkeypox in this demographic, 17% to 32% of those diagnosed with the virus had a concurrent sexually transmitted infection (STI) diagnosis.
Second, during the global epidemic, the atypical monkeypox cases historically seen in 11 African countries where the virus has been endemic since its first identification in humans in 1970, occurred mostly in the genital and anorectal regions of men. This, experts told NBC News, shows that these are the sites where the virus first entered the body.
In a study of 197 cases of monkeypox in London men published July 28 in The BMJ, a journal of the British Medical Association, researchers found that 56% had lesions in the genital area and 42% in the anorectal area. And in a study published July 21 in The New England Journal of Medicine, a global team of researchers pooled 538 cases of monkeypox and found that 73% of them were in the genital or anorectal areas.
Third, the researchers found monkeypox in the semen, suggesting that the virus can be transmitted through ejaculation. Also, the authors of two recent studies detected the virus in rectal swabs from men who had monkeypox but were asymptomatic, suggesting that the virus can be transmitted from the anorectal region before symptoms develop in humans. According to experts, research is needed in both directions.
Referring to body fluids such as semen, vaginal fluids and blood, WHO’s Lewis said: “Research is ongoing to learn more about whether humans can transmit monkeypox through the exchange of these fluids during and after symptomatic infection.”
Finally, Klausner noted that scientists have found a link between certain sexual acts and the location of monkeypox lesions.
Authors of the article published in August. The Lancet, which documented 181 cases of the virus in Spain, reported on December 8 that 38% of men who reported having had anal sex developed proctitis, or prostatitis. Only 7% of men who reported having sex with men experienced this potentially excruciating symptom. Additionally, 95% of men with tonsillitis reported having had oral sex with a man.
Dr. Oriol Mitja, an associate professor of infectious diseases at Trias y Pujol University Hospital in Spain and co-senior author of the study in The Lancet, said monkeypox is most effectively transmitted by contact with mucosa in the anorectal region. , genitals, mouth and throat.
Monkeypox is more likely to be transmitted through oral or anal sex than through skin-to-skin contact, which requires some kind of defect, such as a wound, to allow the virus to enter, Mitja said.
Dr. Dimi Ogoyna, a professor of medicine and infectious diseases at the Niger Delta University in Nigeria, acknowledged Mitja’s research supporting the link between sex between men and monkeypox.
“This does not mean that women or heterosexuals are not at risk of monkeypox or that the mucous membrane of the female genitalia is not exposed to abrasion during intercourse,” Ogoyna said.
Some experts, such as WHO’s Lewis, argue that the main way monkeypox is transmitted is through skin-to-skin contact, including during sex. Others, like Klausner and Adamson, believe that sex is the main driver of the current outbreak, infectious disease experts say, because monkeypox hasn’t spread like this in decades.
“Historically, the main route of transmission of monkeypox was through skin-to-skin contact, but in previous outbreaks it could have been sexually transmitted. It will take some time and more data to disprove our understanding of driving,” Adamson said.
According to the CDC, 38,019 people in 93 countries have been diagnosed with monkeypox during the current global outbreak. And according to the World Health Organization, 97% are diagnosed in gay, bisexual and other men who have sex with men. The consistency Some experts argue that this demographic remains so prevalent that the virus is transmitted among them through group-specific behaviors – anal sex and male-to-male oral sex.
At the same time, the virus in a global epidemic follows the same transmission patterns as in Africa. But experts say that when the virus is transmitted non-sexually, as in those African nations, the efficiency is low and the relatively slow spread seen in Africa is strikingly similar.
Specifically, the authors of The New England Journal of Medicine found that only 0.8% of the cases they analyzed were from non-sexual intimate contact and 0.6% were from domestic contact. However, 95% of these cases can occur during sexual intercourse between men. The authors of the Lancet paper estimated that 3% of the cases they analyzed were through non-sexual domestic contacts.
Dr. Monica Gandy, an infectious disease physician at the University of California, San Francisco, said a small number of cases of monkeypox in children can be transmitted through hugging or hugging. It has shown that, in rare cases, it can also be transmitted non-sexually, including various STDs.
“STDs such as syphilis or chancroid are common in children in tropical areas where their hands and feet are shaved,” Mitja said.
Referring to the recent rapid expansion of the global epidemic, Ogoyna said: “It’s all about numbers – the more sexual partners, the more likely to be exposed.”
If monkeypox is mostly sexually transmitted and rarely transmitted, these severe public health guidelines recommend isolating people with the virus for the duration of the disease, which can last several weeks, Mitja and her coauthors said in their paper.
Klausner, for updated communications from the CDC and other health authorities, emphasized the importance of sex for the transmission of monkeypox.
“If we accept that it’s spreading like this, then we know how to reduce the spread: awareness and education and encouraging people to have sex with multiple partners until they get vaccinated,” Klausner said. Reduce behavior, try to use condoms.
CDC spokeswoman Kristen Nordlund said of the agency’s latest analysis, “The majority of cases of monkeypox diagnosed in the United States involve sexual and intimate contact, which can involve a range of behaviors.” Additional analyzes are needed to understand whether specific sexual and intimate behaviors that occur during intercourse contribute disproportionately to prevalence.
Professor Lao-Tzu Allan-Blitz of Harvard University has expressed concern that telling the public that monkeypox is sexually transmitted among gays will fuel homophobia. But keeping quiet about how the virus is transmitted comes at a price, he says: It prevents people from understanding how best to protect themselves.
“If we remain silent, we can also do harm,” he said.
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