Public health experts are pointing to the past epidemics as examples to help explain why monkeypox isn't a sexually transmitted infection — at least not by the classic definition.

Ebola had plagued Africa for decades while being overlooked by most of the world with regard to resources and research. In 2013, the long-known virus flared up, creating a global emergency.

New international attention created increased scrutiny, and it soon became clear that transmission involved sex. Ebola chiefly spreads because of direct contact with infected bodily fluids but occasionally moves between people via semen.

A similar story can be told about the Zika virus — it is mostly carried between people by mosquito bites but has also been transmitted by genital fluids. Neither Ebola nor Zika are typically listed as STIs — by the World Health Organization, the Centers for Disease Control and Prevention and the National Institutes of Health.

Now, as monkeypox spreads in the U.S., health experts are trying to tackle similar misconceptions about how this virus spreads.

Globally, the WHO has recorded sexual transmission in 91% of cases this year — but that leaves about one in 10 infections spreading non-sexually. The global health agency also says that transmission via skin-to-skin contact during sex and bodily fluids cannot currently be “disentangled.”

“We have many diseases that can be transmitted sexually, but that's not necessarily the only route,” said Dr. Leslie Kantor, professor and chair of the department of urban global public health at the Rutgers School of Public Health. “And then those are not considered sexually transmitted infections.”

But the STI label can also be empowering, health experts said.

It can help at-risk groups to spend more thought on making informed decisions about their sexual activity. Given that many people in New York City seem to be getting the virus through sexual or intimate contact so far, public health officials have started to caution against risky sexual behavior. The STI label can also come with greater access to health care, such as free testing.

This chart shows the transmission type for 5,314 of 23,286 (22.8%) monkeypox cases, where such data are available worldwide as of August 8, 2022.


Gothamist spoke with more than a half-dozen epidemiologists, professors of medicine and health care policy experts to address the fundamental question of whether monkeypox should be considered an STI and other unknowns circulating around the orthopoxvirus.

Kantor and others say, biologically speaking, there isn’t enough evidence yet to label monkeypox as an STI — despite the majority of cases recorded so far being linked to sexual activity among gay and bisexual men and trans people.

“Sexually transmitted infections are defined as such because their primary route of transmission is sexual,” Kantor said, meaning it is driven by sexual fluids or lesions on the genitals. But monkeypox has long been known to spread via skin-to-skin contact away from private areas — and continues to do so in this year's outbreak.

She, other disease researchers and physicians said preemptively labeling monkeypox as an STI could also downplay the threat posed to the general public, leading some people to not take precautions when they should. The WHO and federal, state, and city officials have recently declared public health emergencies over the 2022 monkeypox outbreak. As of Monday, about 1,900 cases had been reported in New York City — alongside just over 28,000 globally.

The danger in labeling something like monkeypox as a sexually transmitted infection is that a lot of people switch off.
Dr. Matthew Hamill, Johns Hopkins University School of Medicine

“The danger in labeling something like monkeypox as a sexually transmitted infection is that a lot of people switch off,” said Dr. Matthew Hamill, an infectious disease professor at the Johns Hopkins University School of Medicine who is actively treating monkeypox patients. “Because they think, ‘well, that's nothing to do with me. That doesn't apply to me.’”

Part of the concern centers around overemphasizing the early connection between monkeypox and the LGBTQ community. As Gothamist reported last week, viruses are opportunists. Monkeypox sparked the ongoing outbreak by happening to make its way into this community via sexual contact.

Hamill and others said this situation might have set up a self-fulfilling narrative: If early studies and medical exams focused on looking for signs of monkeypox sexual transmission, then that’s what they’re mostly going to find.

An oft-cited New England Journal of Medicine study, for example, looked at cases across 16 non-African countries from early in the outbreak. That study found most of the rashes — 73% — occurred in the genital area. The opposite was found by a CDC study published last week. It looked at cases reported later in the U.S. outbreak — and found most (53%) did not have rashes on the genitals. Both studies examined hundreds of infections — more than 90% found in gay or bisexual men and contracted through sexual activity.

“Overwhelmingly, [monkeypox] is being spread through sexual networks of men who have sex with men,” New York State Health Commissioner Dr. Mary Bassett told WNYC’s Brian Lehrer Show on Monday. “But we know enough to know that it won't stay that way.”

Biologically speaking, what defines an STI?

Earning the STI label requires more than merely detecting monkeypox in genital fluids, as in a study published last week in The Lancet Infectious Diseases.

If this were the only bar for entry, then the coronavirus would qualify, and no one reputable claims that COVID-19 is sexually transmitted.

The WHO and the NIH’s National Library of Medicine define a sexually transmitted infection as a microbe — virus, bacteria, or parasite — whose “usual” or “predominant” mode of spreading is sex.

The key word there is predominant, Hamill said. Some STIs can pass without coitus — such as HIV through blood transfusions or pregnancy — but for the most part, they’re transmitted by either vaginal, anal, or oral sex.

“How does one define the primary mode of transmission? Does it have to be 99%? 98%? It’s a little arbitrary,” Hamill said. But he added that the majority of cases of Zika that we see worldwide are not because of sexual contact between two people, whereas the majority of syphilis is.

Monkeypox isn’t even the first virus in its family thought to sometimes pass through sexual contact. The spread of vaccinia virus, a less dangerous cousin of smallpox that’s used to make vaccines, has also been tied to sex — but it’s not considered an STI.

All that said, sexual health precautions — such as wearing condoms and limiting partners — can help tame monkeypox and its outcomes.

“We want to recommend things like condoms right now. It's very, very painful to get these lesions or get this rash on the genitals,” Kantor said. “So even if people are mostly being infected from rubbing skin to skin, what you don't want is a lesion on the penis, on the anus, in your mouth.”

Hamill said viruses like monkeypox, Ebola, and Zika might be better served by a new term: sexually associated infection.

“It just recognizes that they can be transmitted through sexual contact but also through other means,” he said.

Does monkeypox spread through casual contact?

People are unlikely to catch monkeypox just walking by an infected person — but that doesn’t mean somebody can completely rule out all types of casual interactions.

Anyone can get monkeypox, given it’s known to transmit via direct physical contact with bodily fluids or skin lesions that can form all over the body, experts said. This mode of transmission is thought to require prolonged touching or contact between individuals, especially when a person’s skin has abrasions.

It’s understandable, then, how sex would be implicated, given the rubbing and friction between skin.

But monkeypox lesions themselves exude fluids, and skin abrasions can be microscopic — caused by something as simple as scratching your skin. Of the 1,300 global cases with reported exposure locations, about one in five have involved parties and large events with no sexual contact, WHO data shows.

This chart shows the exposure locations for 1,236 of 23,286 (5.3%) monkeypox cases, where such data are available worldwide as of August 8, 2022


“Intimate contact is not the only way it can be transmitted,” said Dr. Danielle Ompad, an epidemiology professor at the NYU School of Global Public Health. “It could also be transmitted if you and I were sitting next to each other on a train from New York to D.C. You had a lesion on your arm, I'm sitting next to you, and our arms are touching for a prolonged period of time.”

Hyperfocusing on sexual organs also understates other ways the virus can enter the body — such as via the eyes or mouth.

“If you are infected, you do want to be really, really careful about touching the rash and touching another part of your body,” Kantor said, citing a recommendation she saw for infected patients not to use contact lenses. “You don't want to get this virus in your eye... Once somebody's infected, they can actually move the infection to other parts of their own body.”

The WHO describes large respiratory droplets as a way to catch monkeypox.

The droplets need close intimacy, such as a deep kiss, to spread monkeypox. This isn’t like the coronavirus, which can transmit over the length of a poorly ventilated room. In this way, monkeypox mirrors a handful of other STIs — such as herpes and human papillomavirus — that are thought to be spread by open-mouth kissing.

But the WHO also says contaminated materials like linens, bedding, clothes, and electronics can pass the monkeypox virus.

If droplets or fluids get on a person’s hands, it’s thought that they can infect themselves by touching the mouth or their mucous membranes, such as the eyes. And studies show the average person touches their eyes, mouth and face about 50 times per hour.

In her interview with the "Brian Lehrer Show," Bassett, the state health commissioner, said city dwellers don’t need to worry about common surfaces such as communal bikes. The monkeypox virus and its close relatives are thought to remain infectious on fabrics for weeks to months — but typically in cool, dark places with low humidity.

But if a New Yorker is concerned, they can just wipe down the bike handlebar with sanitizer, she said.

“You might feel that way just in general,” Bassett said.

Would the STI label get people better access to health care?

Even though monkeypox has not been classified as an STI, it’s important for policymakers to recognize that sexual health clinics have been at the forefront of the response so far and may need additional resources, said Joshua Michaud, associate director of global health policy at the KFF, an organization that provides health policy analysis.

He said that has to do, in part, with the fact that monkeypox sometimes presents like an STI, with lesions appearing on the genitals. Sexual health clinics also offer a certain degree of discretion and anonymity for those who don’t want to go to their primary care doctor, he noted.

“At the same time, there has been an increase in sexually transmitted infections, generally, in the United States,” Michaud said. “So without additional support being directed to those clinics, it's going to be very, very difficult to address [monkeypox].”

The Affordable Care Act requires most health plans to provide free STI screenings and counseling without patient cost sharing.

The Affordable Care Act requires most health plans to provide free STI screenings and counseling without patient cost sharing. But Michaud said the federal government’s recent decision to declare monkeypox a public health emergency would likely make a bigger difference in access to and funding for care than officially deeming it an STI.

The emergency declaration “does open up flexibility for the federal government to direct new funding and institute new types of waivers for different types of programs,” Michaud said.

As far as coverage, there’s the possibility that the federal government could use the public health emergency to try to make monkeypox testing and treatment free for patients through a mix of federal funding and insurance mandates, the way it did for COVID-19. The declaration also clears a path for the U.S. Food and Drug Administration to consider emergency authorization for potential monkeypox treatments.

Does talking about STIs create monkeypox stigma — or reduce it?

Dr. Edward W. Hook, who has studied STIs for more than 40 years, said the U.S. has a habit of openly judging people’s sexual habits — while also shying away from open discussions about STIs.

“Monkeypox is emblematic of a long-standing, really singular American prudishness, which has hampered and continues to hamper efforts to control STIs,” said Hook, emeritus professor of infectious diseases and epidemiology at the University of Alabama at Birmingham and a scientific adviser to the American Sexual Health Association.

He and other experts interviewed for this story said people shouldn’t ignore the links between monkeypox and sexual activity. Even if the academic discussion is still open on whether the virus spreads via genital fluids (and to what degree), it’s obviously still tied to intimate behavior.

“We do not want a situation where people are stigmatized because of this condition or because public health professionals are worried about stigmatizing people,” said David Harvey, executive director of the National Coalition of STD Directors.

The danger of stigma, they said, comes from only referencing sex and LGBTQ communities when discussing the transmission of monkeypox. In New York City, about 3% of cases have happened in people who identify as straight, and nearly 30% didn’t list their sexual orientation.

Colorized transmission electron micrograph of monkeypox virus particles (red) cultivated and purified from cell culture.


On the flip side, Harvey said health providers seem almost afraid to discuss the sexual implications of monkeypox. He said part of the issue might stem from the CDC running its monkeypox response through its office of animal-borne, or zoonotic, diseases rather than through its STI division. It could be creating a trickle-down effect with health providers.

“They're avoiding some of the frank, direct language that we need to have, and they're avoiding using the term sexually transmitted infection,” Harvey said.

He, Hamill and others said the debate on whether monkeypox is an STI also distracts from more serious issues, such as funding for prevention programs.

“[Monkeypox] has really exposed the pre-existing cracks in a very strained public health system,” Hamill said, citing the broad divestment in STI programs in recent years even as rates of these infections rise nationwide.

A 2020 report from the National Academies of Sciences, Engineering, and Medicine found that federal funding for STI prevention and control had remained flat for nearly two decades — at about $160 million annually. After adjusting for inflation, the trend represented a 40% reduction in funding.

Meanwhile, the total lifetime direct medical costs of treating STIs amount to nearly $16 billion, the report said. The analysis added that the Trump administration closed STI clinics when in 2019, it placed restrictions on family planning centers that also provide abortion services.

“Participating sites fell from 4,515 in 2009 to approximately 3,825 in 2019,” the report said. The policy was reversed last year by the Biden administration. Harvey said monkeypox offers a chance to spotlight STI prevention.

“This is an opportunity to fix that and allocate money for STI clinical services,” he said.

*Some health groups refer to STIs as the infectious agents (example: HIV), while sexually transmitted diseases, or STDs, are the resulting bodily outcomes (example: AIDS). That's because some infections never develop into diseases in certain people, such as silent carriers of human papillomavirus. STI is also believed to generate less stigma. But health agencies like the CDC, WHO, and others often use STI and STD interchangeably.

This story has been updated to correct a quote from Dr. Matthew Hamill. Hamill later told Gothamist he meant a "strained" public health system, not a "strange" public health system.