Uuntil recently, monkeypox it is rarely spread from person to person. In 2005 research declared a cluster of six cases in the Republic of Congo to be “the longest continuous chain of human monkeypox fully documented to date.”
That has changed, to say the least. So far this year, more than 25,000 cases of monkeypox have been recorded in 83 countries – and human-to-human transmission apparently occurs on a large scale.
How does monkeypox spread among humans? Studies are ongoing, and findings about monkeypox transmission may evolve over time. But here’s what the latest science suggests.
Most cases were once linked to infected animals
The first human case of monkeypox was identified in an infant living in the Democratic Republic of the Congo in 1970. according to the World Health Organization (WHO). In the decades since, cases have been relatively rare and often linked to contact with infected animals. United States suffered a small outbreak in 2003with 47 human cases linked to contact with pet prairie dogs.
Things changed in 2017 when there was a rather large outbreak among humans started in Nigeria. Doctors there diagnosed cases among young men who had not been exposed to infected animals and had lesions on their genitals, as NPR reported. Nigerian researchers have published 2019 survey about the outbreak and raised the possibility of sexual transmission, but the theory did not gain much traction at the time. “There is a tendency for people to buckle down [onto] what is tradition, and the tradition is that monkeypox is transmitted from animals to humans,” said study co-author Dr. Dimi Ogoyna, president of the Nigerian Infectious Diseases Society.
Most monkeypox cases in the ongoing outbreak are sex-related
As the current outbreak shows, human-to-human transmission of monkeypox does happen—and sexual activity plays a significant role.
“Right now, most of the transmission is happening on queer and gay sex networks and most transmission occurs through sexual or intimate contact” says Joseph Osmondson, a clinical assistant professor of biology at New York University.
Ogoyna says monkeypox is primarily spread among humans through close skin-to-skin contact — especially with the hallmark of the disease, a blister-like rash. Researchers are still investigating whether people can be asymptomatically contagious, but individuals are considered infectious at least until their rash has completely healed and fresh skin has formed. According to US Centers for Disease Control and Prevention (CDC).
Research on the current outbreak published in July in New England Journal of Medicine, found that of more than 500 monkeypox cases in 16 countries diagnosed as of June, 95% were linked to sexual activity and 98% were among men who have sex with men. In July, WHO Director-General Tedros Adhanom Ghebreyesus advised men who have sex with men to temporarily reduce their number of partners to minimize risk.
Is monkeypox a sexually transmitted infection (STI)?
Any form of skin-to-skin contact—not just sexual activity—can potentially spread monkeypox. As a result, monkeypox is not considered a “traditional” STI, According to Dr. Roy Gulick, chief of infectious diseases at Weill Cornell Medicine and NewYork-Presbyterian. CDC too says monkeypox is not considered an STI.
Most of the cases in the current outbreak have been linked to male sexual activity, but Osmondson says the virus can also spread in environments where there is a lot of close non-sexual contact, such as on sports teams, in spas or in student dormitories.
Can you get a monkey pattern from surfaces?
It is possible to contract monkeypox through exposure to objects, such as clothing or bedding, that have touched the rash of an infected person. In 2018, a healthcare worker in the United Kingdom contracted monkeypox, most likely after touching the bedding of a sick person. according to one study.
But there is little evidence to suggest that “casual” contact often spreads the virus, says Angela Rasmussen, a virologist at the University of Saskatchewan in Canada. “You have to be exposed to enough of a virus to get it,” she says. This may be possible after sleeping in the same bed or sharing a bath towel with an infected person, but it’s much less likely after fleeting encounters like touching a shared doorknob, she says.
As the majority of cases so far have been linked to sexual activity, it is important to communicate that there is a ‘spectrum’ of risk associated with monkeypox, says Dr Müge Cevik, Clinical Lecturer in Infectious Diseases at the University of St Andrews in Scotland. “Every exposure [doesn’t carry equal] risk,” she says. “People really need to know where to be vigilant. For example, reducing a new [sexual] partners may be more useful than cleaning chairs you sit on in a coffee shop.
Is monkeypox airborne?
It is possible to contract monkeypox through exposure to the respiratory fluids of an infected person, but says the WHO which usually requires close, sustained face-to-face contact. Researchers are still studying how often this type of transmission occurs, according to the CDC.
Scientists have demonstrated that it is possible under specific experimental conditions for monkeypox to spread through aerosols or small particles that can remain in the air, but so far there is no convincing evidence to suggest that this happens in real-world conditions outside the laboratory, Rasmussen says . “It’s spread primarily in communities of men who have sex with men, and that really suggests that the primary mode of transmission is direct, prolonged skin-to-skin contact,” she says. If airborne transmission were common, she says, we’d likely see many more cases among people in other demographics.
In the shadow of COVID-19, people are understandably concerned about the potential transmission of monkeypox through aerosols. But “the epidemiology is very different,” says Rasmussen. “These are very different viruses.”
Can children get monkeypox?
More than 80 children around the world have been sick with the virus so far, largely as a result of household transmission. A pregnant person can also pass the virus to her fetus, according to the CDC.
In the 1970s, monkeypox mostly affected young children, but in 2010 the virus was more commonly diagnosed among adults, according to study published in PLOS Neglected Tropical Diseases in February. This is partly due to routine smallpox vaccination (which also protects against monkeypox) ended up eradicating smallpox, the study authors wrote. A few decades ago, only small children were young enough to be born after smallpox vaccination ended. Now a larger part of the population is vulnerable.
Pediatric cases have raised concerns that schools and kindergartens could become monkeypox hotspots. But Ogoyna says that hasn’t happened during the Nigerian outbreaks, which is a promising sign. “I’m not sure it’s something we need to worry about,” he says. “But we have to tread carefully and look for the evidence.”
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