On November 28 2022 the World Health Organization (WHO) advised replacing the term “monkeypox” with “mpox” to avoid language that could be perceived as racist or stigmatizing. Both names will be used for a year while WHO gradually phases out “monkeypox.”
- Mpox is mainly transmitted through close person‑to‑person contact.
- The virus can spread via direct contact with sores and bodily fluids from infected individuals.
- Scientists are investigating additional routes, such as semen, vaginal fluids, and respiratory droplets.
Health authorities have long recommended steering clear of close contact with infected people and contaminated items. However, the current global outbreak has prompted research into whether the disease can spread in other, less conventional ways.
The cases that have appeared lately do not all mimic classic mpox presentations, leading researchers to question whether infection can occur without direct contact. The WHO notes that “short‑range aerosols” might also play a role.
“It is premature to claim we understand all transmission pathways,” said Dr. W. Ian Lipkin, MD, professor of epidemiology and director of the Center for Infection and Immunity at Columbia University Mailman School of Public Health. “So far, most infections appear to arise from direct contact with an infected person.”
Understanding how mpox spreads will help shape guidance on measures such as personal protective equipment, improved ventilation, and isolation protocols.
The Centers for Disease Control and Prevention (CDC) identifies intimate skin contact—kissing, cuddling, sexual activity, or touching body parts with mpox lesions—as the primary route. Bodily fluids, lesions, and respiratory droplets from infected people or animals can transmit the virus.
Mildly different from COVID‑19, mpox can persist for extended periods outside the body, meaning contaminated objects (clothing, bedding, electronics, sex toys) can carry the virus. EPA‑approved household cleaners can neutralize it.
A study of four early European cases found mpox DNA in the semen of three patients, suggesting that exposure to infected semen could pose a risk, although mpox is not deemed a classic sexually transmitted infection.
“Semen exposure alone does not define transmission, but any contact with an infected person—whether skin‑to‑skin or via an object—still carries risk,” Lipkin noted.
Public settings such as trains or doctor’s offices represent low‑risk environments due to the small number of current cases. Nonetheless, limiting physical contact with strangers remains sensible.
Mpox was first identified in laboratory monkeys in 1958. The virus can be carried by various mammals, including rodents and non‑human primates. In the U.S., the first documented case in the 2003 outbreak arose from a prairie dog bite.
Although the exact reservoir species are unclear, rodents are the most likely candidates. The CDC advises caution around all animals and recommends good hygiene practices.
Humans may encounter the virus through animal bites or scratches, consumption or handling of wild game, or use of animal‑derived products. No confirmed cases of human‑to‑animal transmission exist, but avoiding contact with pets while sick could reduce spread.
In June, the CDC briefly suggested wearing masks, later removing that advice from its website to avoid confusion. However, infected individuals and close contacts are still urged to wear surgical masks.
While respiratory droplets can carry the virus, they “drop out of the air quickly” and are unlikely to cause infection. A Spanish study published in August suggests that skin‑to‑skin contact during sex remains the most probable transmission route.
Scientists are still determining whether asymptomatic transmission is possible. The WHO reports new cases in individuals with no known contact with sick persons, implying that some transmission chains may be undetected.
Questions persist about how long mpox has circulated undetected in regions outside Africa, why many cases outside Africa appear mild, and what role respiratory droplets, vaginal fluids, and semen play in spread.
“We still have much to learn, and our answers may evolve as the situation develops,” Lipkin concluded.
If you suspect you have been exposed to mpox or have questions about symptoms, speak with a health provider. In the interim, avoid close physical contact with others.