Mpox spreads mainly through close physical contact with an infected person. That includes skin-to-skin touch, kissing, sex, and even prolonged face-to-face interaction close enough to exchange respiratory particles. The virus can also survive on contaminated objects like bedding and clothing, though direct contact remains the dominant route.
Close Contact Is the Primary Route
The mpox virus transmits through several forms of close contact. Skin-to-skin touch, including sexual contact, is the most efficient way the virus moves between people. Kissing and other mouth-to-skin contact also transmit it. Even being face-to-face with someone who has mpox, close enough to talk or breathe on each other, can generate infectious respiratory particles that carry the virus.
This is not a virus that spreads easily across a room or through brief, casual encounters. It requires sustained, close proximity. Household members of an infected person are at elevated risk precisely because of the daily intimacy of shared living spaces: shared bathrooms, shared furniture, prolonged time spent near each other.
Sexual Contact Carries the Highest Risk
Since the global outbreak that began in 2022, sexual contact has been the dominant transmission route. A CDC study of men who have sex with men found that condomless receptive anal sex with an infected person carried 5.4 times the odds of infection compared to other forms of close contact without that specific exposure. The virus reaches mucosal surfaces efficiently during sex, which helps explain the elevated risk.
Condoms reduce exposure at genital and anal sites, but they don’t eliminate risk entirely. Mpox lesions can appear anywhere on the body, and the virus is also present in saliva and respiratory secretions. Someone with lesions on their hands, torso, or face can transmit the virus through skin contact during intimacy regardless of condom use.
In the ongoing clade II outbreak (the strain circulating globally since 2022), transmission has been almost exclusively linked to sexual contact. The clade I outbreak originating in Central Africa shows a broader pattern: sexual contact, day-to-day household contact, and healthcare settings have all played roles. Both clades spread, and are treated and prevented, in similar ways.
Contaminated Surfaces and Objects
The mpox virus is unusually durable for an enveloped virus. Virus particles get embedded in the fibrous material of scabs and crusts shed from lesions, which protects them from drying out. In one household study, viable virus was detected on surfaces at least 15 days after the infected person had been there.
Porous materials pose a greater risk than hard surfaces. Researchers found viable virus on 60% of porous surfaces tested (bedding, clothing) compared to just 5% of nonporous surfaces (metal, plastic). That said, the amount of virus recovered was low, suggesting indirect transmission through contaminated objects is possible but less likely than direct skin contact. Shared bed linens, towels, and clothing worn against an active rash are the most plausible culprits. Needle injuries in healthcare settings and tattoo parlors are another documented route.
When Someone Is Contagious
The infectious window has clear boundaries. During the incubation period, which typically lasts 1 to 2 weeks after exposure, a person is not contagious. Once early symptoms appear (fever, body aches, swollen lymph nodes), they may become contagious even before the characteristic rash develops. A person remains contagious until every lesion has scabbed over and every scab has fallen off, revealing fresh, intact skin underneath. Only then is the infection no longer transmissible.
There is also growing evidence that some people carry and potentially spread the virus without ever showing symptoms. A study of men who have sex with men in Japan found that asymptomatic infections were comparable in number to symptomatic ones, and some asymptomatic individuals had viral loads high enough to suggest potential infectiousness. The exact role of asymptomatic spread in driving outbreaks is still unclear, but it likely contributes to cases that seem to appear without a known exposure.
Transmission During Pregnancy
The virus can pass from a pregnant person to their baby during pregnancy or birth. A large prospective study published in The Lancet tracked 88 pregnant women with clade I mpox in the Democratic Republic of Congo. The findings were stark: 45% of pregnancies with known outcomes ended in fetal loss, including miscarriages and stillbirths. Of 38 live births, four newborns had lesions consistent with congenital mpox infection.
Infection during the first trimester carried the highest risk. Women infected in the first trimester had significantly worse outcomes than those infected in the second or third trimester. High viral loads, the presence of genital lesions, and co-infection with HIV all independently increased the risk of adverse outcomes.
Animal-to-Human Transmission
Mpox is a zoonotic virus, meaning it originally jumped from animals to humans. In parts of Central and West Africa, people can contract the virus through direct contact with infected animals, including bites, scratches, or handling bushmeat. Rodents are considered the likely animal reservoir, though the precise species maintaining the virus in nature have not been definitively identified. In non-endemic countries, the vast majority of cases result from human-to-human transmission rather than animal contact.
Reducing Spread at Home
If someone in your household has mpox, practical steps can significantly lower the risk to others. The infected person should isolate in a separate room and, if possible, use a separate bathroom. Do not share bed linens, towels, clothing, drinking glasses, or eating utensils. The person with mpox should handle their own bandage changes while wearing disposable gloves and wash hands immediately after removing them. Any clothing that touches the rash should be laundered right away.
Upholstered furniture and mattresses are harder to decontaminate, so covering them with waterproof sheets, blankets, or tarps prevents the virus from settling into fabrics you can’t easily wash. Commonly touched surfaces like light switches, counters, faucets, and toilet seats should be cleaned regularly with an EPA-registered disinfectant. Contaminated waste, including used bandages and gloves, should be bagged and disposed of promptly.