The spread of monkeypox through small virus particles that linger in the air “has not been reported,” the US Centers for Disease Control and Prevention said in guidance posted Thursday. It may spread through “saliva or respiratory secretions” during face-to-face contact, but these secretions “drop out of the air quickly,” and studies have found that this method of transmission seems uncommon.
Unlike other viral diseases like Covid-19 and measles, the monkeypox virus isn’t subject to “airborne transmission,” which involves small particles that linger in the air or spread on air currents, the CDC notes. “In instances where people who have monkeypox have travelled on airplanes, no known cases of monkeypox occurred in people seated around them, even on long international flights.”
But because of the potential for monkeypox to spread through respiratory secretions, the agency “recommends that people infected with monkeypox wear a mask if they must be around others in their homes if close, face-to-face contact is likely.”
Masks are also recommended for health care workers and others who may be in close contact with an infected person.
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Previous CDC guidance had said that wearing a mask could help protect travelers from monkeypox, but that recommendation was removed late Monday because “it caused confusion,” the agency said.
The virus spreads primarily through direct contact with an infected person’s bodily fluids or sores, or with contaminated materials like linens, the guidance notes. Researchers are still learning about other potential transmission methods such as contact with an infected person’s semen or contact with an infected person who doesn’t have symptoms.
As of Thursday afternoon, the CDC reports 45 probable or confirmed cases of monkeypox in 15 states and the District of Columbia.
The CDC has reports of 1,356 confirmed cases in 31 countries where the virus is not endemic.