Most monkeypox cases in the current outbreak have been linked to sexual activity, but research published Wednesday by the US Centers for Disease Control and Prevention offers new insight into other ways it may be spreading.
A man noticed his first lesion and subsequently developed a rash about two weeks after attending a “large, crowded outdoor event at which he had close contact with others, including close dancing, for a few hours,” according to researchers from Stanford University School of Medicine. He tested positive for monkeypox after seeking care at an emergency department about a week later.
The patient’s “primary risk factor was close, nonsexual contact with numerous unknown persons at a crowded outdoor event,” the researchers wrote, and the case “highlights the potential for spread at such gatherings, which may have implications for epidemic control.”
The event he attended in the UK was not a rave and was not attended specifically or mostly by persons identifying as gay or bisexual, according to the researchers. While many attendees wore tank tops and shorts, he wore pants and a short-sleeve top. He did not notice anyone with skin lesions or who seemed ill, and he attended a few other similar events over the next four days.
According to CDC guidance, “monkeypox can spread to anyone” through close contact, which is often skin-to-skin, as well as intimate contact that includes sex, hugging, massage and kissing.
The patient – a man in his 20s who recently returned to the US after travel to the UK – did not report any sexual contact and did not have evidence of genital lesions. Samples of both saliva and nasal swabs tested positive for the virus, even though the patient did not report any related signs of illness such as fever, chills or cough.
An earlier analysis of monkeypox cases by the CDC found that early warning signs of illness are less common in the current outbreak compared with “typical” monkeypox. In about 2 in 5 cases, the illness started with the rash – but no reported prodromal symptoms such as chills, headache or malaise.
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These findings indicate that transmission may be “associated with clinical symptoms” and things like hotel bedding and high-touch areas in public settings may be modes of transmission.
However, despite no reported sexual contact, a rectal swab from the patient did test positive for the virus, which indicates “potential for sustained sexual transmission.”