Large monkeypox study identifies new symptoms


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A study of more than 500 monkeypox cases in 16 countries identified some symptoms not recognized in current medical definitions, including single genital lesions and sores on the mouth or anus.

According to findings published in The New England Journal of Medicine98% of the patients with monkeypox were gay or bisexual men, 75% were white and 41% had HIV. Sexual activity was the suspected cause of 95% of the monkeypox infections.


Many of the cases reviewed in the study presented with symptoms not recognized in the current medical definitions of monkeypox, including single genital lesions and sores on the mouth or anus. Source: CDC.

“The current global outbreak of monkeypox virus infection in humans suggests changes in biologic aspects of the virus, changes in human behavior, or both,” John P. Thornhill, MD, PhD, locum consultant physician in sexual health and HIV and an honorary lecturer at Barts Health NHS Trust and Queen Mary University of London, and colleagues wrote.

“[S]uch changes,” they continued, “might be driven by waning smallpox immunity, relaxation of COVID-19 prevention measures, resumption of international travel, and sexual interactions associated with large gatherings.”

Thornhill and colleagues said monkeypox may have been “masquerading as other sexually transmitted infections” while it circulated undetected outside areas where it has historically been endemic.

“The current international case definitions may not be adequate to reflect the changing spectrum of clinical presentations, allow early identification, clarify transmission routes, and inform international public health policies and clinical trials,” they wrote.

To help better understand the clinical presentation of monkeypox in the ongoing global outbreak, Thornhill and colleagues formed an international collaboration to help create an international case series of PCR-confirmed monkeypox virus infections.

In total, the team identified and reported on 528 infections diagnosed between April 27 and June 24, 2022, at 43 sites in 16 countries, including the United States, Canada, Mexico, Argentina, Israel, Australia and 10 countries in Europe.

In addition to finding that most patients were gay or bisexual men and white, and that many had HIV, the researchers noted that 109 of 377 people tested had concurrent STIs.

According to the study, 95% of cases presented with a rash, with 64% of cases having less than 10 lesions, 73% having anogenital lesions and 41% having mucosal lesions, including 54 with only a single genital lesion. Other common symptoms preceding The rash included fever (62%), lethargy (41%), myalgia (31%) and headache (27%).

Additional data showed that 5% of all patients were treated with antivirals and 70 were hospitalized. The researcher explained that the reasons for hospitalization included pain management, soft tissue superinfection, pharyngitis limiting oral intake, eye lesions, acute kidney injury, myocarditis and infection control purposes.

“Because viruses know no borders, the world needs to move cohesively and quickly to close knowledge gaps and to contain the outbreak. Without widely available treatment or prophylaxis, rapid case identification is vital to containment,” the authors wrote. “As is common in clinical medicine, there is a diversity in how illnesses may manifest — and monkeypox is no different.”

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