Characteristics of mpox virus infections across 16 countries

1. Patients with mpox infections presented with a variety of dermatologic and systemic symptoms.

2. Mpox virus infections were previously endemic to African regions but have now occurred in outbreaks worldwide.

Evidence Rating Level: 2 (Good)

Study Rundown: Mpox is a zoonotic orthopox DNA virus that was previously reported in isolated outbreaks across Africa. Mpox is related to smallpox and typically occurs after interaction with affected rodents. It has historically had limited secondary spread in humans and has therefore previously not been well-researched. In 2022, outbreaks have occurred in several non-endemic regions globally. There is a knowledge gap as to the virus characteristics, including transmissibility as well as disease course in humans. The present study involved the development of a large-scale global mpox case series to describe the demographics, clinical presentation, and outcomes of those infected. A large proportion of patients were also living with HIV infections. Additionally, gay and bisexual White men were disproportionately affected. Skin lesions were commonly found in the anogenital area. A wide spectrum of skin lesions were observed. The transmission was predominantly through sexual contact. This study effectively described the prevalence, presentation, and complications of the mpox virus worldwide. Although, the study was limited in that a convenience sample was collected without continued monitoring of viral shedding after lesion resolution.

Click to read the study in NEJM

Relevant Reading: Tecovirimat and the Treatment of Monkeypox — Past, Present, and Future Considerations

In-Depth [case series]: The present case series study examined mpox in the global context, with cases included from 16 countries. A total of 528 patients were included with confirmed human mpox infections. Information collected for each case included patient sociodemographic characteristics, exposure history, signs and symptoms, disease complications, and clinical course. Of those who were infected, 98% identified as gay or bisexual men and 75% were White. Skin lesions were identified on 95% of those infected and a spectrum of skin presentations was described. These included macular, pustular, vesicular, and crusted lesions. Most patients presented initially with skin lesions in the anogenital area, body, or face (95%). Systemic features were also reported, such as fever (62%), lethargy (41%), myalgia (31%), and headache (27%). The median time between the onset of symptoms to a positive polymerase chain reaction (PCR) result was five days but ranged from two to 20 days. The most common mode of transmission was close sexual contact, which was reported in 95% of cases. The most common reason for hospitalization was pain management and overlying soft-tissue superinfection. Two forms of severe complications were observed: one case of epiglottitis and two cases of myocarditis. The most common site sampled for PCR testing was skin or anogenital lesions (97%). In summary, continued data collection of mpox virus cases will aid in the development of prevention and intervention strategies.

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