Clinical Characteristics of Human Mpox (Monkeypox) in 2022: A Systematic Review and Meta-Analysis

Since May 2022, large numbers of human mpox (previously known as monkeypox) cases have been reported in non-endemic regions. We conducted a systematic review and meta-analysis to elucidate clinical characteristics of the current mpox outbreak. Our systematic review and meta-analysis were undertaken according to PRISMA and MOOSE guidelines. We searched PubMed, EMBASE, and Web of Science for publications between 1 January and 11 November 2022. Random-effects models were used to pool results. Heterogeneity was assessed using I². This study is registered with PROSPERO, CRD42022355590. Skin lesions (95.2%, 95% CI [93.3-96.9%]), fever (58.4%, [54.9-61.8%]) and lymphadenopathy (53.0%, [48.7-57.3%]) were the most common symptoms. The most common dermatological manifestations were anogenital lesions (65.7%, [57.8-73.0%]), and the most common lymphadenopathy was inguinal (46.8%, [40.6-53.0%]). There were no differences in symptoms including malaise, fever, headache, and genital, anal, and oropharyngeal lesions according to HIV infection status. Median age of patients varied from 15 to 57.5 years (median, 35 years). The median proportion of men who had sex with men (MSM) was 100.0% (20.6-100.0%). The median proportion of patients who reported recent sexual exposure was 99.2% (14.3-100.0%). The median proportion of PLHIV was 42.2% (0.0-100.0%). Skin lesions, fever, inguinal lymphadenopathy, and anogenital lesions were the most common symptoms of mpox reported in the current outbreak. Existing guidelines should be updated to reflect these clinical manifestations and groups at highest risk of infection, MSM in particular.