Molecular epidemiology, transmission and clinical features of 2022-mpox outbreak: A systematic review

The 2022-mpox outbreak has spread worldwide in a short time. Integrated knowledge of the epidemiology, clinical characteristics, and transmission of mpox are limited. This systematic review of peer-reviewed articles and gray literature was conducted to shed light on the epidemiology, clinical features, and transmission of 2022-mpox outbreak.

We identified 45 peer-reviewed manuscripts for data analysis. The standards of the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) Statement and Cochrane Collaboration were followed for conducting the study.

The case number of mpox has increased about 100 times worldwide. About 99% of the cases in 2022 outbreak was from non-endemic regions. Men (70%-98% cases) were mostly infected with homosexual and bisexual behavior (30%-60%). The ages of the infected people ranged between 30 and 40 years. The presence of HIV and sexually transmitted infections among 30%-60% of cases were reported. Human-to-human transmission via direct contact and different body fluids were involved in the majority of the cases (90%-100%). Lesions in genitals, perianal, and anogenital areas were more prevalent. Unusually, pharyngitis (15%-40%) and proctitis (20%-40%) were more common during 2022 outbreak than pre-2022 outbreaks. Brincidofovir is approved for the treatment of smallpox by FDA (USA). Two vaccines, including JYNNEOSTM and ACAM2000®, are approved and used for pre- and post-prophylaxis in cases. About 100% of the cases in non-endemic regions were associated with isolates of IIb clade with a divergence of 0.0018-0.0035. Isolates from B.1 lineage were the most predominant followed by B.1.2 and B.1.10.

This study will add integrated knowledge of the epidemiology, clinical features, and transmission of mpox.