Mpox and sexually transmitted infections: syndemic drivers of transmission and disease outcomes-A Narrative Review.

The worldwide outbreak of mpox (formerly monkeypox) in 2022 emerged as a public health emergency posing greater threat to persons with sexually transmitted infections (STIs). This outbreak featured an increase in overlap between mpox and STIs reflecting evolving transmission dynamics in sexual networks. Epidemiological data reveal that STIs such as human immunodeficiency virus (HIV), Chlamydia trachomatis, herpes simplex virus, syphilis have been frequently associated with mpox infection highlighting the role of sexual contact in its transmission. A narrative review was conducted using PubMed and Google Scholar to identify relevant literature published between 2008 and 2026, focusing on mpox, STIs, co-infections, and pregnancy outcomes. Evidence suggests that biological, behavioural and structural factors may interact to influence mpox transmission and clinical outcomes. STI co-infection may be associated with mucosal invasion and immune modulation plausibly affecting disease progression, however direct mechanistic evidence remains limited. Although mpox infection has majorly affected gay, bisexual and other men who have sex with men (GBMSM), its severity in women particularly during pregnancy raises concerns regarding vertical transmission and maternal and neonatal complications. This review highlights current evidence on mpox-STI co-infections, and applies a syndemic framework to interpret their co-occurrence within biological, behavioural and structural contexts. While this perspective provides understanding regarding transmission patterns, further research is needed to establish the extent of these interactions. Recognizing these factors is important for screening, early diagnosis and management strategies to mitigate future outbreaks and impact of mpox. Summary: This narrative review on mpox and STI co-infections explores syndemic interactions, transmission dynamics and implications for disease outcomes and public health management.