🤖 AI Summary
Constrained by technological, ethical, and privacy limitations, large-scale sexual contact networks remain largely unobservable, impeding understanding of the cross-regional transmission dynamics of sexually transmitted infections. This study leverages over 1.43 million client–sex worker reviews from The Erotic Review platform (1999–2024) to construct, for the first time, a multinational bipartite network. Applying complex network methodologies—including connected component identification, small-world analysis, and degree correlation—we uncover its macroscopic connectivity structure. The network exhibits small-world properties and contains a giant connected component. A small number of high-frequency cross-border clients act as spatial bridges, while long-term users serve as temporal bridges, both significantly enhancing network cohesion. Interactions involving transgender female sex workers are highly concentrated among these highly active cross-border clients, revealing pronounced structural centralization.
📝 Abstract
Sexual contact networks are fundamental to understanding the spread of sexually transmitted infections (STIs), yet their large-scale structure remains difficult to observe because of technical, ethical, and privacy constraints. Here, we analyze a large bipartite commercial-sex contact network comprising 1,436,738 client-sex worker links, constructed from reviews posted between 1999 and 2024 on The Erotic Review (TER), a review platform covering sex workers listed across 97 countries and territories. We examine the network's cross-country structure, focusing on how clients, sex workers, locations, and time periods are connected. The network formed a giant connected component containing most clients and sex workers and exhibited small-world-like properties, including short average path lengths, high bipartite clustering, and disassortative degree correlations. Although most reviews were associated with the United States, a small fraction of clients reviewed sex workers in multiple countries or territories, creating spatial bridges between otherwise distant regions. Long-term users created temporal bridges, making the aggregated network more compact than networks built from shorter time windows. Contacts involving transgender female sex workers were structurally concentrated: clients who reviewed both cisgender and transgender female sex workers represented a small minority but accounted for a large share of transgender-related reviews and showed higher cross-country activity. These findings show how a small number of highly connected clients with cross-country review activity can shape the large-scale connectivity of commercial-sex contact networks. More broadly, our results demonstrate the value and limitations of digital trace data for studying cross-country contact structures relevant to STI transmission.