Background: Sexual networks play an important role in the transmission of sexually transmitted infections (STIs) and HIV. However, because of the challenges of collecting network data, relatively few empirical reports exist about the structure of sexual networks in general population samples. This study describes the structure of the sexual networks of a household sample of urban black adolescents living in an area with moderate endemic STI rates.
Methods: Random digit dialing was used to recruit a household sample of black adolescents from the Bayview-Hunter's Point neighborhood of San Francisco. Participants' recent partners and partners of partners were recruited through snowball sampling. Biologic samples were tested for current infection with gonorrhea or chlamydia. Social network analysis methods were used to describe the characteristics of the resulting sexual networks.
Results: One hundred and sixty-six sexually active participants were connected to 388 network members in 159 separate sexual network components. Despite relatively high prevalence of bacterial STIs (13%), components were small (3.5 people on average, and half involved only 2 people), linear and acyclic. Females were less central in their networks than males by local measures but just as central when overall structure was taken into account.
Conclusions: Our results confirm, in a new setting, previous observations that sexual network structures necessary for endemic transmission of gonorrhea and chlamydia are sparsely connected.