Sexual networks and sexually transmitted infections: innovations and findings.

PURPOSE OF REVIEW: With increasing recognition of the importance of sexual networks in the dissemination of sexually transmitted infections (STIs), research is expanding. This review focuses on methodology for conducting sexual network research with in-depth presentations of recent and novel studies conducted on four continents.

RECENT FINDINGS: Studies in diverse settings such as rural villages of China and St. Petersburg, Russia offer compelling evidence that HIV is no longer confined to needle-sharing and drug-using networks, but has diffused into the general population via heterosexual transmission. Because the networks are not especially densely connected, the shift will happen slowly. In contrast, studies conducted on both the east and west coasts of the US among men who have sex with men and women show that, despite high HIV prevalence, substance abuse, homelessness, and unprotected anal intercourse, the size of the population and sexual network dynamics are insufficient to cause widespread heterosexual HIV transmission. In Africa, holding low-risk positions in sexual networks can elevate the risk of infection, whereas higher-risk partnerships also simultaneously affect HIV transmission.

SUMMARY: The diversity of findings in a diversity of settings demonstrates that not all networks operate in similar ways.