SOCIOMETRIC RISK NETWORKS AND RISK FOR HIV-INFECTION

Objectives. This study examined whether networks of drug-injecting and sexual relationships among drug injectors are associated with individ ual human immunodeficiency virus (HIV) serostatus and with behavioral likelihood of future infection. Methods. A cross-sectional survey of 7 67 drug injectors in New York City was performed with chain-referral a nd linking procedures to measure large-scale (sociometric) risk networ ks. Graph-theoretic algebraic techniques were used to detect 92 connec ted components (drug injectors linked to each other directly or throug h others) and a 105-member 2-core within a large connected component o f 230 members. Results. Drug injectors in the 2-core of the large comp onent were more likely than others to be infected with HN. Seronegativ e 2-core members engaged in a wide range of high-risk behaviors, inclu ding engaging in risk behaviors with infected drug injectors. Conclusi ons. Sociometric risk networks seem to be pathways along which HIV tra vels in drug-injecting peer groups. The cores of large components can be centers of highrisk behaviors and can become pockets of HIV infecti on. Preventing HIV from reaching the cores of large components may be crucial in pre venting widespread MV epidemics.