Social network methodology for studying HIV epidemiology in men having sex with men.

A self-administered network-based questionnaire survey was conducted on 91 HIV-positive Chinese men having sex with men (MSM). Affiliation matrices were created to assess their networking pattern. The individuals' preferential use of venues for sex partnership before HIV infection has changed over three time periods of 1997-2000, 2001-2003 and 2004-2006.