ASSORTATIVE SEXUAL MIXING IN A HETEROSEXUAL CLINIC POPULATION - A LIMITING FACTOR IN HIV SPREAD

Objective: To assess the degree of sexual mixing in a sexually transmi tted disease clinic population stratified by country of birth. Design: Prospective linked HIV serosurvey incorporating demographic and sexua l risk data gathered by a doctor-administered questionnaire. Setting: The Department of Genitourinary Medicine at St Thomas' Hospital, Londo n, UK. Subjects: Fifteen thousand eight hundred and seventy-eight hete rosexuals who attended between April 1992 and February 1995. Main outc ome measure: The degree of assortative (like-with-like) mixing, after stratification of the population by country of birth, of index patient s, their parents and their sexual partners. Results: Sexual mixing in this population of sexually transmitted disease clinic attenders is hi ghly assortative when the CoB of parents (family origin) of index pati ents is taken into account. Conclusions: Our findings help to explain the low spread of heterosexual HIV infection in the UK to date, and ma y help future projections and health targeting of those at risk. This model can be applied to other mixed populations.