Unprotected sexual contacts in HIV-positive persons constitute a great public health risk and can contribute significantly to the spread of HIV infection and AIDS. A Swiss study (Archives of Sexual Behavior 1998, 27(1) 577-90) investigated predictors of sexual risk behavior with regular and casual partners in 117 asymptomatic HIV-infected heterosexual and homosexual patients, who participated in the Swiss HIV Cohort Study (SHCS). Sexual risk behavior was defined as vaginal and/or anal sexual intercourse at least once without condom use during the six months prior to the interview. The data consisted of self-reports of sexual contacts and were supplemented by sociodemographic and interview information. The applicability of the data, especially to the US population, may be somewhat limited due to questions regarding the method of sample selection and data collection (e.g., the self-reports were not independently validated and no separate data were reported for males (73%) versus females (27%)). However, the major findings appear robust, are sufficiently alarming to warrant serious consideration, and have important educational, therapeutic, and forensic implications.

Among the 117 participants, 92% reported sexual contacts during the six months prior to the interview, and 26% had at least one unprotected vaginal and/or anal contact. When oral sex was included, unprotected sexual contact increased to 69%. Condoms were used at least once in 95% of heterosexual contacts and in 80% of homosexual contacts. Among the persons using condoms, 25% of the heterosexual and 10% of the homosexual participants reported breakage of the condom. Approximately 50% of the sample considered themselves "not so well" (25%) or 'poorly/very poorly" (25%) informed about AIDS. In the heterosexual group, 73% had sexual contact with HIV-negative regular partners (64%) or did not know their partner's HIV status (9%). For casual partners in the heterosexual group, 36% were either HIV- negative (18%) or of unknown status (18%). In the homosexual group, 41% of regular partners were either HIV-negative (25%) or of unknown status (16%), as were 53% of the casual partners (HIV-negative: 8%, and unknown status: 45%). During sexual contact, alcohol was used in 20% and recreational drugs in 25% of the instances.

The most alarming findings in this study are (1) the high prevalence of unprotected sex in HIV-positive patients, (2) the large number of partners with HIV-negative or unknown status, (3) the high rate of condom breakage, (4) the lack of adequate information about AIDS, and (4) the role of drug and alcohol in unsafe sex. The significant predictors of unsafe sex include frequency of sexual contacts with regular partners, consumption of alcohol in casual sexual contacts (a finding that contradicts findings from several recent studies), and low self-esteem which places persons at higher risk for unsafe sex. The authors suggest that a "silent agreement" exist between partners in which each is responsible for his/her own health and bears his/her own risk. They stress the importance of prevention programs, emphasizing knowledge of safe sex and the social responsibility of HIV-positive persons to inform their partners during sexual contacts. In my own practice, I routinely and explicitly inform HIV-positive persons about the moral and legal responsibilities of safe sex. Although the authors do not discuss the legal implications of unsafe sex, from a professional and forensic perspective it is imperative in the United States that we inform our HIV-positive patients/clients about such issues as criminal responsibility, civil liability, informed consent, and dangerousness of unsafe sexual behaviors.