Relative prevalence of different sexually transmitted infections in HIV-discordant sexual partnerships: data from a risk network study in a high-risk New York neighbourhood

Objectives: To determine infection patterns of sexually transmitted infections that facilitate HIV transmission among HIV-discordant couples. Methods: 112 initial respondents were recruited in an impoverished neighbourhood of Brooklyn, New York. Their sexual (and injection) partners were recruited in up to four additional network sampling waves for a final sample of 465 persons aged 18 years or older. After separate informed consent had been obtained, blood and urine were collected and tested for HIV, type-specific antibodies to herpes simplex virus (HSV-2), syphilis, chlamydia and gonorrhoea. Results: Of 30 HIV-discordant partnerships, five were same-sex male partnerships and 25 were opposite-sex partnerships. No subjects tested positive for syphilis or gonorrhoea. Two couples were chlamydia-discordant. For HSV-2, 16 couples were double-positive, eight discordant, four double-negative, and two comprised a HSV-2-negative with a partner with missing herpes data. Conclusions: HSV-2 was present in 83% of the HIV-discordant couples, chlamydia in 7%, and syphilis and gonorrhoea in none. HSV-2 is probably more important for HIV transmission than bacterial sexually transmitted diseases because it is more widespread. Even given the limited generalisability of this community-based sample, there seems to be an important HIV-prevention role for herpes detection and prevention activities in places where HIV-infected people are likely to be encountered, including sexually transmitted disease clinics, HIV counselling and testing programmes, prisons, needle exchanges, and drug abuse treatment programmes. The effects of HSV-suppressive therapy in highly impacted groups should also be investigated.