post-exposure prophylaxis against HIV infection.

Sex frequency and sex planning among men who have sex with men in Bangkok, Thailand: implications for pre- and post-exposure prophylaxis against HIV infection.

Daily HIV anti-retroviral pre-exposure prophylaxis (PrEP) is being evaluated in clinical trials among men who have sex with men. However, daily PrEP may not be congruent with sexual exposure profiles of men who have sex with men. Here the authors investigate sex frequency and sex planning to identify and inform appropriate PrEP strategies for men who have sex with men. They evaluated sex frequency and sex planning in a cohort HIV-negative men who have sex with men in Bangkok, Thailand. Chi² test was used to compare reports of sex on different weekdays; logistic regression was used to identify predictors of sex frequency and sex planning. Of 823 men who have sex with men (mean age 28.3 yrs) 86% reported sex on 2 days per week or less and 65% reported their last sex to have been planned. Sex on the weekend (~30%) was more often reported than sex on weekdays (~23%). In multivariate analysis, use of alcohol, erectile dysfunction drugs, group sex, sex with a foreigner, buying and selling sex and a history of HIV testing were associated with having sex on 3 days per week or more; age 22 to 29 years, not identifying as homosexual, receptive anal intercourse and not engaging in group sex were associated with unplanned sex. Intermittently dosed PrEP (as opposed to daily) may be a feasible HIV prevention strategy and should be considered for evaluation in clinical trials. Predictors of sex frequency and sex planning may help to identify those in need for daily PrEP and those who may not be able to take a timely pre-exposure dose.

this study, planned sex meant ‘having made intentional arrangements to have sex, e.g. you went to the park, sauna, bar, or online to find a sex partners or you had made an appointment with another man to have sex’. Two-thirds of the men in this study had planned sex on the first encounter of the last day they had sex. Given the sex frequency reported in this study, it would be possible for many men who have sex with men in Bangkok to use intermittent pre-exposure prophylaxis (PrEP), if it proved to be effective. For others who are having sex more frequently or who are less able to plan when they will have sex, a daily antiretroviral dose would be more practical. There is a daily dose effectiveness trial underway among men who have sex with men in Peru, Ecuador, USA, South Africa, and Thailand - it will report results in the next 6 months. A safety and acceptability study of intermittent PrEP among men who have sex with men is underway in Kenya and Uganda and two further safety studies are planned. If daily PrEP provides protection and intermittent PrEP is safe, the question will be whether intermittent PrEP will be effective and for which men. Local studies such as this one eventually can inform the counselling that will help men to choose a tailored approach that will work best for them.