AIDS 2014A cohort of young gay men in Bangkok, Thailand, is acquiring HIV at a rate of 9 percent a year among those not using condoms consistently and 2 percent a year among those who report 100 percent condom use, aidsmap reports. Researchers analyzed data on 494 young men who have sex with men (MSM) who were between the ages of 18 and 24 upon their 2006 to 2010 enrollment into the Bangkok MSM Cohort Study. Results were presented at the 20th International AIDS Conference (AIDS 2014) in Melbourne.

During three to five years of follow-up of these men, who return three times a year for HIV testing and behavioral questionnaires, 118 have contracted HIV, or 23.8 percent. Those who reported having anal sex without a condom had a 46 percent likelihood of becoming HIV positive, although those who had condomless intercourse and were only the insertive partner (the top) had just a 14 percent likelihood of acquiring the virus.

The study found that 100 percent condom usage was linked to a 54 percent reduced risk of getting HIV. However, self-reports about condom use are notoriously unreliable. If a significant proportion of the men who said they were using condoms all the time actually used them at a diminished rate, then the efficacy of consistent condom use is being underestimated in the case of these men.

Meanwhile, refraining from receptive anal intercourse (being the bottom) reduced the risk of HIV by 70 percent.

The following behaviors or circumstances were associated with varying degrees of increase in the likelihood of contracting HIV: having condomless anal intercourse, 2.8 fold; being paid for sex, 2.2 fold; having casual sex at a sauna, 1.9 fold; having casual sex at home, 1.6 fold; living alone or with a roommate, as opposed to with family, 1.5 fold.

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