Men who have sex with men (MSM) who have overlapping sexual partnerships are more likely to be recently infected with HIV and to be a part of a cluster of infections circulating between men in a community, aidsmap reports.
Researchers have argued that this finding suggests that having such partnerships could be an indicator that individuals are good candidates for Truvada (tenofovir/emtricitabine) as pre-exposure prophylaxis (PrEP).
Publishing their findings in the journal AIDS, investigators conducted genetic analyses on HIV drawn from 984 newly infected MSM participating in two studies in San Diego. The men were not on HIV treatment. A total of 288 of these men completed a computer interview about their sexual partnerships during the previous three months.
The researchers defined overlapping, or concurrent, partnerships as having sex multiple times with at least two men during the same period.
Out of the 984 men, 594 had contracted HIV during the previous six months. A total of 452 men (45 percent) were presumed to be a part of a pair or group of genetically linked transmissions.
The investigators found that 61 percent of the genetically linked transmissions were between just two people. The remaining 39 percent were linked within transmission clusters. The largest cluster included 21 people, meaning that HIV had circulated relatively quickly within this sizeable sexual network.
Out of the 288 study participants who provided information about the last two or three sexual partners they had during the previous three months, 75 percent reported having condomless intercourse with at least one partner. Fifty-four percent said they engaged in overlapping sexual partnerships during this time. Thirty-seven percent said they had more than one “main” partnership.
Sixty-seven percent of the men who said they had overlapping partnerships had HIV that was genetically linked to at least one other member of the study, compared with 46 percent of those who did not report such partnerships. The virus of those reporting overlapping partnerships was genetically linked to an average of 2.5 other men’s HIV, compared with an average of 1.6 among those not reporting overlapping partnerships.
After adjusting the data for various factors, the researchers found that compared with not reporting such partnerships, reporting overlapping partnerships was associated with a 69 percent increased risk of being a part of a transmission cluster and 40 percent higher number of genetically linked viral connections.
Thirty-two percent of those with overlapping partnerships were apparently the source of a genetically linked HIV infection, a rate 58 percent higher than seen among those without such partners.
To read the aidsmap article, click here.
To read the study abstract, click here.