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Relationship of egocentric network characteristics and HIV transmission among MSM in Rio de Janeiro, Brazil

A.R.S. Périssé1, C.M.d. Amorim2, J.R.G.d. Silva2, M. Schechter2, W.A. Blattner1

Social Network (SN) research has become pivotal for a better understand of the STD/HIV epidemiology. Egocentric data measures the direct risk of acquisition of STDs. The index case’s (ego) perceptions of the risk of infection from an identified partner, is a reasonable surrogate for risk data directly collected from ego’s partners.

In June 2005 egocentric data collection at one of the HIV Voluntary Counseling and Testing (VCT) sites in Rio de Janeiro, Brazil, was implemented. An egocentric questionnaire was applied to a random sample of volunteers attending the VCT. Volunteers characterized partnerships as regular (stable relationship) or casual (sexual encounter with no intention of keeping a long-lasting relationship).

The 648 volunteers generated 1571 partners (median = 4). Overall HIV prevalence was 7.87% (51 out of 648). Prevalence among MSM and heterosexual ego was 27.7% and 3.8%, respectively. The odds of being HIV positive among ego men who have sex with men (MSM) was 8.8 times higher compared to heterosexuals (95%CI 4.4-17.5). In comparison to HIV positive heterosexual individuals, HIV positive MSM interacted with partners aged less than 25 years old (OR 1.6, 1.1-2.6), “mulato” (OR 1.8, 1.1-2.9), MSM (OR 6.0, 3.8-9.7), HIV positive (OR 3.4, 1.4-8.0), and were more likely to be unsure about the accuracy of their perception of partner risk (OR 2.1, 1.3-3.4). Stable versus casual relationship was not a risk factor for ego HIV seropositvity.

MSM HIV positive volunteers tended to interact with young “mulato” MSM partners (currently the most affected by the epidemic), who were HIV positive and appeared to know less about the risk of their partners than did heterosexuals, consistent with more frequent exposure to anonymous and thus high risk partners. The data are consistent with assortative mixing (like-like) among MSM and may help to explain high rates of infection in this population.

AIDS 2006 - XVI International AIDS Conference
Abstract no. CDC0071

Suggested Citation
"A.R.S.Périssé, et al. Relationship of egocentric network characteristics and HIV transmission among MSM in Rio de Janeiro, Brazil. : AIDS 2006 - XVI International AIDS Conference: Abstract no. CDC0071"