Genetic Network Analysis to Assess the Risk of Human Immunodeficiency Virus Transmission Among Men Who Have Sex With Men Seeking Partners on the Internet

Abstract

Background: Online partner seeking (OPS) among men who have sex with men (MSM) is associated with increased risk behavior including frequency of unprotected anal intercourse, number of partners, and incidence of sexually transmitted infections (STIs). However, the impact on transmission of human immunodeficiency virus (HIV) is uncertain.

Methods: MSM diagnosed with acute and early HIV infection were recruited from the Primary Infection Resource Consortium. HIV transmission events in the year following infection were inferred using estimated date of infection combined with genetic network analysis with linked sequences defined as ≤0.015 sequences/site difference in the HIV type 1 (HIV-1) pol coding region. Participants completed a detailed baseline questionnaire including reported methods of meeting sexual partners, including OPS, in the prior 3 months, and regression was performed with inferred transmission as the outcome.

Results: From 147 MSM who completed the questionnaire, there were an associated 20 inferred HIV transmissions. No association with OPS was found (odds ratio, 0.64 [95% confidence interval, .24-1.69]; P = .37), though individuals who reported OPS were more likely to have reported a greater number of partners (P = .003) and prior STIs (P = .002). Geospatial analysis did not indicate that OPS was associated with increased geographical reach of the user (P = .68).

Conclusions: Individuals reporting OPS did not have increased odds of inferred HIV-1 transmission in the year following infection using genetic linkage analysis despite apparently increased risk behavior. OPS also did not increase the geographic distance between genetically clustered HIV infections, suggesting that individuals mainly use the internet to meet partners in their local region.

Keywords: HIV; MSM; internet; online partner seeking; transmission network.

Figure 1.

Transmission network from Primary Infection Resource Consortium (PIRC), with linkages shown between nodes (individuals) with viral genotypes ≤0.015 substitutions/site [21]. Use of the internet to meet sexual partners is shown by dark green, and those who did not use the internet to meet sexual partners are shown in light green. Gray nodes represent individuals who are part of the PIRC who were recruited prior to the introduction of the venue questionnaire, had an estimated date of infection >90 days prior, or who did not complete the venue questionnaire during the study period.

Figure 2.

Mean geographical distance with 95% confidence intervals between individuals who have genetically related human immunodeficiency virus infection (≤0.015 substitutions/site) and individuals using online partner seeking (OPS) (A) or those who reported no OPS (B). P values refer to the difference in mean geographical distance of clustered individuals (orange/yellow bars) compared to the average distance between random selection of sequences (blue bars). Abbreviation: CI, confidence interval.

Figure 3.

A, Number of study participants by zip code in San Diego County, California. B, Proportion of participants (by zip code) who were found to be part of a genetic cluster. The number of individuals who were part of a genetic cluster is shown by a red dot (reported online partner seeking [OPS]) or green dot (no reported OPS). Size of dot is representative of the number of individuals.