Summary Rectal gonorrhea and chlamydia increase the risk of a new diagnosis of HIV independent of rectal sexual behavior among men who have sex with men. Background Rectal sexually transmitted infections (STI) have been associated with HIV diagnosis, but inferring a causal association requires disentangling them from receptive anal intercourse (RAI). Methods We conducted a stratified case-control study by frequency matching 4 controls to each case within year using clinical data from men who have sex with men (MSM) attending the Seattle STD Clinic 2001–2014. Cases were MSM with a new HIV diagnosis and negative HIV test ≤12 months. Controls were HIV-negative MSM. All included men had rectal STI testing, tested negative for syphilis, and had complete sexual behavior data. We categorized men by RAI: (1) none; (2) condoms for all RAI; (3) condomless RAI (CRAI) only with HIV-negative partners; and (4) CRAI with HIV-positive or unknown-status partners. We created three logistic regression models: (1) three univariate models of concurrent rectal gonorrhea, rectal chlamydia, and rectal STI in ≤12 months with new HIV diagnosis; (2) those three infections, plus age, race, year, number of sexual partners ≤2 months, and methamphetamine use; and (3) model 2 with RAI categories. We calculated the population attributable risk of rectal STI on HIV diagnoses. Results Among 176 cases and 704 controls, rectal gonorrhea, chlamydia and rectal STI ≤12 months were associated with HIV diagnosis. The magnitude of these associations attenuated in the second model, but persisted in model 3 (gonorrhea aOR 2.3 95%CI 1.3 – 3.8; chlamydia aOR 2.5 95%CI 1.5 – 4.3; prior STI aOR 3.0 95%CI 1.5 – 6.2). One in 7 HIV diagnoses can be attributed to rectal STI. Conclusion Rectal STI are independently associated with HIV acquisition. These findings support the hypothesis that rectal STI play a biologically-mediated causal role in HIV acquisition and support screening/treatment of STI for HIV prevention.

Enrolling large numbers of high-risk men who have sex with men (MSM) into human immunodeficiency virus (HIV) prevention studies is necessary for research with an HIV outcome, but the resources required for in-person recruitment can be prohibitive. New methods with which to efficiently recruit large samples of MSM are needed. At a sexually transmitted disease clinic in Seattle, Washington, in 2013-2014, we used an existing clinical computer-assisted self-interview that collects patients' medical and sexual history data to recruit, screen, and enroll MSM into an HIV behavioral risk study and compared enrollees with men who declined to enroll. After completing the clinical computer-assisted self-interview, men aged ≥18 years who reported having had sex with men in the prior year were presented with an electronic study description and consent statement. We enrolled men at 2,661 (54%) of 4,944 visits, including 1,748 unique individuals. Enrolled men were younger (mean age = 34 years vs. 37 years; P < 0.001) and reported more male sex partners (11 vs. 8; P < 0.001) and more methamphetamine use (15% vs. 8%; P < 0.001) than men who declined to enroll, but the HIV test positivity of the two groups was similar (1.9% vs. 2.0%; P = 0.80). Adapting an existing computerized clinic intake system, we recruited a large sample of MSM who may be an ideal population for an HIV prevention study.

Background Little is known about the frequency of ongoing HIV transmission within U.S. African immigrant communities. Methodology We used HIV surveillance and partner services data to describe African-born persons newly reported with HIV infection in King County (KC), WA from 1/1/2010–12/31/2013. We performed phylogenetic clustering analysis of HIV-1 pol to identify putative transmission events within this population. Results From 2010–2013, 1,148 KC adults were reported with HIV, including 102 (9%) born in Africa. Forty-one African-born cases were interviewed and reported diagnosis after arrival in the U.S. Fourteen (34%) reported ≥1 negative test prior to diagnosis, and 9 (26%) reported ≥1 negative test after U.S. arrival. Pol genotypes were available for 7 of these 9. For 2 of these 7, a KC case was the nearest phylogenetic neighbor; 2 others were infected with subtype B virus. Discussion We found substantial evidence of ongoing HIV transmission in the African community of KC.