Risk behaviors for HIV in sexual partnerships of San Francisco injection drug users

Abstract

While injection drug users (IDU) in the USA are known to form sexual partnerships with IDU as well as non-IDU, scientific research is lacking regarding risk behaviors for HIV transmission within these partnerships. Such information could aid HIV-prevention efforts among IDU and could also explain the relatively low prevalence of HIV among non-IDU heterosexuals in US cities such as San Francisco. Using data from a cross-sectional sample of San Francisco IDU we estimated (1) the prevalence of IDU-IDU and IDU-non-IDU sexual partnerships, (2) the frequency of serodiscordant unprotected intercourse in IDU-IDU and IDU-non-IDU sexual partnerships, and (3) the frequency of concurrence of sexual risk and injection-related risk within IDU-IDU sexual partnerships. An estimated 68% of sexually active San Francisco IDU is in IDU-IDU partnerships. Our analysis suggests that compared to IDU-non-IDU partnerships, IDU-IDU partnerships include a greater rate of episodes of serodiscordant unprotected intercourse (incidence rate ratio: 10.2; 95% confidence interval: 2.1-50.7). In fact, our data suggest that 92% of serodiscordant sexual episodes involving IDU are attributable to IDU-IDU pairings. Unprotected intercourse and needle sharing occur concurrently in an estimated 29% of IDU-IDU partnerships. Our data suggest that HIV-transmission risk is higher within IDU-IDU partnerships than it is within IDU-non-IDU partnerships. This disparity could explain the relatively low prevalence of HIV among non-IDU heterosexuals in San Francisco. We recommend that HIV-prevention efforts among IDU continue to address sexual risk behaviors for HIV transmission in addition to injection-related risk behaviors, with emphasis on IDU-IDU partnerships.

HIV Testing and HIV Positivity Among People Who Inject Drugs (PWIDs) With and Without History of High-Risk Behaviors: Findings From a Respondent-Driven Sampling (RDS) Survey in Southern Thailand

“…The prevalence of high-risk behaviors among our participants was lower than in previous studies. Shared needle use and history of risky sexual encounters were almost mutually exclusive (except for one person), this is vastly different from other studies which found these two behaviors to co-occur (Chen et al, 2014;Damas et al, 2021;Gangi et al, 2020). The history of shared needle use in our study was lower than in other respondentdriven sampling studies on behaviors of PWIDs (Chen et al, 2014;Korthuis et al, 2012).…”

“…Shared needle use and history of risky sexual encounters were almost mutually exclusive (except for one person), this is vastly different from other studies which found these two behaviors to co-occur (Chen et al, 2014;Damas et al, 2021;Gangi et al, 2020). The history of shared needle use in our study was lower than in other respondentdriven sampling studies on behaviors of PWIDs (Chen et al, 2014;Korthuis et al, 2012). Considering that there could be a gap between obtaining sterile syringe and actual use (Gangi et al, 2020;Korthuis et al, 2012), access to clean needles among PWIDs in our study could have been close to 100 percent.…”

“…Use of injection drugs may involve use of shared needles and syringes (Korthuis et al, 2012), which contributes to the 18% prevalence of HIV positivity among PWIDs worldwide (Degenhardt et al, 2017). In addition to use of shared needles, PWIDs may also engage in other behaviors with high risk of HIV transmission, including sex acts that involve mucosal tear (Billock et al, 2018; Duong et al, 2018), engaging in commercial sex work (Chen et al, 2014), and having sex without condom (Damas et al, 2021; Gangi et al, 2020).…”

Risk Factors for Acute and Early HIV Infection Among Men Who Have Sex With Men (MSM) in San Diego, 2008 to 2014

“…Although most previous HIV-risk models have focused on newly diagnosed chronic infection, 10 , 22 – 24 this represents one of the biggest studies to date to focus on incident HIV infection. 1 , 18 , 25 Although each of the 4 risk behaviors of our final model has been described previously to be associated with HIV infection individually (combination CRAI and 5 or more male partners, 18 , 26 , 27 CRAI with an HIV-positive male, 23 , 28 – 30 CRAI with a person who injects drugs, 28 , 31 , 32 and self-reported syphilis infection during the last 12 months), 33 , 34 these risk factors have not been described together in a multivariate model. By focusing only on AEH and investigating all of these factors together, we were able to generate a profile for AEH risk among MSM undergoing field-based screening, with an HR of 4.6 for AEH in individuals reporting at least 1 of the 4 risk behaviors.…”

Development and Validation of the San Diego Early Test Score to Predict Acute and Early HIV Infection Risk in Men Who Have Sex With Men

“…For the risk model, we selected 7 binary variables based on simplicity and published epidemiological data that supported inclusion in the predictive model. The variables selected were (1) ≥10 partners within the last year [5,18,19], (2) self-reported bacterial STI during the last 12 months (syphilis, gonorrhea, or chlamydia) [20,21], (3) the combination of condomless receptive anal intercourse (CRAI) and ≥5 male partners [22][23][24], (4) CRAI with an HIV-positive male [9,18,19], (5) CRAI with a person who injects drugs [9,25], (6) injection drug use with shared needles [22,26], and (7) noninjection stimulant drug use (NIDU, defined as use of methamphetamine, ketamine, cocaine, inhaled nitrites, Ecstasy, or GHB) [27,28].…”