Abstract
Background:
HIV pre-exposure prophylaxis (PrEP) is safe and effective for use in people who inject drugs (PWID), but PrEP is underutilized in this population. We assessed awareness of PrEP and correlates of interest in PrEP among PWID in Seattle, Washington.
Methods:
This study analyzed data from a 2019 survey of PWID at 3 Seattle-area syringe service programs (SSPs). We used descriptive statistics to compare PrEP-aware and unaware PWID and multivariable Poisson regression with robust standard errors to estimate adjusted prevalence ratios (APR) for interest in PrEP.
Results:
Among 348 HIV-negative PWID, ≤1% were currently taking PrEP, 51% were PrEP aware and 46% were interested in PrEP. Interest in PrEP was inversely associated with prior PrEP awareness (APR 0.58, 95% CI 0.45 – 0.74); however, interest in PrEP was high among PWID meeting pre-specified risk criteria for HIV (APR 1.41, 95% CI 1.06 – 1.88).
Conclusions:
Our results suggest increasing awareness of PrEP may not be sufficient to promote PrEP uptake among PWID, and further efforts are needed to understand perceptions of risk for HIV, determinants of PrEP use, and to investigate successful strategies for PrEP implementation and delivery in this marginalized population.
Keywords: Pre-exposure prophylaxis, people who inject drugs, HIV prevention, syringe service programs
Introduction
People who inject drugs (PWID) are disproportionately affected by the HIV epidemic, and in the past decade, there has been an increase in HIV outbreaks among PWID both in the United States (U.S.) and abroad. (Des Jarlais et al., 2018; Des Jarlais et al., 2020; Golden et al., 2019; Peters et al., 2016) HIV pre-exposure prophylaxis (PrEP) has been deemed safe and effective for use in PWID, and in 2013 the Centers for Disease Control and Prevention (CDC) released guidelines outlining its use in PWID. (Centers for Disease Control and Prevention, 2018; Choopanya et al., 2013) Despite this, PrEP remains underutilized among PWID, (Roth et al., 2019) with qualitative studies citing several individual, social, and structural barriers to its use. (Allen et al., 2020; Bazzi et al., 2018; Biello et al., 2018; Footer et al., 2019) Similarly, awareness of PrEP is low among PWID, and studies show that only 12 – 31% of PWID are PrEP-aware. (Kuo et al., 2016; Roth et al., 2019; Sherman et al., 2019; Walters et al., 2017; Walters et al., 2017) Nevertheless, studies also show that when made aware of PrEP, 47 – 79% of PWID report interest in or willingness to use PrEP, with younger age, female gender, and high-risk injection behaviors being positively associated with interest in PrEP. (Kuo et al., 2016; Roth et al., 2018; Sherman et al., 2019)
In Seattle and King County, Washington, the prevalence of HIV has historically been low among PWID, particularly among women and men who have sex with women, among whom HIV prevalence is estimated to be 1 – 3%. (Golden et al., 2019) However, a recent cluster of linked HIV cases among heterosexual men and women living homeless in North Seattle, most of whom inject drugs, exposed the vulnerability of this population to HIV infection. (Golden et al., 2019) While factors driving the emergence of this cluster are complex, a lack of syringe and clinical services for PWID in North Seattle, the ongoing opioid epidemic, exchange sex, and a lack of affordable housing were all likely contributing factors. (Golden et al., 2019) In the wake of Seattle’s recent HIV cluster, and other similar outbreaks of HIV among PWID in the United States, this study aims to assess awareness of PrEP and investigate correlates of interest in PrEP among PWID at Public Health – Seattle & King County (PHSKC) syringe service programs (SSPs). (Peters et al., 2016)
Materials and methods
Study sample
This study analyzed data from a 2019 survey administered by PHSKC to clients at three Seattle area SSPs. This serial cross-sectional surveillance survey is conducted biennially and collects information on client demographics, health conditions, drug use, sexual behavior, and healthcare needs. In an attempt to survey all SSP clients during a two-week window, the survey team used a census sampling approach. All SSP clients who sought services at one of the three PHSKC SSPs during the data collection period were asked by SSP staff and volunteers to participate after receipt of services. Clients were only eligible to complete the survey once, and SSP clients who did not wish to participate were allowed to voluntarily decline. Additional details on survey methodology have been previously published. (Burt et al., 2017; Glick et al., 2018; Jenkins et al., 2011; Peavy et al., 2012)
For the purposes of this study, the analytic sample was restricted to persons who reported injecting drugs in the past three months and who reported being HIV negative. Participants who did not know their HIV status, or those who self-reported being HIV positive were excluded.
Data collection
Data collection occurred over a two-week period, from July 8 to July 20, 2019. After providing informed consent, participants were given an interviewer-administered survey. Interviews were conducted by SSP staff and by interviewers from other surveys of PWID, all of whom had extensive experience working with PWID and populations at risk for HIV. Surveys were primarily conducted on tablets, although paper-based surveys were used for some participants recruited at mobile sites. All data were entered into REDCap (Research Electronic Data Capture). (Harris et al., 2019; Harris et al., 2009) No personal identifying information was collected, aside from zip code. In most instances, clients completed the survey in approximately 10–15 minutes. No compensation was provided for survey participants.
The survey was conducted by PHSKC for the purposes of public health surveillance and was therefore not considered to be human subjects research. The University of Washington Human Subjects Division reviewed proposed analyses for this study and determined it did not involve human subjects and therefore did not require IRB approval.
Measures
The primary outcomes of interest were prior awareness of PrEP and interest in PrEP. Awareness of PrEP was defined by answering “yes” to “Have you ever heard of HIV pre-exposure prophylaxis or PrEP?” Interest in PrEP was defined by answering “very” or “somewhat” to the question: “PrEP is a pill you can take to prevent you from getting HIV. How interested are you in being on PrEP?” Although current use of PrEP was not an exclusion criterion for this study, due to survey skip patterns, interest in PrEP was only assessed among those who were not currently taking PrEP. Potential correlates of interest in PrEP were identified a priori and included: age, gender, race, housing status, engaging in exchange sex, being a man who has sex with men (MSM), drugs used in the past 3 months, number of days injected in the last 7 days, sharing syringes in the past 3 months, sharing injection equipment in the past 3 months, reporting a sexually transmitted infection (STI) in the past 12 months, having participated in treatment for substance use disorder in the past 12 months, health insurance status, and being at “high-risk” for HIV infection, as described below.
Characteristics of people newly diagnosed with HIV during the 2018 cluster of linked HIV infections in Seattle were evaluated to assess factors that may place PWID at increased risk for HIV. (Golden et al., 2019) Based on characteristics of this cluster, a composite “high-risk” exposure variable was created, reflecting survey participants who self-reported living homeless in addition to using methamphetamine and heroin. Although many persons newly diagnosed with HIV during the 2018 cluster of linked HIV infections also reported exchanging sex for money or drugs, due to low numbers of persons reporting exchange sex in the survey, exchange sex was not included in the “high-risk” variable, as to not have this composite variable serve as a proxy for exchange sex or for gender. For the purposes of this composite variable, homelessness was defined as being “homeless” or having “temporary/unstable” housing. Methamphetamine and heroin use was defined as any use of both drugs, either separately or together (goofball), and not restricted to intravenous use.
Statistical analysis
Chi-squared and Fisher exact tests were used to compare proportions between PrEP aware and unaware groups. A Wilcoxon rank sum test with continuity correction was used to compare continuous variables.
We used bivariate Poisson regression with a log link and robust standard errors to calculate the prevalence ratio (PR) of being interested in PrEP among HIV-negative PWID who were not currently on PrEP. We chose Poisson regression, over logistic regression, given the high prevalence of the outcome. Variables with a statistically significant association with interest in PrEP, defined as an alpha of ≤0.05, were then included in a multivariable model. Multivariable Poisson regression with a log link and robust standard errors was subsequently used to estimate adjusted prevalence ratios (APR) for interest in PrEP. Because high-risk individuals by definition were homeless or unstably housed and used both methamphetamine and heroin, these individual predictor variables were not included in multivariable Poisson regression when adjusting for high-risk status. All statistical analyses were performed in R, version 1.1.456 R Studio (© 2009 – 2018 RStudio, Inc.).
Results
Analytic sample
In total, 432 people completed the 2019 survey. Of these 432 survey participants, 24 (5.6%) were excluded because they reported being HIV positive and 35 (8.1%) because they did not answer questions regarding their HIV status. An additional 25 (5.8%) were excluded because they did not report a history of injection drug use in the past 3 months. This yielded an analytic sample of 348 people who self-reported being HIV negative and had injected drugs in the past 3 months.
Awareness of PrEP and demographic characteristics
Of the 348 persons included in the analytic sample, 178 (51%) reported awareness of PrEP, and 3 reported current PrEP use (0.86% of the entire cohort, 1.7% of those who were PrEP aware). Demographic characteristics of surveyed participants are presented in Table I, stratified by PrEP awareness status. Across the entire sample, the median age was 36 years (IQR 30 – 44). The majority of respondents were male (62.1%), and 75.0% were white. Nearly three quarters were homeless or unstably housed (74.4%), and 9.5% reported a history of exchange sex. Heroin (87.6%) and methamphetamine (78.1%) were the most common drugs used in the past three months, with 76.4% of respondents reporting use of both heroin and methamphetamine, either together or separately, in the past three months. Two hundred and ten (60.3%) participants met the pre-specified definition of being high-risk for HIV. The majority of these individuals were PrEP aware (n=107, 60.1%); although less than 1% reported current PrEP use.
Table I.
Demographic Characteristics of People Who Inject Drugs and Access Harm Reduction Services at Public Health – Seattle & King County Syringe Service Programs
| All PWID (n=348) |
PrEP Aware (n= 178) |
PrEP Unaware (n= 170) |
p-valuea | |
|---|---|---|---|---|
|
High-risk for HIV (%)
(Unstably housed, use meth & heroin) |
210 (60.3) | 107 (60.1) | 103 (60.6) | 1.0 |
| Median age in years (IQR) | 36 (30 – 44) | 36 (30 – 43) | 36 (30 – 46) | 0.56b |
| Gender (%) | 0.10c | |||
| Man | 216 (62.1) | 103 (57.9) | 113 (66.5) | |
| Woman | 130 (37.4) | 73 (41.0) | 57 (33.5) | |
| Trans / Genderqueer / Nonbinary | 2 (0.6) | 2 (1.1) | 0 (0) | |
| Race (%) d | ||||
| White | 261 (75.0) | 131 (73.6) | 130 (76.5) | 0.62 |
| Black / African American | 20 (5.7) | 11 (6.2) | 9 (5.3) | 0.90 |
| Latinx/Hispanic | 28 (8.0) | 17 (9.6) | 11 (6.5) | 0.39 |
| Am. Indian / Alaska Native | 45 (12.9) | 21 (11.8) | 24 (14.1) | 0.63 |
| Asian / Pacific Isl. / Nat. Hawaiian | 27 (7.6) | 15 (8.4) | 12 (7.1) | 0.78 |
| Other | 9 (2.6) | 6 (3.4) | 3 (1.8) | 0.50c |
| Currently homeless (%) | 259 (74.4) | 130 (73.0) | 129 (75.9) | 0.63 |
| Exchange sex in past 12 months (%) | 33 (9.5) | 22 (12.4) | 11 (6.5) | 0.09 |
| MSM (%) e | 20 (5.7) | 16 (9.0) | 4 (2.4) | 0.02 |
| Drug(s) used in past 3 months (%) f | ||||
| Heroin | 305 (87.6) | 158 (88.8) | 147 (86.5) | 0.63 |
| Methamphetamine | 271 (78.1) | 128 (72.3) | 143 (84.1) | 0.01 |
| Goofball (meth & heroin) | 201 (57.8) | 100 (56.2) | 101 (59.4) | 0.62 |
| Crack cocaine | 69 (19.8) | 36 (20.2) | 33 (19.4) | 0.96 |
| Powder cocaine | 54 (15.6) | 30 (16.9) | 24 (14.2) | 0.59 |
| Speedball (cocaine & heroin) | 48 (13.8) | 31 (17.4) | 17 (10.0) | 0.06 |
| Fentanyl | 61 (17.7) | 24 (13.6) | 37 (21.9) | 0.06 |
| Other opiate medication | 47 (13.5) | 24 (13.5) | 23 (13.6) | 1.0 |
| Benzodiazepines / Downers | 87 (25) | 54 (30.3) | 33 (19.4) | 0.03 |
| Methadone or suboxone in past 3 months (%) g | 152 (43.7) | 91 (51.1) | 61 (35.9) | 0.006 |
| Alcohol use in past 3 months (%) | 121 (34.9) | 65 (36.7) | 56 (32.9) | 0.53 |
| Median number of days injected drugs in past 7 days (IQR) | 7 (5.0 – 7.0) | 7.0 (4.0 – 7.0) | 7.0 (7.0 – 7.0) | 0.10b |
| Shared syringes in past 3 months (%) | 50 (14.4) | 28 (15.7) | 22 (12.9) | 0.56 |
| Shared other injection equipment in past 3 months (%) | 160 (46.1) | 79 (44.4) | 81 (47.9) | 0.58 |
| Drug treatment in past 12 months (%) | 180 (51.7) | 104 (58.4) | 76 (44.7) | 0.01 |
| Health insurance (%) | 317 (91.1) | 162 (91.0) | 155 (91.2) | 1.0 |
| History of hepatitis C (%) | 153 (45.8) | 81 (46.0) | 72 (45.6) | 1.0 |
| STI in past 12 months (%) | 9 (2.6) | 6 (3.4) | 3 (1.8) | 0.50c |
| Jail or prison in past 12 months (%) | 131 (37.6) | 62 (34.8) | 69 (40.6) | 0.32 |
Chi-squared test used unless otherwise specified.
Wilcoxon rank sum test with continuity correction
Fisher exact test
Percentages may sum to >100%, as participants could select multiple options.
Proportion of male identifying individuals who reported sex with men in the past 12 months,
Drugs used by themselves in the past 3 months, including both injection and non-injection use.
Does not distinguish between those who were prescribed methadone or suboxone and those who used these drugs without a prescription.
Compared to PrEP-unaware participants, PrEP-aware participants were more likely to be MSM (9% vs. 2.4%, p=0.02), were more likely to report methadone or suboxone use in the past three months (51.1% vs. 35.9%, p=0.006), were more likely to have received any treatment for drug use in the past 12 months (58.4% vs. 44.7%, p=0.01), and were more likely to have used benzodiazepines or other “downers” in the past three months (30.3% vs. 19.4%, p=0.03). Conversely, participants who reported prior awareness of PrEP were somewhat less likely to report methamphetamine use than those who reported no awareness of PrEP (72.3% vs. 84.1%, p=0.01).
Correlates of interest in PrEP
Information on interest in PrEP was available for 341 individuals, 158 (46%) of whom reported being “very” or “somewhat” interested in taking PrEP to prevent HIV. In bivariate, unadjusted regression models, being homeless or unstably housed (PR 1.55, 95% CI 1.12 – 2.13), sharing injection equipment in the past 3 months (PR 1.37, 95% CI 1.09 – 1.73), and using methamphetamine (PR 1.66, 95% CI: 1.16 – 2.38), fentanyl (PR 1.41, 95% CI 1.10 – 1.80), or other opiates aside from heroin and fentanyl (PR 1.33, 95% CI 1.01 – 1.75) were associated with a higher prevalence of interest in PrEP. Similarly, PWID classified as high-risk for HIV had a 1.52 times higher prevalence of interest in PrEP than those who did not meet high-risk criteria (PR 1.52, 95% CI 1.17 – 1.97). Awareness of HIV PrEP was associated with a lower interest in PrEP (PR 0.58, 95% CI 0.45 – 0.74) (Table II).
Table II.
Association Between Demographic Characteristic and Interest in HIV Pre-Exposure Prophylaxis Among People Who Inject Drugs and Access Harm Reduction Services at Public Health – Seattle and King County Syringe Service Programs
| Unadjusted Prevalence Ratio (95% CI) |
p-value | Adjustedh Prevalence Ratio (95% CI) |
p-value | |
|---|---|---|---|---|
|
High-risk for HIV
(Unstably housed, use meth & heroin) |
1.52 (1.17, 1.97) | 0.002 | 1.41 (1.06, 1.88) | 0.02 |
| Age | 0.99 (0.98, 1.00) | 0.20 | ||
| Gender | ||||
| Men | Ref | -- | ||
| Woman | 0.96 (0.76, 1.20) | 0.70 | ||
| Trans / genderqueer / nonbinaryi | -- | -- | ||
| Race | ||||
| White | 0.89 (0.69, 1.14) | 0.36 | ||
| Black / African American | 1.08 (0.69, 1.71) | 0.73 | ||
| Latinx/Hispanic | 0.84 (0.52, 1.35) | 0.46 | ||
| Am. Indian / Alaska Native | 1.30 (0.81, 2.09) | 0.07 | ||
| Asian / Pacif. Isl. / Nat. Hawaiian | 1.27 (0.89, 1.80) | 0.18 | ||
| Other | 0.27 (0.04, 1.66) | 0.16 | ||
| Homeless j | 1.55 (1.12, 2.13) | 0.008 | -- | |
| Exchange Sex | 1.33 (0.97, 1.83) | 0.08 | ||
| MSM k | 0.66 (0.33, 1.29) | 0.22 | ||
| Drug(s) used in past 3 months | ||||
| Heroin | 1.12 (0.77, 1.63) | 0.54 | ||
| Methamphetaminej | 1.66 (1.16, 2.38) | 0.006 | -- | |
| Goofball (meth & heroin) | 1.25 (0.98, 1.59) | 0.08 | ||
| Crack cocaine | 0.92 (0.69, 1.24) | 0.60 | ||
| Powder cocaine | 0.95 (0.69, 1.31) | 0.75 | ||
| Speedball (cocaine & heroin) | 0.86 (0.59, 1.23) | 0.40 | ||
| Fentanyl | 1.41 (1.10, 1.80) | 0.006 | 1.13 (0.87, 1.43) | 0.40 |
| Other opiate medication | 1.33 (1.01, 1.75) | 0.04 | 1.28 (0.98, 1.67) | 0.07 |
| Benzodiazepines / Downers | 0.99 (0.76, 1.29) | 0.94 | ||
| Number of days injected in last 7 days | 1.04 (0.98, 1.10) | 0.21 | ||
| Shared syringes in past 3 months | 1.17 (0.88, 1.57) | 0.28 | ||
| Shared other injection equipment in past 3 months | 1.37 (1.09 1.73) | 0.007 | 1.14 (0.89, 1.45) | 0.31 |
| PrEP aware | 0.58 (0.45, 0.74) | <0.001 | 0.58 (0.45, 0.74) | <0.001 |
| STI in last 12 months | 0.96 (0.46, 2.01) | 0.92 | ||
| Drug treatment in past 12 months | 0.85 (0.68, 1.07) | 0.16 | ||
| Health insurance | 0.83 (0.59, 1.17) | 0.28 |
Multivariable adjusted model includes the following variables: high-risk for HIV, use of fentanyl in the past three months, use of other opioids in the past three months, sharing injection equipment in the past three months, and prior awareness of PrEP.
Number of transgender / genderqueer / nonbinary persons was too small to run regression model.
Variable not included in the adjusted model, despite statistical significance in bivariate analysis, as person who are high-risk are by definition homeless and use methamphetamine.
In comparison to men who did not report sex with other men in the past 12 months.
In a multivariable model, adjusting for fentanyl use, use of opiates other than heroin or fentanyl, sharing injection equipment in the past three months, and awareness of PrEP, individuals at high-risk for HIV continued to have a 41% higher prevalence of interest in PrEP when compared to those who did not meet the high-risk criteria (APR 1.41, 95% CI 1.06 – 1.88). In this same model, awareness of PrEP remained associated with a lower prevalence of interest in PrEP (APR 0.58, 95% CI 0.45, 0.74). Adjusted prevalence ratios for use of methamphetamine and homelessness were not obtained despite these variables showing statistical significance in bivariate regression, as high-risk individuals by definition used methamphetamine and were homeless.
Discussion
In this study of HIV-negative PWID seeking syringe services in Seattle, Washington, we found a very low frequency of PrEP use despite half of survey participants reporting awareness of PrEP and 46% reporting interest in PrEP. Although persons meeting our local a priori criteria for being at high-risk for HIV had a higher prevalence of interest in PrEP, the negative association we found between awareness of PrEP and interest in PrEP suggests increasing awareness of HIV PrEP among PWID may not be sufficient to promote PrEP uptake, and further efforts are needed to understand perceptions of risk for HIV and barriers and facilitators of PrEP use in this marginalized population.
The low prevalence of current PrEP use observed in our cohort is consistent with that reported in other studies of PWID. In a cross-sectional survey of 265 HIV-uninfected PWID in Baltimore, researchers reported that only 2 survey respondents were currently taking PrEP. (Sherman et al., 2019) Surveys of PWID in Philadelphia (Roth et al., 2019) and San Francisco (McFarland et al., 2020) report similarly low prevalence of PrEP use, 2.6% and 3.0% respectively, and a study of 152 SSP clients in Miami found that no participants were taking PrEP. (Jo et al., 2020) Although several of the aforementioned studies cite limited knowledge and awareness of PrEP as a major factor influencing PrEP uptake, our study found relatively high awareness of PrEP among PWID in comparison to other similar cohorts. (Jo et al., 2020; Kuo et al., 2016; Roth et al., 2019; Sherman et al., 2019; Suzan M Walters et al., 2017; S. M. Walters et al., 2017) One reason for this may be that our sample consisted of PWID who receive harm reduction services at health department affiliated SSPs and were therefore likely to be exposed to public health messaging, including messaging surrounding PrEP. Nevertheless, there was no appreciable difference in PrEP use between our sample and other representative samples of PWID (Jo et al., 2020; McFarland et al., 2020; Roth et al., 2019; Sherman et al., 2019) despite multiple stated risk factors for HIV among our survey respondents, including exchange sex and sharing of injection equipment. Moreover, we observed a negative association between awareness of PrEP and interest in taking PrEP, suggesting that awareness alone is not sufficient to promote interest and ultimately uptake of PrEP in this population.
While factors driving this inverse association require further investigation into the barriers and facilitators of PrEP use among PWID in Seattle, qualitative data from other geographic samples of PWID suggest that interest in PrEP is strongly driven by one’s perception of risk for HIV, and many PWID do not perceive themselves to be at risk despite the presence of multiple risk behaviors. (Allen et al., 2020; Bazzi et al., 2018; Biello et al., 2018; Footer et al., 2019) Similarly, qualitative studies have found that despite familiarity with PrEP, many PWID lack accurate knowledge of PrEP, including how it works, advantages and disadvantages of PrEP use, and indications for initiating PrEP, which may affect their interest and willingness to use PrEP to prevent HIV. (Allen et al., 2020; Bazzi et al., 2018; Biello et al., 2018; Kuo et al., 2016) Competing health priorities, (Bazzi et al., 2018; Biello et al., 2018) social stigma, (Carter et al., 2021; Footer et al., 2019) the potential cost of PrEP, (Allen et al., 2020) PrEP side effects, (Biello et al., 2018) unstable living situations leading to socio-structural adherence barriers, (Allen et al., 2020; Footer et al., 2019) negative prior experiences with the healthcare system,(Carter et al., 2021) social marginalization (Smith et al., 2021) and structural barriers within the healthcare system (Biello et al., 2018; Biello et al., 2021) have also been identified as barriers to PrEP uptake among PWID and may be contributing to the inverse association between PrEP awareness and interest observed in our study.
It is notable, however, that in our study meeting pre-specified local criteria for being at high-risk for HIV was associated with greater interest in PrEP, despite a high baseline awareness of PrEP in this group. While factors driving this association cannot be ascertained from our data, the association suggests that high-risk individuals likely perceive themselves to be at elevated risk for HIV. These findings are in keeping with a prior study from Baltimore, which showed that interest in PrEP was associated with meeting eligibility criteria for PrEP, (Sherman et al., 2019) and they are consistent with the aforementioned qualitative studies showing a strong association between perceived risk for HIV and interest in PrEP. (Allen et al., 2020; Bazzi et al., 2018; Biello et al., 2018; Footer et al., 2019)
Despite stated interest in PrEP among high-risk PWID in Seattle, no clear consensus on how to best deliver PrEP services to this population has emerged. (Bazzi et al., 2018) Prior studies have suggested that PWID-specific PrEP messaging and integration of PrEP into other services for PWID may facilitate uptake; (Allen et al., 2020; Bazzi et al., 2018) however, data are lacking on successful models for operationalizing PrEP for PWID at high-risk for HIV. If we were to assume that the proportion of PWID in our survey who met criteria for being high-risk for HIV (60.3%) was representative of the proportion of PWID in King County who are at elevated risk for HIV, then operationalizing PrEP delivery for this group would involve treating nearly 16,000 of the 26,500 PWID in the county with PrEP. (HIV/AIDS Epidemiology Report for King County and Washington State, 2018) While this may be an overestimate of those truly at highest risk for HIV, as more granular data on sexual practices and injection patterners are needed, this estimate does suggest that a large number of PWID in King County would benefit from PrEP use. While ongoing uncertainty as to the barriers and facilitators of PrEP uptake and sustained use exist within our local population of PWID, our findings support the general acceptability of HIV PrEP amongst high-risk PWID and further argue that urgent efforts are needed to investigate implementation strategies for the delivery of comprehensive HIV prevention services to those PWID who are both at highest risk for HIV and also most interested in the use of PrEP for HIV prevention.
There are several limitations to our study. All findings are based on cross-sectional survey data that relied on participant self-report. HIV status was not confirmed by laboratory testing, and therefore some degree of misclassification may exist. Furthermore, our results are subject to social desirability bias given that surveys were administered to PWID by SSP staff. Our definition of high-risk was based on characteristics of the 2018 cluster of linked HIV infections among homeless PWID in Seattle and does not take into account more granular risk data including condom use, type of sexual partners, and sharing of syringes and other injection equipment that place PWID at risk for HIV. As such, this definition of high-risk may be missing subsets of PWID who are at elevated risk for HIV based on specific sexual and injection risk behaviors. Additionally, combinations of injection drugs and their associated use patterns have been shown impact HIV risk factors (Schneider et al., 2020), and aside from methamphetamine and heroin, in conjunction with unstable housing, we did not examine the relationship between specific injection drug combinations and interest in PrEP. Finally, data presented in this study were obtained from a subset of PWID who are already accessing harm reduction services in Seattle and are likely not representative of all PWID in Seattle and King County. Given their engagement in harm reduction services, PWID in this sample may be more aware of other prevention interventions, including PrEP, and they may be more likely to report interest in other modalities for HIV prevention.
Conclusion
In this sample of HIV-negative PWID in Seattle, Washington, less than 1% were currently taking PrEP, 51% were PrEP aware, and 46% reported interest in PrEP. In comparison to the remainder of the sample, interest in PrEP was higher among a group of PWID meeting pre-specified risk criteria for HIV acquisition. Nevertheless, across the sample as a whole, awareness of PrEP was inversely associated with interest in PrEP. Our results suggest that increasing awareness of HIV PrEP among PWID may not be sufficient to promote PrEP uptake, and further efforts are needed to understand perceptions of risk for HIV, determinants of PrEP use, and investigate successful strategies for PrEP implementation and delivery in this marginalized population.
Acknowledgements
Authors would like to acknowledge the SSP clients and staff who participated in and conducted the 2019 PHSKC survey of SSP clients.
Funding
M.C. was supported in the work by training grants from the National Institute of Diabetes and Digestive and Kidney Diseases [5T32DK007742-22] and the National Institute of Allergy and Infectious Diseases [5T32AI007044-43].
Footnotes
Disclosures of interest
MAC: Nothing to disclose.
JDS: Has served on a hepatitis B advisory board for Gilead Sciences.
JT: Nothing to disclose.
AW: Nothing to disclose.
SNG: Nothing to disclose.
References
- Allen ST, O’Rourke A, Hamilton White R, Smith KC, Weir B, Lucas GM, … Grieb SM (2020). Barriers and Facilitators to PrEP Use Among People Who Inject Drugs in Rural Appalachia: A Qualitative Study. AIDS and Behavior, 24, 1942–1950. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Bazzi AR, Biancarelli DL, Childs E, Drainoni ML, Edeza A, Salhaney P, … Biello KB (2018). Limited Knowledge and Mixed Interest in Pre-Exposure Prophylaxis for HIV Prevention Among People Who Inject Drugs. AIDS Patient Care STDS, 32(12), 529–537. 10.1089/apc.2018.0126 [DOI] [PMC free article] [PubMed] [Google Scholar]
- Biello KB, Bazzi AR, Mimiaga MJ, Biancarelli DL, Edeza A, Salhaney P, … Drainoni ML (2018). Perspectives on HIV pre-exposure prophylaxis (PrEP) utilization and related intervention needs among people who inject drugs. Harm Reduct J, 15(1), 55. 10.1186/s12954-018-0263-5 [DOI] [PMC free article] [PubMed] [Google Scholar]
- Biello KB, Mimiaga MJ, Valente PK, Saxena N, & Bazzi AR (2021). The Past, Present, and Future of PrEP implementation Among People Who Use Drugs. Curr HIV/AIDS Rep, 18(4), 328–338. 10.1007/s11904-021-00556-z [DOI] [PMC free article] [PubMed] [Google Scholar]
- Burt RD, Tinsley J, & Glick SN (2017). A Decline in HIV Testing Among Persons Who Inject Drugs in the Seattle Area, 2004–2015. J Acquir Immune Defic Syndr, 75 Suppl 3, S346–S351. 10.1097/QAI.0000000000001409 [DOI] [PubMed] [Google Scholar]
- Carter G, Meyerson B, Rivers P, Crosby R, Lawrence C, Cope SD, … Grivois-Shah R (2021). Living at the Confluence of Stigmas: PrEP Awareness and Feasibility Among People Who Inject Drugs in Two Predominantly Rural States. AIDS Behav, 25(10), 3085–3096. 10.1007/s10461-021-03304-x [DOI] [PubMed] [Google Scholar]
- Centers for Disease Control and Prevention: US Public Health Service: Preexposure prophylaxis for the prevention of HIV infection in the United States—2017 Update: a clinical practice guideline. (2018). Retrieved October 4, 2019 from https://www.cdc.gov/hiv/pdf/risk/prep/cdc-hiv-prep-guidelines-2017.pdf
- Choopanya K, Martin M, Suntharasamai P, Sangkum U, Mock PA, Leethochawalit M, … Group, B. T. S. (2013). Antiretroviral prophylaxis for HIV infection in injecting drug users in Bangkok, Thailand (the Bangkok Tenofovir Study): a randomised, double-blind, placebo-controlled phase 3 trial. Lancet, 381(9883), 2083–2090. 10.1016/S0140-6736(13)61127-7 [DOI] [PubMed] [Google Scholar]
- Des Jarlais D, Sypsa V, Freelemyer J, Abagiu A, Arendt V, Broz D, … Wiessing L (2018). Complacency is the New Problem: Comparative Analysis of Recent Outbreaks of HIV Among Persons Who Inject Drugs in Europe and North America International AIDS Conference, Amsterdam, Netherlands. http://natap.org/2018/IAC/IAS2018GlobalOutbreaksPosterFinalopy.pdf [Google Scholar]
- Des Jarlais DC, Sypsa V, Feelemyer J, Abagiu AO, Arendt V, Broz D, … Wiessing L (2020). HIV outbreaks among people who inject drugs in Europe, North America, and Israel. Lancet HIV, 7(6), e434–e442. 10.1016/S2352-3018(20)30082-5 [DOI] [PMC free article] [PubMed] [Google Scholar]
- Footer KHA, Lim S, Rael CT, Greene GJ, Carballa-Diéguez A, Giguere R, … Sherman SG (2019). Exploring new and existing PrEP modalities among female sex workers and women who inject drugs in a U.S. city. AIDS Care, 31(10), 1207–1213. 10.1080/09540121.2019.1587352 [DOI] [PMC free article] [PubMed] [Google Scholar]
- Glick SN, Burt R, Kummer K, Tinsley J, Banta-Green CJ, & Golden MR (2018). Increasing methamphetamine injection among non-MSM who inject drugs in King County, Washington. Drug Alcohol Depend, 182, 86–92. 10.1016/j.drugalcdep.2017.10.011 [DOI] [PMC free article] [PubMed] [Google Scholar]
- Golden MR, Lechtenberg R, Glick SN, Dombrowski J, Duchin J, Reuer JR, … Buskin SE (2019). Outbreak of Human Immunodeficiency Virus Infection Among Heterosexual Persons Who Are Living Homeless and Inject Drugs - Seattle, Washington, 2018. MMWR Morb Mortal Wkly Rep, 68(15), 344–349. 10.15585/mmwr.mm6815a2 [DOI] [PMC free article] [PubMed] [Google Scholar]
- Harris PA, Taylor R, Minor BL, Elliott V, Fernandez M, O’Neal L, … Consortium, R. (2019). The REDCap consortium: Building an international community of software platform partners. J Biomed Inform, 95, 103208. 10.1016/j.jbi.2019.103208 [DOI] [PMC free article] [PubMed] [Google Scholar]
- Harris PA, Taylor R, Thielke R, Payne J, Gonzalez N, & Conde JG (2009). Research electronic data capture (REDCap)--a metadata-driven methodology and workflow process for providing translational research informatics support. J Biomed Inform, 42(2), 377–381. 10.1016/j.jbi.2008.08.010 [DOI] [PMC free article] [PubMed] [Google Scholar]
- HIV/AIDS Epidemiology Report for King County and Washington State. (2018). Public Health Seattle and King County HIV/AIDS Epidemiology Unit & Washington State Department of Health Infectious Disease Assessment Unit. www.kingcounty.gov/hivepi
- Jenkins LM, Banta-Green CJ, Maynard C, Kingston S, Hanrahan M, Merrill JO, & Coffin PO (2011). Risk factors for nonfatal overdose at Seattle-area syringe exchanges. J Urban Health, 88(1), 118–128. 10.1007/s11524-010-9525-6 [DOI] [PMC free article] [PubMed] [Google Scholar]
- Jo Y, Bartholomew TS, Doblecki-Lewis S, Rodriguez A, Forrest DW, Tomita-Barber J, … Tookes HE (2020). Interest in linkage to PrEP among people who inject drugs accessing syringe services; Miami, Florida. PLoS One, 15(4), e0231424. 10.1371/journal.pone.0231424 [DOI] [PMC free article] [PubMed] [Google Scholar]
- Kuo I, Olsen H, Patrick R, Phillips G, Magnus M, Opoku J, … Greenberg A (2016). Willingness to use HIV pre-exposure prophylaxis among community-recruited, older people who inject drugs in Washington, DC. Drug Alcohol Depend, 164, 8–13. 10.1016/j.drugalcdep.2016.02.044 [DOI] [PubMed] [Google Scholar]
- McFarland W, Lin J, Santos GM, Arayasirikul S, Raymond HF, & Wilson E (2020). Low PrEP Awareness and Use Among People Who Inject Drugs, San Francisco, 2018. AIDS Behav, 24(5), 1290–1293. 10.1007/s10461-019-02682-7 [DOI] [PubMed] [Google Scholar]
- Peavy KM, Banta-Green CJ, Kingston S, Hanrahan M, Merrill JO, & Coffin PO (2012). “Hooked on” prescription-type opiates prior to using heroin: results from a survey of syringe exchange clients. J Psychoactive Drugs, 44(3), 259–265. 10.1080/02791072.2012.704591 [DOI] [PubMed] [Google Scholar]
- Peters PJ, Pontones P, Hoover KW, Patel MR, Galang RR, Shields J, … Team, I. H. O. I. (2016). HIV Infection Linked to Injection Use of Oxymorphone in Indiana, 2014–2015. N Engl J Med, 375(3), 229–239. 10.1056/NEJMoa1515195 [DOI] [PubMed] [Google Scholar]
- Roth A, Tran N, Piecara B, Welles S, Shinefeld J, & Brady K (2019). Factors Associated with Awareness of Pre-exposure Prophylaxis for HIV Among Persons Who Inject Drugs in Philadelphia: National HIV Behavioral Surveillance, 2015. AIDS Behav, 23(7), 1833–1840. 10.1007/s10461-018-2293-0 [DOI] [PubMed] [Google Scholar]
- Roth AM, Aumaier BL, Felsher MA, Welles SL, Martinez-Donate AP, Chavis M, & Van Der Pol B (2018). An Exploration of Factors Impacting Preexposure Prophylaxis Eligibility and Access Among Syringe Exchange Users. Sex Transm Dis, 45(4), 217–221. 10.1097/OLQ.0000000000000728 [DOI] [PubMed] [Google Scholar]
- Schneider KE, White RH, Musci RJ, O’Rourke A, Kilkenny ME, Sherman SG, & Allen ST (2020). The Relationship Between Polysubstance Injection Drug Use, HIV Risk Behaviors, and Interest in Pre-Exposure Prophylaxis (PrEP) Among People Who Inject Drugs in Rural West Virginia. J Stud Alcohol Drugs, 81(6), 740–749. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Sherman SG, Schneider KE, Park JN, Allen ST, Hunt D, Chaulk CP, & Weir BW (2019). PrEP awareness, eligibility, and interest among people who inject drugs in Baltimore, Maryland. Drug Alcohol Depend, 195, 148–155. 10.1016/j.drugalcdep.2018.08.014 [DOI] [PMC free article] [PubMed] [Google Scholar]
- Smith M, Elliott L, Hutchinson SJ, Metcalfe R, Flowers P, & McAuley A (2021). Perspectives on pre-exposure prophylaxis for people who inject drugs in the context of an hiv outbreak: A qualitative study. Int J Drug Policy, 88, 103033. 10.1016/j.drugpo.2020.103033 [DOI] [PubMed] [Google Scholar]
- Walters SM, Reilly KH, Neaigus A, & Braunstein S (2017). Awareness of pre-exposure prophylaxis (PrEP) among women who inject drugs in NYC: the importance of networks and syringe exchange programs for HIV prevention. Harm Reduction Journal, 14(1). [DOI] [PMC free article] [PubMed] [Google Scholar]
- Walters SM, Rivera AV, Starbuck L, Reilly KH, Boldon N, Anderson BJ, & Braunstein S (2017). Differences in Awareness of Pre-exposure Prophylaxis and Post-exposure Prophylaxis Among Groups At-Risk for HIV in New York State: New York City and Long Island, NY, 2011–2013. J Acquir Immune Defic Syndr, 75 Suppl 3, S383–S391. 10.1097/QAI.0000000000001415 [DOI] [PubMed] [Google Scholar]