Identification of a Syndemic of Blood-Borne Disease Transmission and Injection Drug Use Initiation at the US-Mexico Border

Context and correlates of providing assistance with someone's first injection in the AIDS linked to the IntraVenous Experience cohort, Baltimore, MD

BACKGROUND

The social processes around initiating injection may be well-suited to intervention, yet there is substantial heterogeneity in the reported experiences of people who inject drugs (PWID) who assist with another individual's first drug injection. We aimed to describe the lifetime prevalence and context of providing initiation assistance among a cohort of PWID.

METHODS

Participants of the AIDS Linked to the IntraVenous Experience (ALIVE) cohort of PWID in Baltimore, Maryland (n=848) were surveyed during 2019-2020 about assisting with another person's first injection. Associations between factors related to injection risk and history of providing assistance were estimated using logistic regression models adjusted for sociodemographic and behavioral characteristics.

RESULTS

At baseline, participants were primarily male (66.1%), black (82.9%), aged a median of 42 years, and had been injecting a median of 18 years. Overall, 19% (n=157) of participants reported ever providing assistance for a median of 2 people (Interquartile Range: 1-4). Having hepatitis C infection (adjusted Odds Ratio [95% Confidence Interval]: 2.5 [1.4-4.6]), syringe sharing (2.2 [1.2-3.9]), and injecting ≥3 times per day (2.0 [1.2-3.4]) at study enrollment were associated with a history of assistance. Participants primarily assisted friends (58.0%), acquaintances (29.9%), and partners (21.7%). Common reasons for assisting were the other person's lack of injection knowledge (73.7%) or sharing drugs (44.9%). Additional reasons included to prevent injury.

CONCLUSION

PWID with a history of assisting with another person's first injection exhibited heightened vulnerability to infections and more frequent substance use. Expanding implementation of interventions with an emphasis on harm reduction is needed.

Gender and the first-time provision of injection initiation assistance among people who inject drugs across two distinct North American contexts: Tijuana, Mexico and Vancouver, Canada

INTRODUCTION

Injection drug use initiation is commonly facilitated by other people who inject drugs (PWID). We investigated how the gender of PWID influences their risk of providing initiation assistance to others across two distinct geo-cultural settings.

METHODS

Data were drawn from two prospective cohorts in Tijuana, Mexico and Vancouver, Canada which conducted semi-annual interviews within the PReventing Injecting by Modifying Existing Responses (PRIMER) study. Participants consisted of PWID who had reported never providing injection initiation assistance at baseline. We then conducted site-specific discrete-time survival analyses assessing the relationship between gender and other relevant covariates (e.g. age and past 6-month sex work) on the risk of the first reported instance of providing initiation assistance.

RESULTS

Of 1988 PWID (Tijuana: n = 596; Vancouver: n = 1392), 256 (43%) and 511 (36.7%) participants were women, and 42 (1.7%) and 78 (1.6%) reported recent injection initiation assistance across a median of three and two follow-up visits, respectively. Women had a lower risk of providing injection initiation assistance for the first time in Tijuana (adjusted hazard ratio = 0.52, 95% confidence interval 0.27-0.99), but not in Vancouver. Gendered pathways, like sex work, were associated with providing initiation assistance for the first time in Vancouver (adjusted hazard ratio = 1.97, 95% confidence interval 1.08-3.61).

DISCUSSION AND CONCLUSIONS

Women in Tijuana, but not Vancouver, were less likely to provide first-time initiation assistance among PWID. These results can inform gender- and site-specific prevention efforts aimed at reducing transitions into drug injecting across geographic contexts.

Involvement of people who inject drugs in injection initiation events: a cross-sectional analysis identifying similarities and differences across three North American settings

OBJECTIVES

People who inject drugs (PWID) play an integral role in facilitating the entry of others into injection drug use (IDU). We sought to assess factors influencing PWID in providing IDU initiation assistance across three distinct North American settings and to generate pooled measures of risk.

DESIGN

We employed data from three PWID cohort studies participating in PReventing Injecting by Modifying Existing Responses (PRIMER), for this cross-sectional analysis.

SETTING

Tijuana, Mexico; San Diego, USA; Vancouver, Canada.

PARTICIPANTS

A total of 2944 participants were included in this study (Tijuana: n=766, San Diego: n=353, Vancouver: n=1825).

MEASUREMENTS

The outcome was defined as recently (ie, past 6 months) assisting in an IDU initiation event. Independent variables of interest were identified from previous PRIMER analyses. Site-specific multiple modified Poisson regressions were fit. Pooled relative risks (pRR) were calculated and heterogeneity across sites was assessed via linear random effects models.

RESULTS

Evidence across all three sites indicated that having a history of providing IDU initiation assistance (pRR: 4.83, 95% CI: 3.49 to 6.66) and recently being stopped by law enforcement (pRR: 1.49, 95% CI: 1.07 to 2.07) were associated with a higher risk of providing assistance with IDU initiation; while recent opioid agonist treatment (OAT) enrolment (pRR: 0.64, 95% CI: 0.43 to 0.96) and no recent IDU (pRR: 0.21, 95% CI: 0.07 to 0.64) were associated with a lower risk. We identified substantial differences across site in the association of age (I²: 52%), recent housing insecurity (I²: 39%) and recent non-injection heroin use (I²: 78%).

CONCLUSION

We identified common and site-specific factors related to PWID's risk of assisting in IDU initiation events. Individuals reporting a history of assisting IDU initiations, being recently stopped by law enforcement, and recently injecting methamphetamine/speedball were more likely to have recently assisted an IDU initiation. Whereas those who reported not recently engaging in IDU and those recently enrolled in OAT were less likely to have done so. Interventions and harm reduction strategies aimed at reducing the harms of IDU should incorporate context-specific approaches to reduce the initiation of IDU.

Investigating a bidirectional relationship between overdose and provision of injection initiation assistance among persons who inject drugs in Vancouver, Canada and Tijuana, Mexico

BACKGROUND

Individuals who initiate injection drug use often receive assistance from an injection-knowledgeable peer. Persons who assist peers in injection initiation events often inject frequently, which heightens overdose risk. As such, overdose and injection initiation events may be correlated. To explore a potential relationship, we assessed temporal associations between experiencing a non-fatal overdose and assisting others in initiating injection drug use among persons who inject drugs in two North American cities - Vancouver, Canada and Tijuana, Mexico.

METHODS

From 2014 to 2018, this retrospective cohort study included people who inject drugs from Vancouver (n=1332) and Tijuana (n=666) who completed a baseline and six-month follow-up interview. Within each site, we assessed bidirectional temporal associations using two separate multivariable logistic regression models: for model 1, recent provision of injection initiation assistance (at six months) was the outcome and recent overdose (at baseline) was the exposure; for model 2, recent overdose (at six months) was the outcome and recent provision of injection initiation assistance (at baseline) was the exposure. Both models adjusted for potential confounders.

RESULTS

Vancouver-based participants reporting overdose at baseline had 163% greater odds of reporting provision of injection initiation assistance at follow-up (adjusted Odds Ratio [aOR] 2.63; 95% Confidence Interval [CI] 1.41-4.90); while participants reporting provision of injection initiation assistance at baseline had 89% greater odds of reporting a non-fatal overdose at follow-up (aOR 1.89; 95% CI 1.00-3.57). Among Tijuana-based participants, we did not observe a statistically significant association in either direction.

CONCLUSION

Findings in Vancouver suggest that injection initiation assistance and overdose are bidirectionally-associated phenomena. The present findings highlight the need for interventions that ensure that persons who provide injection initiation assistance are given overdose prevention support, both for themselves and for those they assist to initiate injection drug use. While our Tijuana-based results did not suggest a bidirectional relationship, preventative approaches should nonetheless be undertaken.

Sex differences in the multilevel determinants of injection risk behaviours among people who inject drugs in Tijuana, Mexico

INTRODUCTION AND AIMS

HIV and hepatitis C virus transmission among people who inject drugs (PWID) is fuelled by personal and environmental factors that vary by sex. We studied PWID in Mexico to identify sex differences in multilevel determinants of injection risk.

DESIGN AND METHODS

From 2011 to 2013, 734 PWID (female: 277, male: 457) were enrolled into an observational cohort study in Tijuana. Participants completed interviews on injection and sexual risks. Utilising baseline data, we conducted multiple generalised linear models stratified by sex to identify factors associated with injection risk scores (e.g. frequency of injection risk behaviours).

RESULTS

For both sexes, difficult access to sterile syringes was associated with elevated injection risk (b = 1.24, 95% confidence interval [CI] 1.16-1.33), using syringes from a safe source (e.g. needle exchange programs) was associated with lower injection risk (b = 0.87, 95% CI 0.82-0.94), and for every one-unit increase in safe injection self-efficacy we observed a 20% decrease in injection risk (b = 0.80, 95% CI 0.76-0.84). Females had a higher safe injection self-efficacy score compared to males (median 2.83, interquartile range 2.2-3 vs. median 2.83, interquartile range 2-3; P = 0.01). Among females, incarceration (b = 1.22, 95% CI 1.09-1.36) and police confiscation of syringes in the past 6 months (b = 1.16, 95% CI 1.01-1.33) were associated with elevated injection risk. Among males, sex work (b = 1.16, 95% CI 1.04-1.30) and polysubstance use in the past 6 months (b = 1.22, 95% CI 1.13-1.31) were associated with elevated injection risk.

DISCUSSION AND CONCLUSIONS

Interventions to reduce HIV and hepatitis C virus transmission among PWID in Tijuana should be sex-specific and consider multilevel determinants of injection risk to create safer drug use environments.

Prevalence and Correlates of Providing and Receiving Assistance With the Transition to Injection Drug Use

Preventing the transition to injection drug use is an important public health goal, as people who inject drugs (PWID) are at high risk for overdose and acquisition of infectious disease. Initiation into drug injection is primarily a social process, often involving PWID assistance. A better understanding of the epidemiology of this phenomenon would inform interventions to prevent injection initiation and to enhance safety when assistance is provided. We conducted a systematic review of the literature to 1) characterize the prevalence of receiving (among injection-naive persons) and providing (among PWID) help or guidance with the first drug injection and 2) identify correlates associated with these behaviors. Correlates were organized as substance use behaviors, health outcomes (e.g., human immunodeficiency virus infection), or factors describing an individual's social, economic, policy, or physical environment, defined by means of Rhodes' risk environments framework. After screening of 1,164 abstracts, 57 studies were included. The prevalence of receiving assistance with injection initiation (help or guidance at the first injection) ranged 74% to 100% (n = 13 estimates). The prevalence of ever providing assistance with injection initiation varied widely (range, 13%-69%; n = 13 estimates). Injecting norms, sex/gender, and other correlates classified within Rhodes' social risk environment were commonly associated with providing and receiving assistance. Nearly all PWID receive guidance about injecting for the first time, whereas fewer PWID report providing assistance. Substantial clinical and statistical heterogeneity between studies precluded meta-analysis, and thus local-level estimates may be necessary to guide the implementation of future psychosocial and sociostructural interventions. Further, estimates of providing assistance may be downwardly biased because of social desirability factors.

Recent incarceration and risk of first-time injection initiation assistance: A prospective cohort study of persons who inject drugs

BACKGROUND

Given the prevalence and harms of incarceration among persons who inject drugs (PWID) and their role in injection drug use initiation, we aimed to investigate whether recent incarceration influences the likelihood PWID assist others in their first-ever injection.

METHODS

Prospective cohort study of PWID in Vancouver, Canada who had their PReventing Injecting by Modifying Existing Responses (PRIMER) baseline visit between December 2014 and May 2017, reported never providing injection initiation assistance previously, and had ≥1 follow-up visit. The primary outcome, provision of injection initiation assistance, was defined via self-report as helping anybody inject for the first time in the past six months. The primary exposure was recent incarceration, i.e., self-report of being jailed, imprisoned or detained in the past six months. Participants were assessed biannually until November 2017, drop-out, or their first report of the primary outcome.

RESULTS

1,199 PWID (62.1% male; mean (SD) age, 44.4 (12.3) years) were included in our study. Across 4,171 follow-up visits, 67 participants (5.6%) reported providing injection initiation assistance. The proportion of participants reporting recent incarceration varied between 2.4% to 5.1% per follow-up visit. Based on a multivariable discrete-time proportional hazards regression analysis, recent incarceration was associated with an increased risk of providing injection initiation assistance during the same six-month period (adjusted hazard ratio, 2.64; 95% CI, 1.19 to 5.86).

CONCLUSIONS

The observed association between recent incarceration and risk of providing injection initiation assistance suggests that incarceration could be contributing to the expansion of injection drug use practices within vulnerable populations over time.

Pediatric meningitis due to Neisseria meningitidis, Streptococcus pneumoniae and Group B Streptococcus in Tijuana, Mexico: active/prospective surveillance, 2005-2018

Introduction

In Mexico, Neisseria meningitidis is considered to be a rare cause of bacterial meningitis (BM), however, one national publication using active surveillance has suggested the opposite. Group B Streptococcus (GBS) is also considered to be infrequent in young infants as a cause of BM in central Mexico. Streptococcus pneumoniae vaccination using the 13-valent conjugate vaccine (PCV13) started in our region in May 2012. We focused our research on whether N. meningitidis and GBS are important causes of BM, and to examine the effectiveness of PCV13 on pneumococcal BM.

Methods

From October 2005 to September 2018, active/prospective surveillance looking for all patients admitted with suspected BM <16 years of age was performed at the Tijuana, Mexico, General Hospital. Tijuana, Mexico to San Diego, Unites States of America (USA), is the most transited border in the world. Isolation of pathogens was by either conventional culture or Real Time-polymerase chain reaction (RT-PCR), all patients were followed during and 3 months after discharge, and a descriptive analysis was performed. The effectiveness of PCV13 was determined by comparing the proportion of cases per month on pneumococcal BM before and after its implementation.

Results

There were 86 confirmed BM cases. N. meningitidis was the leading cause (60.5%, and 61.5% caused by serogroup C), followed by S. pneumoniae (18.6%). PCV13 effectiveness on pneumococcal BM was of 64.3% and was associated with the disappearance of serotype 19A. A total of 22 infants <3 months old had BM; GBS was the leading cause at this age group (27.3%), followed by N. meningitidis (22.7%). The overall mortality was 24%.

Conclusions

BM by N. meningitidis is endemic in Tijuana, Mexico, and meningococcal vaccination should be seriously considered in the region. PCV13 is currently showing high effectiveness on pneumococcal BM, and we need to continue active surveillance to see whether maternal screening/prophylaxis for GBS should also be introduced in the region.