It’s difficult to develop infectious disease interventions (such as for HIV) for overlapping high-risk populations such as people who inject drugs, men who have sex with men, and female sex workers, where there are multiple transmission routes. Recent advances in dynamic modelling of coinfection epidemics could disentangle the contributions of different risk groups and behaviours to help develop more efficient and effective prevention interventions.

Background

Recent reports indicated declines in hepatitis C virus (HCV) testing during the first half of 2020 in the United States due to coronavirus disease 2019 (COVID-19), but the longer-term impact on HCV testing and treatment is unclear.

Methods

We obtained monthly state-level volumes of HCV antibody, RNA and genotype testing, and HCV treatment initiation, stratified by age and gender, spanning January 2019 until December 2020 from 2 large national laboratories. We performed segmented regression analysis for each state from a mixed-effects Poisson regression model with month as the main fixed predictor and state as a random intercept.

Results

During the pre-COVID-19 period (January 2019-March 2020), monthly HCV antibody and genotype tests decreased slightly whereas RNA tests and treatment initiations remained stable. Between March and April 2020, there were declines in the number of HCV antibody tests (37% reduction, P < .001), RNA tests (37.5% reduction, P < .001), genotype tests (24% reduction, P = .023), and HCV treatment initiations (31%, P < .001). Starting April 2020 through the end of 2020, there were significant increases in month-to-month HCV antibody (P < .001), RNA (P = .035), and genotype tests (P = .047), but only antibody testing rebounded to pre-COVID-19 levels. HCV treatment initiations remained low after April 2020 throughout the remainder of the year.

Conclusions

HCV testing and treatment dropped by >30% during April 2020 at the start of the COVID-19 pandemic, but although HCV testing increased again later in 2020, HCV treatment rates did not recover. Efforts should be made to link HCV-positive patients to treatment and revitalize HCV treatment engagement by healthcare providers.

Objective

We aim to use conditional or moderated mediation to simultaneously test how and for whom an injection risk intervention was efficacious at reducing receptive needle sharing among female sex workers who inject drugs (FSWs-IDUs) in Mexico.

Methods

Secondary analysis of data from a randomized trial. A total of 300 FSW-IDUs participated in Mujer Mas Segura in Ciudad Juarez, Mexico, and were randomized to an interactive injection risk intervention or a didactic injection risk intervention. We measured safe injection self-efficacy as the hypothesized mediator and policing behaviors (being arrested and syringe confiscation) as hypothesized moderators. In total, 213 women provided complete data for the current analyses.

Results

Conditional (moderated) mediation showed that the intervention affected receptive needle sharing through safe injection self-efficacy among women who experienced syringe confiscation. On average, police syringe confiscation was associated with lower safe injection self-efficacy (p = .04). Among those who experienced syringe confiscation, those who received the interactive (vs. didactic) intervention reported higher self-efficacy, which in turn predicted lower receptive needle sharing (p = .04).

Conclusions

Whereas syringe confiscation by the police negatively affected safe injection self-efficacy and ultimately injection risk behavior, our interactive intervention helped to "buffer" this negative impact of police behavior on risky injection practices. The theory-based, active skills building elements included in the interactive condition, which were absent from the didactic condition, helped participants' self-efficacy for safer injection in the face of syringe confiscation.

Objective

Until the early 2000s, there was only one needle exchange program (NEP) offered in Mexico. In 2004, the second Mexican NEP opened in Tijuana, but its utilization has not been studied. We studied predictors of initiating NEP during its early expansion in Tijuana, Mexico.

Methods

From April 2006 to April 2007, people who inject drugs (PWID) residing in Tijuana who had injected within the last month were recruited using respondent-driven sampling. Weighted Poisson regression incorporating generalized estimating equations was used to identify predictors of initiating NEP, while accounting for correlation between recruiter and recruits.

Results

NEP uptake increased from 20% at baseline to 59% after 6 months. Among a subsample of PWID not accessing NEP at baseline (n = 480), 83% were male and median age was 37 years (Interquartile Range: 32-43). At baseline, 4.4% were HIV-infected and 5.9% had syphilis titers >1:8. In multivariate models, factors associated with NEP initiation (p < .05) were attending shooting galleries (Adjusted Relative Risk [ARR]: 1.54); arrest for track-marks (ARR: 1.38); having a family member that ever used drugs (ARR: 1.37); and having a larger PWID network (ARR: 1.01 per 10 persons). NEP initiation was inversely associated with obtaining syringes at pharmacies (ARR: .56); earning >2500 pesos/month (ARR: .66); and reporting needle sharing (ARR: .71).

Conclusions

Uptake of NEP expansion in Tijuana was vigorous among PWID. We identified a range of factors that influenced the likelihood of NEP initiation, including police interaction. These findings have important implications for the scale-up of NEP in Mexico.

Introduction

Among people who inject drugs (PWID), polysubstance use has been associated with fatal and non-fatal overdose (NFOD). However, the risk of overdose due to the cumulative number of various recently used drug types remains unexplored. We estimated the risk of NFOD for different polysubstance use categories among PWID in Tijuana, Mexico.

Methods

Data came from 661 participants followed for 2 years in Proyecto El Cuete-IV, an ongoing prospective cohort of PWID. A multivariable Cox model was used to assess the cumulative impact of polysubstance use on the time to NFOD. We used the Cochran-Armitage test to evaluate a dose-response relationship between number of polysubstance use categories and NFOD.

Results

We observed 115 NFOD among 1029.2 person-years of follow-up (incidence rate: 11.2 per 100 person-years; 95% confidence interval [CI] 9.3-13.3). Relative to those who used one drug class, the adjusted hazard ratio of NFOD for individuals reporting using two drug classes was 1.11 (95% CI 0.69-1.79), three drug classes was 2.00 (95% CI 1.16-3.44) and for those reporting three compared to two was 1.79 (95% CI 1.09-2.97). A significant Cochran-Armitage trend test (P < 0.001) suggested a dose-response relationship.

Discussion and conclusions

Polysubstance use was associated with increased risk of NFOD with a dose-response relationship over 2 years. We identified a subgroup of PWID at high risk of NFOD who reported concurrent use of opioids, stimulants and benzodiazepines. Prioritising tailored harm reduction and overdose prevention interventions for PWID who use multiple substances in Tijuana is needed.

We studied mechanisms driving gender differences in HIV incidence among 651 women and men who inject drugs (PWID) in Tijuana, Mexico, hypothesizing that sex work will mediate the association between female gender and HIV incidence. Of 43 HIV seroconversions occurring between 2011 and 2018, 8.8% were among females and 5.2% among males. HIV incidence density was significantly higher among females versus males (1.75 per 100 person years [PY], 95% CI 1.16-2.66, vs. 0.95 per 100 PY, 95% CI 0.62-1.47). Factors significantly associated with HIV seroconversion were: sex work (adjusted hazard ratio [aHR] = 2.25, 95% CI 1.05-4.80); methamphetamine injection (aHR = 2.30, 95% CI 1.12-4.73); and methamphetamine and heroin co-injection in the past six months (aHR = 2.26, 95% CI 1.23-4.15). In mediation analyses, sex work mediated a substantial proportion (84.3%) of the association between female gender and HIV incidence. Interventions should target female PWID who engage in sex work to reduce gender-related disparities in HIV incidence.

Introduction. Needle and syringe programs (NSP) reduce syringe sharing and HIV transmission among people who inject drugs (PWID). However, their effectiveness relies on sufficient individual and population level coverage. In Tijuana, Mexico, the Global Fund (GF) supported NSP during 10/2011-12/2013, but withdrew funds at the end of 2013 following Mexico’s re-classification as an upper-middle income country. Objective. We tested the hypothesis of higher NSP access and lower receptive syringe sharing among PWID in Tijuana during the GF support period compared to pre-GF initiation and post-GF withdrawal. Method. We used data from an ongoing cohort study of PWID in Tijuana (03/2011-10/2015) to implement a segmented regression analysis investigating changes in the self-reported probability of NSP access, reported difficulty in finding sterile syringes and receptive syringe sharing before GF initiation and after GF discontinuation. Results. We found a large significant increase in the probability of NSP access (+.07) and decrease in receptive syringe sharing (-.23) right after GF initiation, which continued over the GF period. Subsequently, we found a significant decline in NSP access (-.05) and an increase in receptive syringe sharing (+.02) right after post-GF withdrawal, which continued thereafter. Discussion and conclusion. We demonstrated significant temporal changes in NSP access and receptive syringe sharing among PWID in Tijuana after GF initiation and withdrawal consistent with our hypothesis. Coordinated efforts with local authorities are needed to sustain major coverage NSP in settings receiving GF or external aid to guarantee continuity of harm reduction services and prevent reinside in risk behaviors associated with HIV transmission.

This study involved evaluation of the short-term impact of the RHANI Wives HIV intervention among wives at risk for HIV from husbands in Mumbai, India. A two-armed cluster RCT was conducted with 220 women surveyed on marital sex at baseline and 4-5 month follow-up. RHANI Wives was a multisession intervention focused on safer sex, marital communication, gender inequities and violence; control participants received basic HIV prevention education. Generalized linear mixed models were conducted to assess program impact, with cluster as a random effect and with time, treatment group, and the time by treatment interaction as fixed effects. A significant time by treatment effect on proportion of unprotected sex with husband (p = 0.01) was observed, and the rate of unprotected sex for intervention participants was lower than that of control participants at follow-up (RR = 0.83, 95 % CI = 0.75, 0.93). RHANI Wives is a promising model for women at risk for HIV from husbands.

Introduction

Police officers are at an elevated risk for needle-stick injuries (NSI), which pose a serious and costly occupational health risk for HIV and viral hepatitis. However, research on NSIs among police officers is limited, especially in low- and middle-income countries. Despite the legality of syringe possession in Mexico, half of people who inject drugs (PWID) in Tijuana report extrajudicial syringe-related arrests and confiscation by police, which has been associated with needle-sharing and HIV infection. We assessed the prevalence and correlates of NSIs among Tijuana police officers to inform efforts to improve occupational safety and simultaneously reduce HIV risks among police and PWID.

Methods

Tijuana's Department of Municipal Public Safety (SSPM) is among Mexico's largest. Our binational, multi-sectoral team analyzed de-identified data from SSPM's 2014 anonymous self-administered occupational health survey. The prevalence of NSI and syringe disposal practices was determined. Logistic regression with robust variance estimation via generalized estimating equations identified factors associated with ever having an occupational NSI.

Results

Approximately one-quarter of the Tijuana police force was given the occupational health survey (N=503). Respondents were predominantly male (86.5%) and ≤35 years old (42.6%). Nearly one in six officers reported ever having a NSI while working at SSPM (15.3%), of whom 14.3% reported a NSI within the past year. Most participants reported encountering needles/syringes while on duty (n=473, 94%); factors independently associated with elevated odds of NSIs included frequently finding syringes that contain drugs (adjusted odds ratio (AOR): 2.98; 95% confidence interval (CI): 1.56-5.67) and breaking used needles (AOR: 2.25; 95% CI: 1.29-3.91), while protective factors included being willing to contact emergency services in case of NSIs (AOR: 0.39; 95% CI: 0.22-0.69), and wearing needle-stick resistant gloves (AOR: 0.43; 95% CI: 0.19-0.91).

Conclusions

Tijuana police face an elevated and unaddressed occupational NSI burden associated with unsafe syringe-handling practices, exposing them to substantial risk of HIV and other blood-borne infections. These findings spurred the development and tailoring of training to reduce NSI by modifying officer knowledge, attitudes and enforcement practices (e.g. syringe confiscation) - factors that also impact HIV transmission among PWID and other members of the community.

Objectives. To characterize the effects of the onset of the COVID-19 pandemic on the risk environment of people who use drugs (PWUD) in Tijuana, Mexico. Methods. We used intensive participant-observation ethnography among street-based PWUD and key informants, such as frontline physicians and harm reductionists. Results. PWUD described an unprecedented cessation of police violence and extortion during the initial pandemic-related lockdown, though this quickly reversed and police violence worsened. Government-provided housing and medical treatment with methadone were temporarily provided to PWUD in a dedicated clinic, yet only for PWUD with COVID-19 symptoms. Concurrently, non‒COVID-19‒related hospital care became virtually inaccessible, and many PWUD died of untreated, chronic illnesses, such as hepatitis C, and soft-tissue infections. Border closures, decreases in social interaction, and reduced drug and sex tourism resulted in worsening food, income, and housing insecurity for many PWUD. By contrast, potent illicit drugs remained easily accessible in open-air drug markets. Conclusions. The pandemic exacerbated health risks for PWUD but also offered profound glimpses of beneficial structural changes. Efforts are needed in Tijuana and elsewhere to institutionalize positive pandemic-related shifts and ameliorate novel harms for PWUD. (Am J Public Health. 2022;112(S2):S199-S202. https://doi.org/10.2105/AJPH.2022.306796).