Courtney A McKnight
Courtney A McKnight
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Clinical Associate Professor of Epidemiology
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Professional overview
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Dr. Courtney McKnight is a Principal Investigator specializing in mixed methods research focused on the epidemiology of drug use, opioid overdose, HIV and HCV infection. Dr. McKnight has over 20 years of experience conducting public health research related to drug use, as well as field experience as a harm reduction service provider.
Prior to joining NYU, Dr. McKnight served as the assistant director of research at the Chemical Dependency Institute at the Icahn School of Medicine at Mount Sinai, where she was an investigator and project director on numerous federally funded research studies, including evaluations of syringe services programs; investigations of the drivers that contribute to disparate rates of HIV and HCV; and interventions to increase access to HIV and HCV testing and care.
Previous to Dr. McKnight’s work in research, she directed a harm reduction program for women who use drugs and volunteered at a syringe services program in New Jersey.
Dr. McKnight received her DrPH from the City University of New York Graduate Center, her Master of Public Health from Hunter College, and her Bachelor of Arts in sociology from Rutgers University. Her dissertation examined the impact of Medicaid coverage of methadone and buprenorphine on treatment access for opioid dependent beneficiaries.
Dr. McKnight’s current research interests include examining the shifting landscape of illicit opioids, including the increasing prevalence of illicitly manufactured fentanyl, and risk environments of people who use drugs.
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Education
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BA, Women's Studies, Rutgers University, New Brunswick, NJMPH, Community Health Education, Hunter College, New York, NYDrPH, The City University of New York, New York, NY
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Areas of research and study
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Behavioral ScienceDrug addictionEpidemiologyHarm reductionHepatitisHIV/AIDSInfectious DiseasesMixed-Methods ResearchOpioidQualitative ResearchSocial epidemiologySubstance Abuse
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Publications
Publications
Factors associated with carrying naloxone among people who inject drugs in New York City.
AbstractKimball, S., Weng, C. A., McKnight, C. A., & Des Jarlais, D. (n.d.).Publication year
2023Abstract~Fentanyl in NYC
McKnight, C. A. (n.d.).Fentanyl Is Fueling an Unprecedented Rise in Overdose Deaths.
McKnight, C. A. (n.d.).Fentanyl Polysubstance Use Patterns and Their Associations With Hepatitis C Virus, Skin and Soft Tissue Infections, and Non-Fatal Overdose Among People Who Inject Drugs in New York City
AbstractKhezri, M., Kimball, S., Weng, C. A., McKnight, C. A., & Des Jarlais, D. (n.d.).Publication year
2025Journal title
Drug and Alcohol ReviewAbstractIntroduction: Fentanyl's euphoric effects and short half-life may increase infectious disease transmission risks through frequent injecting and syringe sharing. We examined fentanyl polysubstance use (PSU) patterns and associations with hepatitis C virus (HCV), skin and soft tissue infections (SSTI), and non-fatal overdose among people who inject drugs (PWID) in New York City. Methods: We recruited 495 PWID between October 2021 and July 2024. Participants were tested for HCV antibody and underwent urine toxicology screenings using the Premier Biotech 13-panel BioCup. Results: Fentanyl was identified in 83.6% of the sample; however, only 23.0% self-reported recent intentional fentanyl use. The most common fentanyl PSU combinations were fentanyl with methadone (67.9%), opiates (66.9%), cocaine (65.9%), cannabis (45.4%), xylazine (36.7%), heroin (35.5%), benzodiazepines (32.5%) and alcohol (29.3%). Compared to no fentanyl use, intentional fentanyl use was associated with HCV antibody seropositivity (aOR 3.44, 95% CI 1.75, 6.93), SSTIs (aOR 4.75, 1.66, 17.20) and non-fatal overdose (aOR 2.35, 1.15, 5.00). Co-use of fentanyl with opiates (aOR 2.08, 1.16, 3.82), cocaine (aOR 2.71, 1.52, 4.97), heroin (aOR 2.06, 1.11, 3.91), benzodiazepines (aOR 2.91, 1.55, 5.63) and alcohol (aOR 3.27, 1.72, 6.37) were associated with HCV. Co-use of fentanyl with benzodiazepines (aOR 2.08, 1.04, 4.34) and alcohol (aOR 2.57, 1.29, 5.37) were associated with non-fatal overdose. Discussion and Conclusions: In addition to overdose, when combined with other psychoactive substances, fentanyl PSU is associated with a higher prevalence of infectious diseases. This underscores the need for tailored medication dosing for opioid use disorder and expanding access to syringe service programs and medical care for PWID in the fentanyl era.Field Testing the “Avoid the Needle” Intervention for Persons at Risk for Transitioning to Injecting Drug Use in Tallinn, Estonia and New York City, USA
AbstractJarlais, D. C., McKnight, C. A., Weng, C. A., Feelemyer, J., Tross, S., Raag, M., Org, G., Talu, A., & Uuskula, A. (n.d.).Publication year
2023Journal title
AIDS and BehaviorAbstractThis study aimed to field tested the “Avoid the Needle” (AtN) intervention to reduce transitions from non-injecting to injecting drug use in two different epidemiological settings. Respondent driven sampling was used to recruit current non-injecting drug users (NIDUs) in Tallinn, Estonia in 2018-19 and in New York City (NYC) in 2019-20. Both persons who had never injected and persons who had previously injected but not in the last 6 months were eligible; a structured interview was administered, a blood sample collected, and the intervention administered by trained interventionists. We recruited 19 non-injectors from Tallinn and 140 from NYC. Participants in Tallinn were younger and had begun using drugs at earlier ages than participants in NYC. The primary drugs used in Tallinn were amphetamine, fentanyl, and opioid analgesics, while in NYC they were heroin, cocaine, speedball, and fentanyl. Six-month follow-up data were obtained from 95% of participants in Tallinn. The study was interrupted by COVID-19 lockdown in NYC, but follow-up data were obtained from 59% of participants. There were minimal transitions to injecting: 1/18 in Tallinn and 0/83 in NYC. There were significant declines in the frequencies of using readily injectable drugs (fentanyl, amphetamine, heroin, cocaine) from baseline to follow-up in both sites (Cochran-Armitage tests for trend, χ2 = 21.3, p < 0.001 for New York City; and χ2 = 3.9, p = 0.048 for Tallinn). Reducing transitions into injecting is a potentially very important method for reducing HIV transmission and other harms of drug use. Further investigation and implementation of AtN type interventions is warranted.From Long-Term Injecting to Long-Term Non-Injecting Heroin and Cocaine Use : The Persistence of Changed Drug Habits
AbstractJarlais, D. C., Arasteh, K., Feelemyer, J., McKnight, C. A., Barnes, D. M., Tross, S., Perlman, D. C., Campbell, A. N., Cooper, H. L., & Hagan, H. (n.d.).Publication year
2016Journal title
Journal of Substance Abuse TreatmentVolume
71Page(s)
48-53AbstractObjectives Transitioning from injecting to non-injecting routes of drug administration can provide important individual and community health benefits. We assessed characteristics of persons who had ceased injecting while continuing to use heroin and/or cocaine in New York City. Methods We recruited subjects entering Mount Sinai Beth Israel detoxification and methadone maintenance programs between 2011 and 2015. Demographic information, drug use histories, sexual behaviors, and “reverse transitions” from injecting to non-injecting drug use were assessed in structured face-to-face interviews. There were 303 “former injectors,” operationally defined as persons who had injected at some time in their lives, but had not injected in at least the previous 6 months. Serum samples were collected for HIV and HCV testing. Results Former injectors were 81% male, 19% female, 17% White, 43% African-American, and 38% Latino/a, with a mean age of 50 (SD = 9.2), and were currently using heroin and/or cocaine. They had injected drugs for a mean of 14 (SD = 12.2) years before ceasing injection, and a mean of 13 (SD = 12) years had elapsed since their last injection. HIV prevalence among the sample was 13% and HCV prevalence was 66%. The former injectors reported a wide variety of reasons for ceasing injecting. Half of the group appeared to have reached a point where relapse back to injecting was no longer problematic: they had not injected for three or more years, were not deliberately using specific techniques to avoid relapse to injecting, and were not worried about relapsing to injecting. Conclusions Former injectors report very-long term behavior change toward reduced individual and societal harm while continuing to use heroin and cocaine. The behavior change appears to be self-sustaining, with full replacement of an injecting route of drug administration by a non-injecting route of administration. Additional research on the process of long-term cessation of injecting should be conducted within a “combined prevention and care” approach to HIV and HCV infection among persons who use drugs.Gender and age patterns in HSV-2 and HIV infection among non-injecting drug users in New York City
AbstractDes Jarlais, D. C., Arasteh, K., McKnight, C. A., Perlman, D., Hagan, H., Semaan, S., & Friedman, S. R. (n.d.).Publication year
2010Journal title
Sexually Transmitted DiseasesVolume
37Issue
10Page(s)
637-643AbstractObjective: To examine prevalence of and associations between herpes simplex virus type 2 (HSV-2) infection and HIV infection among never-injecting heroin and cocaine drug users (NIDUs) in New York City. METHODS:: Subjects were recruited from patients entering the Beth Israel drug detoxification program. Informed consent was obtained, a structured questionnaire including demographics, drug use history, and sexual risk behavior was administered, and a blood sample was collected for HIV and HSV-2 antibody testing. Results: A total of 1418 subjects who had never (lifetime) injected drugs (NIDUs) were recruited between July 2005 through June 2009. Subjects were primarily male (76%), and black (67%) or Hispanic (25%), reported recent crack cocaine use (74%), and had a mean age of 42 years. Eleven percent of males reported male-with-male sexual (MSM) behavior. The prevalence of both viruses was high: for HSV-2, 61% among the total sample, 50% among non-MSM males, 85% among females, and 72% among MSM; for HIV, 16% among the total sample, 12% among non-MSM males, 20% among females, and 46% among MSM. HSV-2 was associated with HIV (OR = 3.2, 95% CI: 2.3-4.5; PR = 2.7, 95% CI: 2.0-3.7). Analyses by gender and age groups indicated different patterns in mono- and coinfection for the 2 viruses. Discussion: HSV-2 and HIV rates among these NIDUs are comparable with rates in sub-Saharan Africa. Additional prevention programs, tailored to gender and age groups, are urgently needed. New platforms for providing services to NIDUs are also needed.Geographic distribution of risk ("Hotspots") for HIV, HCV, and drug overdose among persons who use drugs in New York City : The importance of local history
AbstractMcKnight, C. A., Des Jarlais, D. C., McKnight, C., Arasteh, K., Feelemyer, J., Ross, Z., & Cooper, H. L. (n.d.).Publication year
2019Journal title
Harm Reduction JournalVolume
16Issue
1AbstractAims: To identify geographic "hotspots" for potential transmission of HIV and HCV and for drug overdose among persons who use heroin and cocaine in New York City and to examine historical continuities in problem drug use hotspots in the city. Methods: A total of 2714 study participants were recruited among persons entering Beth Israel substance use treatment programs. A structured questionnaire was administered and blood samples for HIV and HCV testing were collected. Hotspots for potential virus transmission were defined as ZIP codes with 10+ participants, 2+ persons infected with the virus and engaging in transmission behavior, and 2+ persons not infected and engaging in acquisition behavior. ZIP codes with 3+ persons with previous overdoses were considered potential hotspots for future overdoses. Results: Participants resided in 166/178 (93%) of the ZIP codes in New York City. Injecting drug use was reported in 150/178 (84%) of the ZIP codes. No zip codes were identified for injecting-related HIV transmission, 5 zip codes were identified for sexual HIV transmission, 3 for HCV transmission, and 8 for drug overdose. Many of the ZIP code potential hotspots were in neighborhoods long associated with drug use: Lower Eastside and Harlem in Manhattan, the South Bronx, and Central Brooklyn. Discussion: Heroin and cocaine use requiring treatment were reported from almost all ZIP codes in New York City, indicating needs for widely dispersed harm reduction services. Identified hotspots should be targeted for reducing sexual transmission of HIV, transmission of HCV, and drug overdoses. Some of the hotspots have persisted as problem drug use areas for 40 to over 100 years. Monitoring of drug use patterns in historical hotspot neighborhoods may permit early identification of and response to emerging drug use-related health problems. Persistent historical hotspots for problem drug use present a complex problem for implementing harm reduction services that deserve additional research.Global epidemiology of abortion among female sex workers : a systematic review, meta-analysis, and meta-regression
AbstractKhezri, M., Tavakoli, F., Schwartz, S., Karamouzian, M., Sharifi, H., McKnight, C. A., Jarlais, D. D., Baral, S., & Shokoohi, M. (n.d.).Publication year
2023Journal title
Annals of EpidemiologyVolume
85Page(s)
13-37AbstractPurpose: Despite the evidence of a high rate of unintended pregnancy, there remains limited information about the prevalence and experiences of abortion among female sex workers (FSWs). In response, we aimed to summarize the available evidence on abortion among FSWs. Methods: We searched Medline, Embase, PsycINFO, CINAHL, Scopus, and Web of Science from inception to January 29, 2023. We pooled data from the included studies using random-effects meta-analyses. We also grouped countries for the legality of elective abortion stratified by the United Nations database on abortion laws and policies. Results: We identified 60 eligible studies from 2031 potentially eligible records. The pooled lifetime prevalence of at least one and multiple induced abortions was 37.7% (95% confidence interval, 31.8–43.7) and 21.7% (14.9–29.2), respectively. Among FSWs recruited in countries where elective abortion is illegal, at least one induced abortion prevalence was 35.1% (28.1–42.4), and multiple induced abortion prevalence was 23.1% (12.4–35.9). In countries where elective abortion is legal, at least one induced abortion prevalence was 44.6% (34.8–54.6), and multiple induced abortion prevalence was 19.9% (11.9–29.3). Among FSWs experiencing abortion, self-managed abortion prevalence was estimated at 32.8% (23.6–42.7) overall, 42.8% (37.2–48.5) for countries where elective abortion is illegal, and 15.6% (3.9–32.7) for countries that legally allow elective abortion. Conclusions: Induced abortion is prevalent among FSWs, highlighting the need for interventions to increase access to effective contraception and safe abortion care. While induced abortion prevalence did not significantly differ across the legal grounds for abortion, self-managed abortion prevalence was higher in countries where elective abortion was illegal, highlighting the urgent need for accessible abortion services for FSWs in criminalized settings. Moving forward necessitates implementing and evaluating culturally acceptable models of safe abortion and post-abortion care for FSWs to increase access to the full spectrum of sexual and reproductive health services.Harms associated with injecting in public spaces : a global systematic review and meta-analysis
AbstractKhezri, M., Kimball, S., McKnight, C. A., Rouhani, S., Bunting, A. M., Karamouzian, M., Ompad, D. C., & Des Jarlais, D. (n.d.).Publication year
2025Journal title
International Journal of Drug PolicyVolume
140AbstractBackground: Despite increasing backlash against harm reduction efforts and the need to understand the risk environments encountered by people who inject drugs (PWID), a quantitative systematic review on public injecting and associated health and drug-related outcomes is lacking. We aimed to summarize the global evidence on the prevalence and harms associated with injecting in public spaces. Methods: We searched MEDLINE, Embase, PsycINFO, CINAHL, Scopus, Global Health, and Web of Science from inception to March 21, 2024. We pooled data from included studies using random-effects meta-analyses to quantify the associations between recent (i.e., current or within the last year) public injecting and associated outcomes. Public injecting was defined as injecting in public or semi-public spaces, including streets, parks, and abandoned buildings. Risk of bias was assessed using the Joanna Briggs Institute's critical appraisal tool. Results: Of the 6144 initial records, 84 studies were eligible for inclusion. The pooled prevalence of recent public injecting was 48.85 % (95 % confidence intervals [CI] 43.87, 53.85). Public injecting was associated with increased odds of recent non-fatal overdose (odds ratio [OR] 2.51, 95 % CI 2.01, 3.13), HCV infection (OR 1.55, 95 % CI 1.18, 2.02), recent needle/syringe sharing (OR 2.41, 95 % CI 1.97, 2.94), recent sex work (OR 1.75, 95 % CI 1.03, 2.97), recent incarceration (OR 2.10, 95 % CI 1.78, 2.47), and recent unstable housing/homelessness (OR 4.23, 95 % CI 3.17, 5.65). Public injecting showed a statistically non-significant association with HIV infection (OR 1.41, 95 % CI 0.80, 2.46). Public injecting was also associated with a higher willingness to use supervised injection facilities (OR 2.66, 95 % CI 1.86, 3.80). Conclusion: Public injecting is prevalent among PWID and associated with various adverse drug- and health-related outcomes, highlighting the need for increased access to safe injection spaces. Findings support developing interventions to reduce harms from public injecting, such as addressing structural risks from law enforcement, expanding naloxone programs, and establishing overdose prevention centers. Housing interventions, in particular, could serve as an effective upstream strategy to reduce public injecting and related harms.Harms associated with injecting in public spaces: a global systematic review and meta-analysis
AbstractMcKnight, C. A., Khezri, M., Kimball, S., McKnight, C., Rouhani, S., Bunting, A. M., Karamouzian, M., Ompad, D. C., & Des Jarlais, D. (n.d.).Publication year
2025Journal title
The International journal on drug policyVolume
140Page(s)
104819AbstractDespite increasing backlash against harm reduction efforts and the need to understand the risk environments encountered by people who inject drugs (PWID), a quantitative systematic review on public injecting and associated health and drug-related outcomes is lacking. We aimed to summarize the global evidence on the prevalence and harms associated with injecting in public spaces.Hepatitis C incidence and prevalence among Puerto Rican people who use drugs in New York City
AbstractArasteh, K., Des Jarlais, D. C., Feelemyer, J., & McKnight, C. A. (n.d.).Publication year
2020Journal title
Global Public HealthVolume
15Issue
12Page(s)
1789-1799AbstractBackground: Hepatitis C virus (HCV) infection is associated with substantial morbidity and mortality among people who use drugs (PWUD). Health disparities related to race/ethnicity and immigration status also increase the risk of HCV infection and decrease the probability of linkage to care. Effective, curative treatment is now available for HCV infection and, alongside prevention, may eliminate HCV epidemics. Methods: We examined HCV incidence, prevalence and associated risk factors among 5459 Puerto Rican (both PR-born and U.S.-born) and non-Puerto Rican (only U.S.-born) entrants to Mount Sinai Beth Israel drug treatment programs in New York City, from August 2005 to January 2018, to assess the need for HCV screening, prevention and treatment in this population. Results: HCV incidence and prevalence among Puerto Rican PWUD was significantly greater than the non-Puerto Ricans PWUD. Among people who inject drugs (PWID), there was no difference in injection risk behaviours by ethnicity/birth place. Conclusions: Findings suggest HCV treatment is a necessary component of a strategy to eliminate HCV epidemics among PWUD. Findings also underline the interconnectedness of epidemics across regions, such that to eliminate the HCV epidemic in one location may depend on eliminating the HCV epidemics in other locations.Hepatitis C treatment outcomes among people who inject drugs experiencing unstable versus stable housing : Systematic review and meta-analysis
AbstractKimball, S., Reynoso, M. D., McKnight, C. A., & Des Jarlais, D. (n.d.).Publication year
2024Journal title
PloS oneVolume
19Issue
4Page(s)
e0302471AbstractBACKGROUND: The prevalence of hepatitis C virus (HCV) among people who inject drugs (PWID) is between 50-70%. Prior systematic reviews demonstrated that PWID have similar direct acting antiviral treatment outcomes compared to non-PWID; however, reviews have not examined treatment outcomes by housing status. Given the links between housing and health, identifying gaps in HCV treatment can guide future interventions. METHODS: We conducted a systematic review using Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We searched six databases for articles from 2014 onward. Two reviewers conducted title/abstract screenings, full-text review, and data extraction. We extracted effect measures for treatment initiation, adherence, completion, success, and reinfection by housing status. Studies underwent quality and certainty assessments, and we performed meta-analyses as appropriate. RESULTS: Our search yielded 473 studies, eight of which met inclusion criteria. Only the treatment initiation outcome had sufficient measures for meta-analysis. Using a random-effects model, we found those with unstable housing had 0.40 (0.26, 0.62) times the odds of initiating treatment compared to those with stable housing. Other outcomes were not amenable for meta-analysis due to a limited number of studies or differing outcome definitions. CONCLUSIONS: Among PWID, unstable housing appears to be a barrier to HCV treatment initiation; however, the existing data is limited for treatment initiation and the other outcomes we examined. There is a need for more informative studies to better understand HCV treatment among those with unstable housing. Specifically, future studies should better define housing status beyond a binary, static measure to capture the nuances and complexity of housing and its subsequent impact on HCV treatment. Additionally, researchers should meaningfully consider whether the outcome(s) of interest are being accurately measured for individuals experiencing unstable housing.Hepatitis C virus prevalence and estimated incidence among new injectors during the opioid epidemic in New York City, 2000–2017 : Protective effects of non-injecting drug use
AbstractMcKnight, C. A., Des Jarlais, D. C., Arasteh, K., Feelemyer, J., McKnight, C., Barnes, D. M., Perlman, D. C., Uuskula, A., Cooper, H. L., & Tross, S. (n.d.).Publication year
2018Journal title
Drug and alcohol dependenceVolume
192Page(s)
74-79AbstractObjective: Assess hepatitis C virus (HCV) prevalence and incidence among person who began injecting drugs during the opioid epidemic in New York City (NYC) and identify possible new directions for reducing HCV infection among persons who inject drugs. Methods: 846 persons who began injecting drugs between 2000 and 2017 were recruited from persons entering Mount Sinai Beth Israel substance use treatment programs. A structured interview was administered and HCV antibody testing conducted. Protective effects of non-injecting drug use were examined among persons who “reversed transitioned” to non-injecting drug use and persons who used non-injected heroin in addition to injecting. Results: Participants were 79% male, 41% White, 15% African-American, 40% Latinx, with a mean age of 35. Of those who began injecting in 2000 or later, 97 persons (11%) “reverse transitioned” back to non-injecting drug use. Reverse transitioning was strongly associated with lower HCV seroprevalence (30% versus 47% among those who continued injecting, p < 0.005). Among those who continued injecting, HCV seropositivity was inversely associated with current non-injecting heroin use (AOR = 0.72, 95%CI 0.52-0.99). HCV incidence among persons continuing to inject was estimated as 13/100 person-years. HCV seropositive persons currently injecting cocaine were particularly likely to report behavior likely to transmit HCV. Conclusions: Similar to other locations in the US, NYC is experiencing high rates of HCV infection among persons who have begun injecting since 2000. New interventions that facilitate substitution of non-injecting for injecting drug use and that reduce transmission behavior among HCV seropositives may provide additional methods for reducing HCV transmission.Heroin, Fentanyl, Intentional Fentanyl Use and HIV Transmission in a Community-Recruited Sample of Persons Who Inject Drugs, New York City : 2021–2023
AbstractDes Jarlais, D. C., Weng, C. A., Feelemyer, J., Khezri, M., Reynoso, M. D., Kimball, S., Uuskula, A., & McKnight, C. A. (n.d.).Publication year
2025Journal title
AIDS and BehaviorAbstractWe examined drug use patterns and HIV transmission among persons who inject drugs (PWID) in New York City from 2021 to 2024. Modified respondent-driven sampling was used to recruit PWID from October 2021–February 2024. A structured questionnaire measured demographics, drug use behaviors and overdose experiences (within previous 6 months). Urinalysis was conducted for recent substance use and serum samples were collected for HIV antibody testing. HIV incidence was estimated using a previously published algorithm. We recruited 463 PWID; high percentages of participants reported problematic life circumstances including unstable housing (45%), food insecurity (67%) and drug use problems: 25% reported a recent non-fatal overdose and 55% daily injecting. Fentanyl use was detected in 86% of urinalyses, heroin in 67%, cocaine in 78%, heroin without fentanyl in 1%, and fentanyl and cocaine in 69%. A moderate number of PWID (24%) reported intentional fentanyl use, which was associated with increased food insecurity, unstable housing, injection frequency, cocaine use, and recent non-fatal overdoses and recent receptive syringe sharing. HIV seroprevalence was 6%; there were three likely seroconversions in 1052 total person-years at risk (PYAR) from March 2020 to the times of interviews; estimated HIV incidence rate was 0.19/100 PYAR, 95% CI 0.12–1.67. Despite the increased HIV risks associated with intentional fentanyl use, HIV transmission among PWID has remained low, comparable to pre-fentanyl and pre-COVID-19 levels. Continued monitoring of drug use patterns and increased services for intentional fentanyl use are needed.Heroin, Fentanyl, Intentional Fentanyl Use and HIV Transmission in a Community-Recruited Sample of Persons Who Inject Drugs, New York City: 2021-2023
AbstractMcKnight, C. A., Des Jarlais, D. C., Weng, C. A. A., Feelemyer, J., Khezri, M., Reynoso, M., Kimball, S., Uuskula, A., & McKnight, C. (n.d.).Publication year
2025Journal title
AIDS and behaviorAbstractWe examined drug use patterns and HIV transmission among persons who inject drugs (PWID) in New York City from 2021 to 2024. Modified respondent-driven sampling was used to recruit PWID from October 2021-February 2024. A structured questionnaire measured demographics, drug use behaviors and overdose experiences (within previous 6 months). Urinalysis was conducted for recent substance use and serum samples were collected for HIV antibody testing. HIV incidence was estimated using a previously published algorithm. We recruited 463 PWID; high percentages of participants reported problematic life circumstances including unstable housing (45%), food insecurity (67%) and drug use problems: 25% reported a recent non-fatal overdose and 55% daily injecting. Fentanyl use was detected in 86% of urinalyses, heroin in 67%, cocaine in 78%, heroin without fentanyl in 1%, and fentanyl and cocaine in 69%. A moderate number of PWID (24%) reported intentional fentanyl use, which was associated with increased food insecurity, unstable housing, injection frequency, cocaine use, and recent non-fatal overdoses and recent receptive syringe sharing. HIV seroprevalence was 6%; there were three likely seroconversions in 1052 total person-years at risk (PYAR) from March 2020 to the times of interviews; estimated HIV incidence rate was 0.19/100 PYAR, 95% CI 0.12-1.67. Despite the increased HIV risks associated with intentional fentanyl use, HIV transmission among PWID has remained low, comparable to pre-fentanyl and pre-COVID-19 levels. Continued monitoring of drug use patterns and increased services for intentional fentanyl use are needed.Herpes simplex virus-2 and HIV among noninjecting drug users in New York City
AbstractDes Jarlais, D. C., Hagan, H., Arasteh, K., McKnight, C. A., Perlman, D., & Friedman, S. R. (n.d.).Publication year
2007Journal title
Sexually Transmitted DiseasesVolume
34Issue
11Page(s)
923-927AbstractOBJECTIVE: To examine the relationship between herpes simplex virus 2 (HSV-2) seroprevalence and human immunodeficiency virus (HIV) seroprevalence among noninjecting heroin and cocaine users in New York City. METHODS: Four hundred sixty-two noninjecting cocaine and heroin users were recruited from a drug detoxification program in New York City. Smoking crack cocaine, intranasal use of heroin, and intranasal use of cocaine were the most common types of drug use. A structured interview was administered and a serum sample was collected for HIV and HSV testing. RESULTS: HIV prevalence was 19% (95% CI 15%-22%) and HSV-2 seroprevalence was 60% (95% CI 55%-64%). The adjusted risk ratio for the association between HSV-2 and HIV was 1.9 (95% CI 1.21%-2.98%). The relationship between HSV-2 and HIV was particularly strong among females, among whom 86% were HSV-2 seropositive, 23% were HIV seropositive, and all HIV seropositives were also HSV-2 seropositive. CONCLUSIONS: HSV-2 appears to be an important factor in sexual transmission of HIV among noninjecting cocaine and heroin users in New York City, especially among females. The estimated population attributable risk for HIV infection attributable to HSV-2 infection in this sample was 38%. Programs to manage HSV-2 infection should be developed as part of comprehensive HIV prevention for noninjecting drug users.Heterosexual male and female disparities in HIV infection at the end of an epidemic : HIV infection among persons who inject drugs in New York City, 2001–2005 and 2011–2015
AbstractDes Jarlais, D. C., McKnight, C. A., Feelemyer, J., Arasteh, K., Tross, S., Campbell, A. N., Cooper, H. L., & Perlman, D. C. (n.d.).Publication year
2018Journal title
Drug and alcohol dependenceVolume
185Page(s)
391-397AbstractBackground: We examined whether sex disparities (heterosexual male:female) in HIV infection continue to persist at the “end of the HIV epidemic” among persons who inject drugs (PWID) in New York City (NYC). An “end of the epidemic” was operationally defined as 1) prevalence of untreated HIV infectionHIV infection during limited versus combined HIV prevention programs for IDUs in New York City : The importance of transmission behaviors
AbstractDes Jarlais, D. C., Arasteh, K., McKnight, C. A., Hagan, H., Perlman, D. C., Torian, L. V., Beatice, S., Semaan, S., & Friedman, S. R. (n.d.).Publication year
2010Journal title
Drug and alcohol dependenceVolume
109Issue
1-3Page(s)
154-160AbstractObjectives: As no single HIV prevention program has eliminated HIV transmission, there is growing interest in the effectiveness of " combined" prevention programming. To compare HIV infection among persons injecting in the initial programs environment (IPE) in New York City (self-initiated risk reduction, methadone, education/outreach, and HIV testing) to HIV infection among persons injecting in a combined programs environment (CPE) (above programs plus large-scale syringe exchange). To identify potential behavioral mechanisms through which combined programs are effective. Methods: Subjects were recruited from the Beth Israel drug detoxification program. A risk behavior questionnaire was administered and HIV testing conducted. Subjects who injected only between 1984 and 1994 (IPE) were compared to subjects who injected only between 1995 and 2008 (CPE). Results: 261 IPE subjects and 1153 CPE subjects were recruited. HIV infection was significantly lower among the CPE subjects compared to IPE subjects: prevalence 6% versus 21%, estimated incidence 0.3/100 person-years versus 4/100 person-years (both pHIV risk and prevention among clients of a delivery-based harm reduction service during an HIV outbreak among people who use drugs in northern rural Minnesota, USA
AbstractPalayew, A., Knudtson, K., Purchase, S., Clark, S., Possehl, L., Healy, E., Deutsch, S., McKnight, C. A., Des Jarlais, D., & Glick, S. N. (n.d.).Publication year
2023Journal title
Harm Reduction JournalVolume
20Issue
1AbstractBackground: Since 2019, multiple HIV outbreaks occurred among people who inject drugs (PWID) in Minnesota. Syringe service programs (SSPs) are evidence-based programs that reduce the spread of HIV. We conducted an assessment of characteristics and HIV risk and prevention among clients of a delivery-based SSP near an HIV outbreak in rural, northern Minnesota. Methods: In the fall of 2021, we conducted a cross-sectional survey of clients of a mobile SSP based in Duluth, Minnesota. Survey topics included demographics, drug use, sexual behavior, HIV testing history, and HIV status. We conducted descriptive analyses and used univariate logistic regression to identify correlates of syringe sharing. The analysis was limited to PWID in the last six months. Results: A total of 125 people were surveyed; 77 (62%) were PWID in the last six months. Among these participants, 52% were female and 50% were homeless. Thirty-two percent reported sharing syringes and 45% reported sharing injecting equipment. Approximately one-half (49%) of participants had been tested for HIV in the past year, and none reported being HIV-positive. Individuals reported low condom usage (88% never used), and 23% of participants reported engaging in some form of transactional sex in the last six months. Incarceration in the last year was associated with sharing syringes (odds ratio = 1.4, 95% confidence interval 1.1–1.8). Conclusion: HIV risk was high among PWID receiving services at this SSP. These data highlight a rural SSP that is engaged with people at risk for HIV and needs additional support to expand harm reduction services.HSV-2 co-infection as a driver of HIV transmission among heterosexual non-injecting drug users in New York City
AbstractDes Jarlais, D. C., Arasteh, K., McKnight, C. A., Perlman, D. C., Feelemyer, J., Hagan, H., & Cooper, H. L. (n.d.).Publication year
2014Journal title
PloS oneVolume
9Issue
1AbstractObjective: To examine herpes simplex virus 2 (HSV-2)/HIV co-infection as a contributing factor in the increase in HIV infection among non-injecting heroin and cocaine users in New York City. Methods: Subjects were recruited from the Beth Israel Medical Center drug detoxification and methadone maintenance programs in New York City in 1995-1999 and 2005-2011. All reported current heroin and/or cocaine use and no injection drug use. A structured questionnaire was administered and serum samples collected for HIV and HSV-2 testing. Population-attributable risk percentages (PAR%s) were estimated for associations between HSV-2 and increased susceptibility to and increased transmissibility of HIV among female NIDUs. Results: 785 subjects were recruited from 1995-1999, and 1764 subjects from 2005-2011. HIV prevalence increased from 7% to 13%, with nearly uniform increases among all demographic subgroups. HSV-2/HIV co-infection was common in both time periods, with an average (over the two time periods) of 80% of HIV negative females infected with HSV-2, an average of 43% of HIV negative males infected with HSV-2; an average of 97% of HIV positive females also infected with HSV-2 and an average of 67% of HIV positive males also infected with HSV-2. The increase in HIV prevalence was predominantly an increase in HSV-2/HIV co-infection, with relatively little HIV mono-infection in either time period. The estimated PAR%s indicate that approximately half of HIV acquisition among females was caused by HSV-2 infection and approximately 60% of HIV transmission from females was due to HSV-2 co-infection. Conclusions: The increase in HIV infection among these non-injecting drug users is better considered as an increase in HSV-2/HIV co-infection rather than simply an increase in HIV prevalence. Additional interventions (such as treatment as prevention and suppressing the effects of HSV-2 on HIV transmission) are needed to reduce further HIV transmission from HSV-2/HIV co-infected non-injecting drug users.HSV-2 Infection as a Cause of Female/Male and Racial/Ethnic Disparities in HIV Infection
AbstractDes Jarlais, D. C., Arasteh, K., McKnight, C. A., Perlman, D. C., Cooper, H. L., & Hagan, H. (n.d.).Publication year
2013Journal title
PloS oneVolume
8Issue
6AbstractObjectives:To examine the potential contribution of herpes simplex virus 2 (HSV-2) infection to female/male and racial/ethnic disparities in HIV among non-injecting heroin and cocaine drug users. HSV-2 infection increases susceptibility to HIV infection by a factor of two to three.Methods:Subjects were recruited from entrants to the Beth Israel drug detoxification program in New York City 2005-11. All subjects reported current use of heroin and/or cocaine and no lifetime injection drug use. A structured questionnaire was administered and serum samples collected for HIV and HSV-2 testing. Population-attributable risk percentages (PAR%s) were calculated for associations between HSV-2 infection and increased susceptibility to HIV.Results:1745 subjects were recruited from 2005-11. Overall HIV prevalence was 14%. Females had higher prevalence than males (22% vs. 12%) (pIn New York, fentanyl replaces heroin, without the knowledge of drug addicts.
McKnight, C. A. (n.d.).Incidence and prevalence of hepatitis c virus infection among persons who inject drugs in New York City : 2006-2013
AbstractJordan, A. E., Des Jarlais, D. C., Arasteh, K., McKnight, C. A., Nash, D., & Perlman, D. C. (n.d.).Publication year
2015Journal title
Drug and alcohol dependenceVolume
152Page(s)
194-200AbstractBackground: Hepatitis C virus infection is a source of significant preventable morbidity and mortality among persons who inject drugs (PWID). We sought to assess trends in hepatitis C virus (HCV) infection among PWID from 2006 to 2013 in New York City (NYC). Methods: Annual cross-sectional surveys of PWID entering a large drug abuse treatment program were performed. Risk behavior questionnaires were administered, and HIV and HCV testing were conducted. Comparisons were made with prior prevalence and incidence estimates in 1990-1991 and 2000-2001 reflecting different periods of combined prevention and treatment efforts. Results: HCV prevalence among PWID (N: 1535) was 67% (95% CI: 66-70%) during the study period, and was not significantly different from that observed in 2000-2001. The estimated HCV incidence among new injectors (persons injecting for ≤6 years) during 2006-2013 was 19.5/100 PYO (95% CI: 17-23) and did not differ from that observed in 2000-2001 (18/100 PYO, 95% CI: 14-23/100). Conclusions: Despite the expansion of combined prevention programming between 2000-2001 and 2006-2013, HCV prevalence remained high. Estimated HCV incidence among new injectors also remained high, and not significantly lower than in 2000-2001, indicating that expanded combined prevention efforts are needed to control the HCV epidemic among PWID in NYC.Injection and Heterosexual Risk Behaviors for HIV Infection Among Non-gay Identifying Men Who Have Sex with Men and Women
AbstractArasteh, K., Des Jarlais, D. C., McKnight, C. A., & Feelemyer, J. (n.d.).Publication year
2019Journal title
AIDS and BehaviorVolume
23Issue
12Page(s)
3315-3323AbstractNon-gay identifying men who have sex with men and women (MSMW) are an important subgroup of men who have sex with men (MSM) and have been underrepresented in studies of MSM that only use gay venues to draw their samples. We assessed heterosexual and drug use risks of MSMW who use drugs in a sample of male entrants to the Mount Sinai Beth Israel drug treatment programs from 2005 to 2018. Blood samples were collected and tested for HIV and HSV-2 infections. Among HIV seronegative participants, MSMW had significantly greater odds of sharing used needles with others, and reporting unprotected sex with female casual partners and female commercial sex partners, compared to their counterparts who reported sex with women exclusively (MSWE). Although not recruited from gay venues, MSMW had a significantly higher HIV prevalence than MSWE (23% vs. 10%, p < 0.001). Interventions that are specifically tailored to HIV prevention among MSMW are needed to ameliorate the prevalence of HIV risks and infection.