About

Dr. Courtney A McKnight is a Principal Investigator specializing in mixed methods research focused on the epidemiology of drug use, opioid overdose, HIV, and HCV infection. She has over 20 years of experience conducting public health research related to drug use and has field experience as a harm reduction service provider. Prior to joining NYU, she served as the assistant director of research at the Chemical Dependency Institute at the Icahn School of Medicine at Mount Sinai, where she was involved in federally funded research studies including evaluations of syringe services programs, investigations of drivers contributing to disparities in HIV and HCV rates, and interventions to increase access to testing and care. Her academic background includes a DrPH from the City University of New York Graduate Center, an MPH from Hunter College, and a BA in sociology from Rutgers University. Her research interests encompass the shifting landscape of illicit opioids, including illicitly manufactured fentanyl, and the risk environments of people who use drugs.

Research topics

• Sociology
• Social Science
• Medicine
• Psychiatry
• Anesthesia
• Emergency medicine
• Demography
• Environmental health
• Pharmacology
• Psychology
• Social psychology
• Immunology
• Geography
• Ethnology

Selected publications

• Increasingly Problematic Drug Use and but Very Low HIV Transmission Among Persons who Inject Drugs in New York City: 2021- 2023

  Drug and Alcohol Dependence · 2025-02-01

  articleSenior author
  PublisherDOI

• Engagement in hepatitis C virus cascade of care and factors associated with testing among people who inject drugs in Iran

  Harm Reduction Journal · 2025-04-08

  articleOpen access

  BACKGROUND: Understanding the hepatitis C virus (HCV) cascade of care (CoC) and factors associated with engagement is crucial for designing interventions for achieving HCV elimination. However, data on engagement in the HCV CoC among people who inject drugs (PWID) in the Middle East and North Africa remains limited. We examined the HCV CoC and factors associated with testing among Iranian PWID. METHODS: We recruited PWID in 14 cities using respondent-driven sampling. PWID completed structured interviews capturing measures on socio-demographics, behaviors, and HCV CoC. We examined the self-reported numbers and proportions of individuals who ever tested for HCV, tested positive for HCV antibody, were diagnosed with HCV, initiated HCV treatment, and achieved sustained virologic response (SVR). Multivariable logistic regression models were built to assess factors associated with HCV antibody testing. RESULTS: Of 2308 PWID, 23.1% had ever received an HCV antibody test, 13.9% received the HCV antibody test in the last year, 3.4% had tested positive for HCV antibodies, and 2.5% had received an HCV diagnosis. Of those diagnosed, 54.4% reported initiating treatment, and 31.6% had achieved SVR. HCV antibody testing was significantly associated with having knowledge about HCV transmission through sharing needle/syringe (adjusted odds ratio [aOR] 8.09; 95% confidence intervals [CI] 5.25, 12.48), living with HIV (aOR 4.15; 1.58, 10.92), no previous history of homelessness (aOR 1.89; 1.31, 2.72), history of arrest/incarceration (aOR 1.83; 1.26, 2.64), history of being diagnosed with any mental health problems (aOR 2.88; 1.79, 4.61), history of non-fatal overdose (aOR 1.51; 1.08, 2.10), receiving needle exchange programs in the last 12 months (aOR 6.20; 3.86, 9.93), opioid agonist treatment in the last six months (aOR 2.10; 1.39, 3.18), and having ever received HBV vaccine (aOR 2.31; 1.59, 3.35). CONCLUSIONS: We found a considerably low engagement in HCV CoC among PWID in Iran. Enhancing access to testing services for PWID, especially those with limited awareness of HCV transmission and those encountering structural challenges, is essential as the initial step in the HCV CoC. This improvement is vital for strengthening HCV elimination efforts in Iran.

  PublisherOA PDFDOI

• Heroin, Fentanyl, Intentional Fentanyl Use and HIV Transmission in a Community-Recruited Sample of Persons Who Inject Drugs, New York City: 2021–2023

  AIDS and Behavior · 2025-04-24 · 2 citations

  articleSenior author
  PublisherDOI

• Harms associated with injecting in public spaces: a global systematic review and meta-analysis

  International Journal of Drug Policy · 2025-04-26 · 2 citations

  reviewOpen access
  PublisherOA PDFDOI

• Anti-vaccine attitudes and COVID-19 vaccine status at the end of the U.S. public health emergency

  Vaccine · 2025-03-18

  article
  PublisherDOI

• Mixed Methods Investigation of Xylazine Use Among People who Inject Drugs (PWID) in New York City

  Drug and Alcohol Dependence · 2025-02-01

  article1st authorCorresponding
  PublisherDOI

• Factors Associated With Carrying Naloxone Among People who Inject Drugs in New York City: A Mixed-Methods Analysis

  Drug and Alcohol Dependence · 2025-02-01

  article
  PublisherDOI

• 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

  Drug and Alcohol Review · 2025-06-03 · 2 citations

  articleOpen accessCorresponding

  INTRODUCTION: 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.

  PublisherOA PDFDOI

• Naloxone Carriage Among People Who Inject Drugs in New York City

  Drug and Alcohol Review · 2025-08-18

  article

  INTRODUCTION: Naloxone carriage allows for timely use to reverse opioid-involved overdoses. This study seeks to determine the prevalence of naloxone carriage, as well as associated factors, among people who inject drugs in New York City. METHODS: Using respondent-driven sampling, people who inject drugs across New York City were recruited to complete a cross-sectional survey between 2021 and 2024. Naloxone carriage was defined as self-reporting naloxone carriage 'most of the time' or 'always'. Variables related to demographics, substance use, overdose, treatment history, syringe source and prior naloxone experience were included. Data were analysed using bivariable and multivariable logistic regression. RESULTS: In this sample of 361 participants, 162 (45%) reported naloxone carriage. The majority of participants were male (71%; n = 258) with an average age of 48.48 (SD 10.23). The odds of carrying naloxone were significantly higher among those who experienced recent food insecurity (adjusted odds ratio [aOR] 2.18; 95% confidence interval [CI] 1.34, 3.56), reported fewer years of injection drug use (aOR 1.03; 95% CI 1.01, 1.05), used naloxone to reverse someone else's overdose (aOR 2.54; 95% CI 1.56, 4.14), received syringes from a syringe service program (aOR 3.33; 95% CI 1.61, 7.14), and used test shots as an overdose prevention strategy (aOR 2.55; 95% CI 1.33, 3.56). DISCUSSION AND CONCLUSIONS: While a higher prevalence than other studies, less than half the sample reported naloxone carriage. There are modifiable factors that can increase naloxone carriage at the individual level. However, given the low prevalence of naloxone carriage, there is a need for further intervention, particularly at the systemic level.

  PublisherDOI

• COVID-19 vaccination uptake and determinants of booster vaccination among persons who inject drugs in New York City

  PLoS ONE · 2024-05-14 · 5 citations

  articleOpen access

  BACKGROUND: Persons who inject drugs (PWID) may be unengaged with healthcare services and face an elevated risk of severe morbidity and mortality associated with COVID-19 due to chronic diseases and structural inequities. However, data on COVID-19 vaccine uptake, particularly booster vaccination, among PWID are limited. We examined COVID-19 vaccine uptake and factors associated with booster vaccination among PWID in New York City (NYC). METHODS: We recruited PWID using respondent-driven sampling from October 2021 to November 2023 in a survey that included HIV and SARS-CoV-2 antibodies testing. The questionnaire included demographics, COVID-19 vaccination and attitudes, and drug use behaviors. RESULTS: Of 436 PWID, 80% received at least one COVID-19 vaccine dose. Among individuals who received at least one COVID-19 vaccine dose, 95% were fully vaccinated. After excluding participants recruited before booster authorization for general adults started in NYC, and those who had never received an initial vaccination, 41% reported having received a COVID-19 booster vaccine dose. COVID-19 booster vaccination was significantly associated with having a high school diploma or GED (adjusted odds ratio (aOR) 1.93; 95% confidence interval (CI) 1.09, 3.48), ever received the hepatitis A/B vaccine (aOR 2.23; 95% CI 1.27, 3.96), main drug use other than heroin/speedball, fentanyl and stimulants (aOR 14.4; 95% CI 2.32, 280), number of non-fatal overdoses (aOR 0.35; 95% CI 0.16, 0.70), and mean vaccination attitude score (aOR 0.94; 95% CI 0.89, 0.98). CONCLUSIONS: We found a suboptimal level of COVID-19 booster vaccination among PWID, which was consistent with the rates observed in the general population in NYC and the U.S. Community-based interventions are needed to improve COVID-19 booster vaccination access and uptake among PWID. Attitudes towards vaccination were significant predictors of both primary and booster vaccination uptake. Outreach efforts focusing on improving attitudes towards vaccination and educational programs are essential for reducing hesitancy and increasing booster vaccination uptake among PWID.

  PublisherOA PDFDOI

Recent grants

• Reinvigorating HIV Prevention and Care for People Who Use Drugs: Accelerating Progress and Sustaining Gains in the Midst of Societal Disruption

  NIH · $31.7M · 1998–2028

• Risk Factors for AIDS among persons who inject drugs: HIV transmission during and after the pandemic

  NIH · $26.5M · 1994–2027

Frequent coauthors

• Don C. Des Jarlais

  New York University

  106 shared

• David C. Perlman

  76 shared

• Kamyar Arasteh

  64 shared

• Jonathan Feelemyer

  New York University

  59 shared

• Holly Hagan

  47 shared

• Susan Tross

  New York State Psychiatric Institute

  40 shared

• Hannah L. F. Cooper

  37 shared

• Aimee Campbell

  Riverside Research Institute

  32 shared