Courtney A McKnight
Courtney A McKnight
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Clinical Assistant 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
Anti-vaccine attitudes and COVID-19 vaccine status at the end of the U.S. public health emergency
AbstractChoi, J., Feelemyer, J., Choe, K., Lynch, K., McKnight, C., Yang, L. H., Jarlais, D. D., & Chang, V. W. (n.d.).Publication year
2025Journal title
VaccineVolume
55AbstractIntroduction: Despite the end of the federal COVID-19 public health emergency in May 2023, COVID-19 prevention remains a priority. This study investigates how public vaccination attitudes and perceived COVID-19 risks relate to vaccination status, aiming to identify factors associated with COVID-19 vaccination post-emergency. Methods: An online survey was conducted from April to May 2023 among a non-representative, nationally-based sample of MTurk workers. The primary outcome was COVID-19 vaccination status. Variables examined included anti-vaccine attitudes, health status, COVID-19 experiences, and sociodemographic factors. We created a composite measure of anti-vaccine attitudes from 15 items with three levels. Bivariate tests of association and multivariable logistic regression were performed. Results: A final sample of 989 adults were included in this analysis. In our multivariable model, individuals with higher anti-vaccine attitudes were less likely to be vaccinated against COVID-19 compared to those with low anti-vaccine attitudes (OR = 0.10, 95 % CI 0.04, 0.25). Those who identified as LGBQ+ (OR = 2.55, 95 % CI 1.32, 4.94), had chronic conditions (OR = 2.94, 95 % CI 1.43, 6.01) and had felt stigmatized from COVID-19 infections (OR = 3.33, 95 % CI 1.47, 7.58) were more likely to be vaccinated, even after adjusting for anti-vaccine attitudes. News source, perceived risk of contagion by contact, and long COVID-related factors were not significantly associated with vaccination status in the multivariable model. Discussion: Our findings highlight the persistent relationship between anti-vaccine attitudes and vaccination status in the “post-pandemic” era. Beyond vaccine attitudes, sexual orientation, chronic conditions, and stigmatization experiences may influence perceived need for protection. Stigma can sometimes reinforce social norms driving vaccination, but this effect is nuanced, particularly with anti-vaccine attitudes. To promote vaccine uptake, interventions should prioritize community support, counter misinformation, and enhance vaccine literacy. Building trust among vulnerable populations is essential, rather than relying on public health messaging that may reinforce social stigma.Engagement in hepatitis C virus cascade of care and factors associated with testing among people who inject drugs in Iran
AbstractKhezri, M., Tavakoli, F., Mehmandoost, S., Sharafi, H., Zamani, O., Bazrafshani, M. S., Nasiri, N., Mirzaei, H., Moameri, H., Haghdoost, A. A., McKnight, C., Des Jarlais, D., Karamouzian, M., & Sharifi, H. (n.d.).Publication year
2025Journal title
Harm Reduction JournalVolume
22Issue
1AbstractBackground: 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.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., & Des Jarlais, D. (n.d.).Publication year
2025Journal title
Drug and Alcohol ReviewVolume
44Issue
5Page(s)
1543-1555AbstractIntroduction: 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.Harms associated with injecting in public spaces: a global systematic review and meta-analysis
AbstractKhezri, M., Kimball, S., McKnight, C., 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.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., 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.COVID-19 vaccination uptake and determinants of booster vaccination among persons who inject drugs in New York City
AbstractKhezri, M., McKnight, C., Weng, C. A., Kimball, S., & Des Jarlais, D. (n.d.).Publication year
2024Journal title
PloS oneVolume
19Issue
5AbstractBackground 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.Facilitators and barriers to monitoring and evaluation at syringe service programs
AbstractHealy, E., Means, A. R., Knudtson, K., Frank, N., Juarez, A., Prohaska, S., McKnight, C., Des Jarlais, D., Asher, A., & Glick, S. N. (n.d.).Publication year
2024Journal title
Harm Reduction JournalVolume
21Issue
1AbstractBackground: Syringe services programs (SSPs) provide harm reduction supplies and services to people who use drugs and are often required by funders or partners to collect data from program participants. SSPs can use these data during monitoring and evaluation (M&E) to inform programmatic decision making, however little is known about facilitators and barriers to collecting and using data at SSPs. Methods: Using the Consolidated Framework for Implementation Research (CFIR), we conducted 12 key informant interviews with SSP staff to describe the overall landscape of data systems at SSPs, understand facilitators and barriers to data collection and use at SSPs, and generate recommendations for best practices for data collection at SSPs. We used 30 CFIR constructs to develop individual interview guides, guide data analysis, and interpret study findings. Results: Four main themes emerged from our analysis: SSP M&E systems are primarily designed to be responsive to perceived SSP client needs and preferences; SSP staffing capacity influences the likelihood of modifying M&E systems; external funding frequently forces changes to M&E systems; and strong M&E systems are often a necessary precursor for accessing funding. Conclusions: Our findings highlight that SSPs are not resistant to data collection and M&E, but face substantial barriers to implementation, including lack of funding and disjointed data reporting requirements. There is a need to expand M&E-focused funding opportunities, harmonize quantitative indicators collected across funders, and minimize data collection to essential data points for SSPs.Hepatitis C treatment outcomes among people who inject drugs experiencing unstable versus stable housing: Systematic review and meta-analysis
AbstractKimball, S., Reynoso, M., McKnight, C., & Jarlais, D. D. (n.d.).Publication year
2024Journal title
PloS oneVolume
19Issue
4AbstractBackground 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.COVID-19 vaccination and HIV transmission among persons who inject drugs during the first two years of the COVID-19 pandemic in New York City
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
Global epidemiology of abortion among female sex workers: a systematic review, meta-analysis, and meta-regression
HIV 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
Understanding intentionality of fentanyl use and drug overdose risk: Findings from a mixed methods study of people who inject drugs in New York City
Modeling HIV transmission among persons who inject drugs (PWID) at the “End of the HIV Epidemic” and during the COVID-19 pandemic
Recurrent Injecting Drug Use as a Mediator between Psychiatric Disorder and Non-Fatal Overdose
Thick trust, thin trust, social capital, and health outcomes among trans women of color in New York City
Is your syringe services program cost-saving to society? A methodological case study
Hepatitis C incidence and prevalence among Puerto Rican people who use drugs in New York City
Toward the Interpretation of Positive Testing for Fentanyl and Its Analogs in Real Hair Samples: Preliminary Considerations
Alternative kinship structures, resilience and social support among immigrant trans Latinas in the USA
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
Injection and Heterosexual Risk Behaviors for HIV Infection Among Non-gay Identifying Men Who Have Sex with Men and Women
Prescription opiate analgesics, heroin, HIV and HCV among persons who inject drugs in New York City, 2016-2018
Being “hooked up” during a sharp increase in the availability of illicitly manufactured fentanyl: Adaptations of drug using practices among people who use drugs (PWUD) in New York City
Cost-effectiveness of hepatitis C screening and treatment linkage intervention in US methadone maintenance treatment programs