DETECTION OF SARS-COV-2 IN A SQUIRREL MONKEY (SAIMIRI SCIUREUS): A ONE HEALTH INVESTIGATION AND RESPONSE.

Through collaborative efforts, One Health partners have responded to outbreaks of COVID-19 among animals, including those in human care at zoos. Zoos have been faced with numerous challenges, including the susceptibility of many mammalian species, and therefore the need to heighten biosecurity measures rapidly. Robust One Health collaborations already exist in Arizona to address endemic and emerging zoonoses, but these have rarely included zoos. The pandemic shed light on this, and Arizona subsequently expanded its SARS-CoV-2 surveillance efforts to include zoo animals. Testing and epidemiologic support was provided to expedite the detection of and response to zoonotic SARS-CoV-2 infection in zoo animals, as well as to understand possible transmission events. Resulting from this program, SARS-CoV-2 was detected from a rectal swab collected from an 8-yr-old squirrel monkey (Saimiri sciureus) from a zoo in Southern Arizona. The animal had rapidly become ill with nonrespiratory symptoms and died in July 2022. Genomic sequencing from the swab revealed mutations consistent with the Omicron (BA.2) lineage. An epidemiologic investigation identified an animal caretaker in close proximity to the affected squirrel monkey who tested positive for COVID-19 the same day the squirrel monkey died. Critical One Health partners provided support to the zoo through engagement of local, state, and federal agencies. Necropsy and pathologic evaluation showed significant necrotizing colitis; the overall clinical and histopathological findings did not implicate SARS-CoV-2 infection alone as a causal or contributing factor in the squirrel monkey's illness and death. This report documents the first identification of SARS-CoV-2 in a squirrel monkey and highlights a successful and timely One Health investigation conducted through multisectoral collaboration.

Impact of the endovascular revolution on vascular training through analysis of national data case reports.

BACKGROUND: In the last couple of decades, there has been a shift in use of endovascular procedures in vascular surgery. We aim to examine the impact of this endovascular shift on vascular trainees, determine whether the surgical experiences of trainees in the integrated residency and fellowship program changed over time, and identify differences between the two training paradigms. METHODS: Data were extracted from the Accreditation Council for Graduate Medical Education National Data Case Logs for the vascular surgery fellowship (1999-2021) and integrated residency (2012-2021) programs. Every procedure was categorized as open or endovascular, then designated into the following subcategories: thoracic aneurysm repairs, cerebrovascular, abdominal aneurysm repairs, venous, vascular access, peripheral arterial disease, visceral, or miscellaneous. We compared the prevalence of open and endovascular cases in the fellowship and integrated residency using data from overlapping years (2012-2021). In addition, we compared the mean number of cases per trainee per year within designated time intervals. The vascular surgery fellowship was grouped into three intervals: 1999 to 2006, 2006 to 2013, and 2013 to 2021; the integrated vascular surgery residency was grouped into two intervals: 2012 to 2017 and 2017 to 2021. Data were standardized to represent the average number of cases per trainee per year. RESULTS: Within the fellowship, we found a 362.37% increase in endovascular procedures (mean, 56.80 ± 32.57 vs 262.63 ± 9.91; P < .001), although there was only a 32.47% increase in open procedures (220.19 ± 4.55 vs 291.68 ± 8.20) between the first and last time intervals. There was a decrease in abdominal aneurysm repair (24.46 ± 7.30 vs 13.85 ± 0.58; P < .001) and visceral (6.41 ± 0.44 vs 5.80 ± 0.42; P = .039) open procedures. For the integrated residency, there was an increase in open procedures by 8.52% (352.18 ± 8.23 vs 382.20 ± 5.84; P < .001). Residents had greater total, open, and endovascular procedures per year than fellows (all P < .001). Chief residents had approximately one-half as many cases as vascular fellows per year. Fellows performed more open abdominal aneurysm repair (14.04 ± 0.80 vs 12.40 ± 1.32; P = .007) and visceral (5.83 ± 0.41 vs 4.88 ± 0.46; P > .001) procedures than residents. Overall, 52% to 53% of cases performed by trainees per year were open procedures in both the fellowship and integrated residency (288.56 ± 12.10 vs 261.27 ± 10.13, 365.52 ± 17.23 vs 319.58 ± 6.62; both P < .001). Within the subcategories, only cerebrovascular, vascular access, and miscellaneous had more open procedures performed per trainee. CONCLUSIONS: Vascular surgery training has incorporated new endovascular techniques and technologies while maintaining operative training in open procedures. Despite changes in vascular surgery training, trainees are still performing more open procedures than endovascular procedures per year. However, there are evolving deficits in specific types of procedures.

Predictive Dispatch of Volunteer First Responders: Algorithm Development and Validation.

BACKGROUND: Smartphone-based emergency response apps are increasingly being used to identify and dispatch volunteer first responders (VFRs) to medical emergencies to provide faster first aid, which is associated with better prognoses. Volunteers' availability and willingness to respond are uncertain, leading in recent studies to response rates of 17% to 47%. Dispatch algorithms that select volunteers based on their estimated time of arrival (ETA) without considering the likelihood of response may be suboptimal due to a large percentage of alerts wasted on VFRs with shorter ETA but a low likelihood of response, resulting in delays until a volunteer who will actually respond can be dispatched. OBJECTIVE: This study aims to improve the decision-making process of human emergency medical services dispatchers and autonomous dispatch algorithms by presenting a novel approach for predicting whether a VFR will respond to or ignore a given alert. METHODS: We developed and compared 4 analytical models to predict VFRs' response behaviors based on emergency event characteristics, volunteers' demographic data and previous experience, and condition-specific parameters. We tested these 4 models using 4 different algorithms applied on actual demographic and response data from a 12-month study of 112 VFRs who received 993 alerts to respond to 188 opioid overdose emergencies. Model 4 used an additional dynamically updated synthetic dichotomous variable, frequent responder, which reflects the responder's previous behavior. RESULTS: The highest accuracy (260/329, 79.1%) of prediction that a VFR will ignore an alert was achieved by 2 models that used events data, VFRs' demographic data, and their previous response experience, with slightly better overall accuracy (248/329, 75.4%) for model 4, which used the frequent responder indicator. Another model that used events data and VFRs' previous experience but did not use demographic data provided a high-accuracy prediction (277/329, 84.2%) of ignored alerts but a low-accuracy prediction (153/329, 46.5%) of responded alerts. The accuracy of the model that used events data only was unacceptably low. The J48 decision tree algorithm provided the best accuracy. CONCLUSIONS: VFR dispatch has evolved in the last decades, thanks to technological advances and a better understanding of VFR management. The dispatch of substitute responders is a common approach in VFR systems. Predicting the response behavior of candidate responders in advance of dispatch can allow any VFR system to choose the best possible response candidates based not only on ETA but also on the probability of actual response. The integration of the probability to respond into the dispatch algorithm constitutes a new generation of individual dispatch, making this one of the first studies to harness the power of predictive analytics for VFR dispatch. Our findings can help VFR network administrators in their continual efforts to improve the response times of their networks and to save lives.

A Note on Preexposure Prophylaxis Preferences Among Women Who Inject Drugs.

ABSTRACT: We informed women who inject drugs about different preexposure prophylaxis (PrEP) formulations; they then ranked their preferences. Daily oral PrEP was most preferred, followed by injectable PrEP and vaginal rings/gels, especially among women of color. Multiple PrEP options should be discussed with women who inject drugs to increase uptake.

Sex Work Venue Disorder and HIV/STI Risk Among Female Sex Workers in Two México-US Border Cities: A Latent Class Analysis.

Research increasingly recognizes the importance of social and built environments in shaping health, including risks for and outcomes related to HIV and sexually transmitted infections (STI), but research on sex work venues is limited. We use latent class analysis to identify patterns of sex work venue characteristics and factors associated with class membership in two México-US border cities. Among 603 female sex workers (FSW), three classes of sex work venues were identified: low, medium, and high disorder venues, characterized by level of violence, policing and drug activity. In multivariable analysis, risk exposures and outcomes varied by class, suggesting the need for place-based interventions that are tailored to specific venue profiles and that promote FSW health and safety in the workplace.

Long-Acting Injectable Human Immunodeficiency Virus Pre-Exposure Prophylaxis Preferred Over Other Modalities Among People Who Inject Drugs: Findings from a Qualitative Study in California.

People who inject drugs (PWID) have extraordinarily low uptake of human immunodeficiency virus (HIV) pre-exposure prophylaxis (PrEP) despite high levels of need. Long-acting PrEP modalities hold promise for HIV prevention among PWID, but product preferences remain poorly understood. From September to November 2021, we conducted qualitative interviews with 28 HIV-negative, adult (≥18 years) PWID in San Diego County, CA, to explore their perspectives on daily oral PrEP pills and long-acting PrEP modalities (i.e., injections, implants, intravaginal rings, and broadly neutralizing antibodies), which we explained using standard scripts. Thematic analysis identified variations in PrEP modality interest and acceptability. We identified three key factors across the 28 interviews that appeared to influence PrEP modality preferences: perceived convenience of use, invasiveness, and familiarity (based on past experience). Overall, most participants preferred injectable PrEP over other modalities because they viewed injectable medications as convenient, noninvasive, and familiar. While injectable PrEP was recently approved for use in the United States and was most the acceptable PrEP modality in this sample, our findings suggest that intervention and implementation research is urgently needed to improve our understanding of strategies that could support access, uptake, and sustained adherence to longer-acting PrEP for PWID.

Impact of reduced restrictions on buprenorphine prescribing during COVID-19 among patients in a community-based treatment program.

Background: Medications such as buprenorphine are considered the gold standard for the treatment of opioid use disorders. This study aimed to determine whether less restrictive buprenorphine prescribing practices during the COVID-19 pandemic impacted retention in and adherence to buprenorphine among patients accessing treatment from 2018-2020 at a community-based syringe services program. Methods: In this retrospective cohort study, we compared retention in treatment before and during the COVID-19 pandemic. Then, with relaxed restrictions acting as the intervention in a natural experiment, we conducted a sub-analysis of "continuity participants" who accessed treatment services both before and during the COVID-19 period. Records of 418 historical control patients treated with buprenorphine before COVID-19 were compared to 88 patients enrolled during COVID-19 (n=43 remote telemedicine and n=45 remote provider with patient on-site). Cox proportional hazards regressions were used to assess risk factors for treatment discontinuation. The sub-analysis used proportion of days covered (PDC) differences before and during COVID-19 (n=164) for a paired analysis in a nonparametric bootstrap test. Results: The risk of discontinuation was 71% lower in those accessing remote telemedicine during COVID-19 (HR=0.29; CI: 0.18, 0.47) and 51% lower in those accessing their remote provider onsite during COVID-19 (HR=0.49; CI:0.31, 0.77), compared to the historical control group. The average PDC did not significantly differ before and during COVID-19 (difference=2.4%; CI:-0.6%, 5.3%). Conclusions: The risk of discontinuing treatment was lower in both COVID-19 treatment groups compared to historical controls. Less restrictive buprenorphine prescribing guidelines during COVID-19 led to improved retention in care over 6-months.

Naloxone protection, social support, network characteristics, and overdose experiences among a cohort of people who use illicit opioids in New York City.

BACKGROUND: Despite increased availability of take-home naloxone, many people who use opioids do so in unprotected contexts, with no other person who might administer naloxone present, increasing the likelihood that an overdose will result in death. Thus, there is a social nature to being "protected" from overdose mortality, which highlights the importance of identifying background factors that promote access to protective social networks among people who use opioids. METHODS: We used respondent-driven sampling to recruit adults residing in New York City who reported recent (past 3-day) nonmedical opioid use (n = 575). Participants completed a baseline assessment that included past 30-day measures of substance use, overdose experiences, and number of "protected" opioid use events, defined as involving naloxone and the presence of another person who could administer it, as well as measures of network characteristics and social support. We used modified Poisson regression with robust variance to estimate unadjusted and adjusted prevalence ratios (PRs) and 95% confidence intervals (CIs). RESULTS: 66% of participants had ever been trained to administer naloxone, 18% had used it in the past three months, and 32% had experienced a recent overdose (past 30 days). During recent opioid use events, 64% reported never having naloxone and a person to administer present. This was more common among those: aged ≥ 50 years (PR: 1.18 (CI 1.03, 1.34); who identified as non-Hispanic Black (PR: 1.27 (CI 1.05, 1.53); experienced higher levels of stigma consciousness (PR: 1.13 (CI 1.00, 1.28); and with small social networks (< 5 persons) (APR: 1.14 (CI 0.98, 1.31). Having a recent overdose experience was associated with severe opioid use disorder (PR: 2.45 (CI 1.49, 4.04), suicidality (PR: 1.72 (CI 1.19, 2.49), depression (PR: 1.54 (CI 1.20, 1.98) and positive urinalysis result for benzodiazepines (PR: 1.56 (CI 1.23, 1.96), but not with network size. CONCLUSIONS: Results show considerable gaps in naloxone protection among people who use opioids, with more vulnerable and historically disadvantaged subpopulations less likely to be protected. Larger social networks of people who use opioids may be an important resource to curtail overdose mortality, but more effort is needed to harness the protective aspects of social networks.

Who Can I Ask? Who Would I Tell? An Egocentric Network Analysis Among a Sample of Women At-Risk to Explore Anticipated Advice Seeking and Disclosure Around Pre-exposure Prophylaxis (PrEP).

Pre-Exposure Prophylaxis (PrEP) health campaigns invite women to talk with their provider, partner, and peers about PrEP, though they do not offer specific guidance about who and how to engage. This study uses egocentric network methods in a sample of women at risk for HIV to understand what characteristics of women (egos), their networks, and network members (alters) were associated with anticipated PrEP advice-seeking and anticipated PrEP disclosure. Multivariable generalized linear mixed models revealed that women often consider close, supportive, and trusted network members as PrEP discussants while ego-level, network-level, and cross-level interactions depict the complexity of anticipated network activation. Findings highlight the importance of considering women at risk for HIV in a broader social context. Anticipated advice-seeking and disclosure related to PrEP were associated but distinct forms of network activation, which highlights the need to develop specific recommendations about who and how women should engage with their networks around PrEP.

Multiple Victimizations and Overdose Among Women With a History of Illicit Drug Use.

The experiences of violence and overdose are highly prevalent among women who use illicit drugs. This study sought to ascertain whether multiple victimizations during adulthood increase the frequency of women's overdose. The sample comprised 218 women recruited at Philadelphia harm reduction sites during 2016-2017. Victimization was assessed as exposure to 16 types of adulthood violence. Three measures were constructed for multiple victimizations: continuous and categorical polyvictimization, and predominant violence domain. Negative binomial regression estimated the incidence rate ratio (IRR) of lifetime overdoses from multiple victimizations. Lifetime history of opioid use (88.6%) and drug injection (79.5%) were common. Among overdose survivors (68.5%), the median of lifetime overdoses was 3. The majority of participants (58.7%) were victims of predominantly sexual violence, 26.1% experienced predominantly physical abuse/assault, and 3.7% were victims of predominantly verbal aggression/coercive control. Participants reported a mean of seven violence types; the higher-score category of polyvictimization (9-16 violence types) comprised 41.7% of the total sample. In multivariable models, one-unit increase in continuous polyvictimization was associated with 4% higher overdose rates (IRR: 1.04, 95% confidence interval [CI]: [1.00, 1.08]). Compared to women who were not victimized (11.5%), those in the higher-score category of polyvictimization (IRR: 2.01; 95% CI: [1.06, 3.80]) and exposed to predominantly sexual violence (IRR: 2.10, 95% CI: [1.13, 3.91]) were expected to have higher overdose rates. Polyvictimization and sexual violence amplified the risk of repeated overdose among drug-involved women. Female overdose survivors need to be screened for exposure to multiple forms of violence, especially sexual violence. Findings underscore the need to scale-up victimization support and overdose prevention services for disenfranchised women.

Tina's ParTy line: Polysubstance use patterns in sexual minority men living with HIV who use methamphetamine.

INTRODUCTION: This cross-sectional study examined the associations of demographic, structural and psychological factors with distinct typologies of polysubstance use in sexual minority men (SMM) living with HIV who use methamphetamine. METHODS: In total, 161 SMM living with HIV who reported methamphetamine use in the past 3 months were recruited in San Francisco from 2013 to 2017 for a randomised controlled trial. A latent class analysis was conducted by leveraging baseline measures of self-reported use of 15 substances in the past 3 months as well as validated screening measures of hazardous alcohol and cannabis use. Correlates of latent class membership were examined using a three-step categorical latent variable logistic regression. RESULTS: Four typologies of substance use were identified: (i) methamphetamine use only (43%); (ii) methamphetamine and crack-cocaine use (22%); (iii) party and play use-methamphetamine, gamma-hydroxybutyrate and amyl nitrites (i.e. poppers) with erectile dysfunction drugs (31%); and (iv) high polysubstance use (4%). SMM of colour and those with a history of incarceration were more commonly classified as engaging in methamphetamine and crack-cocaine use compared to party and play use. Men with higher sexual compulsivity scores were more commonly classified as engaging in party and play use and polysubstance use. DISCUSSION AND CONCLUSIONS: There is substantial heterogeneity in polysubstance use patterns among SMM living with HIV who use methamphetamine. This will inform the development of tailored substance use interventions addressing the unique needs of SMM of colour and targeting sexual compulsivity as a prominent comorbidity for some men.

Limited Risk Compensation Among Women Who Inject Drugs: Results From the Project Sexual Health Equity Preexposure Prophylaxis Demonstration Study in Philadelphia.

ABSTRACT: The impact of preexposure prophylaxis uptake on sexual and injection-related behaviors among women who inject drugs is poorly understood. Over 24 weeks, preexposure prophylaxis uptake among women who inject drugs was associated with increased sharing of injection equipment but not syringes and no changes in condomless sex, providing limited evidence of risk compensation in this vulnerable population.

Wearable biosensors have the potential to monitor physiological changes associated with opioid overdose among people who use drugs: A proof-of-concept study in a real-world setting.

INTRODUCTION: Wearable biosensors have the potential to monitor physiological change associated with opioid overdose among people who use drugs. METHODS: We enrolled 16 individuals who reported ≥ 4 daily opioid use events within the previous 30 day. Each was assigned a wearable biosensor that measured respiratory rate (RR) and actigraphy every 15 s for 5 days and also completed a daily interview assessing drug use. We describe the volume of RR data collected, how it varied by participant characteristics and drug use over time using repeated measures one-way ANOVA, episodes of acute respiratory depression (≤5 breaths/minute), and self-reported overdose experiences. RESULTS: We captured 1626.4 h of RR data, an average of 21.7 daily hours/participant over follow-up. Individuals with longer injection careers and those engaging in polydrug use captured significantly fewer total hours of respiratory data over follow-up compared to those with shorter injections careers (94.7 vs. 119.9 h, p = 0.04) and injecting fentanyl exclusively (98.7 vs. 119.5 h, p = 0.008), respectively. There were 385 drug use events reported over follow-up. There were no episodes of acute respiratory depression which corresponded with participant reports of overdose experiences. DISCUSSION: Our preliminary findings suggest that using a wearable biosensor to monitor physiological changes associated with opioid use was feasible. However, more sensitive biosensors that facilitate triangulation of multiple physiological data points and larger studies of longer duration are needed.

Willingness to use a wearable device capable of detecting and reversing overdose among people who use opioids in Philadelphia.

BACKGROUND: The incidence of opioid-related overdose deaths has been rising for 30 years and has been further exacerbated amidst the COVID-19 pandemic. Naloxone can reverse opioid overdose, lower death rates, and enable a transition to medication for opioid use disorder. Though current formulations for community use of naloxone have been shown to be safe and effective public health interventions, they rely on bystander presence. We sought to understand the preferences and minimum necessary conditions for wearing a device capable of sensing and reversing opioid overdose among people who regularly use opioids. METHODS: We conducted a combined cross-sectional survey and semi-structured interview at a respite center, shelter, and syringe exchange drop-in program in Philadelphia, Pennsylvania, USA, during the COVID-19 pandemic in August and September 2020. The primary aim was to explore the proportion of participants who would use a wearable device to detect and reverse overdose. Preferences regarding designs and functionalities were collected via a questionnaire with items having Likert-based response options and a semi-structured interview intended to elicit feedback on prototype designs. Independent variables included demographics, opioid use habits, and previous experience with overdose. RESULTS: A total of 97 adults with an opioid use history of at least 3 months were interviewed. A majority of survey participants (76%) reported a willingness to use a device capable of detecting an overdose and automatically administering a reversal agent upon initial survey. When reflecting on the prototype, most respondents (75.5%) reported that they would wear the device always or most of the time. Respondents indicated discreetness and comfort as important factors that increased their chance of uptake. Respondents suggested that people experiencing homelessness and those with low tolerance for opioids would be in greatest need of the device. CONCLUSIONS: The majority of people sampled with a history of opioid use in an urban setting were interested in having access to a device capable of detecting and reversing an opioid overdose. Participants emphasized privacy and comfort as the most important factors influencing their willingness to use such a device. TRIAL REGISTRATION: NCT04530591.

Overdose response among trained and untrained women with a history of illicit drug use: a mixed-methods examination.

Little is known about differences in bystander behavior among people who use drugs, trained and untrained in opioid overdose prevention. We examined three types of recommended overdose response - a 911 call, rescue breathing/CPR, and naloxone administration-among Philadelphia-based, predominantly street-involved women with a history of illicit drug use. The study utilized a convergent mixed methods approach integrating data from 186 quantitative survey responses and 38 semi-structured qualitative interviews. Quantitative findings revealed that compared to untrained women, trained women were more likely to administer naloxone (32.9% vs. 5.2%) and use two recommended responses (20.0% vs. 9.5%). No significant differences were found between the two groups in calling 911 or using rescue breathing/CPR. Qualitative findings indicated that barriers to enacting recommended overdose response were either structural or situational and included the avoidance of police, inability to carry naloxone or phone due to unstable housing, and perceived lack of safety on the streets and when interacting with strangers. Our study demonstrated that overdose training improved the frequency of naloxone administration among this sample of predominantly street-involved women. Future efforts need to focus on avoiding intrusive policing, scaling-up naloxone refill sites, and providing secondary naloxone distribution via drug user networks.

Differential impacts of COVID-19 across racial-ethnic identities in persons with opioid use disorder.

OBJECTIVE: The COVID-19 pandemic has exacerbated health disparities, particularly among at-risk people with opioid use disorder (OUD). We sought to characterize the direct and indirect impacts of COVID-19 on this group to understand how the pandemic has affected this group, this group's public health response to COVID-19, and whether there were differences by race/ethnicity. METHODS: This study recruited its sample from a drug treatment setting in the northeast region of the United States. We surveyed 110 individuals on methadone as treatment for OUD and assessed COVID-19-related impacts on their health behaviors and other indices of social, physical, and mental well-being, including sexual health behaviors, substance use, mental health status, health care access, income, and employment. RESULTS: Our findings highlight overall increases in depression, anxiety, loneliness, and frustration among the sample of people with OUD; the study also observed decreases in financial stability. Significant differences between groups indicated a greater financial burden among racial-ethnic minorities; this subgroup also reported greater direct adverse effects of COVID-19, including being more concerned about contracting COVID-19, not being able to get a COVID-19 test, and knowing someone who had died from COVID-19. A greater proportion of Whites indicated increases in alcohol consumption and non-prescription drug use than did racial-ethnic minorities. CONCLUSIONS: Treatment providers must be vigilant in managing direct and indirect outcomes of COVID-19 among people with OUD. Findings highlight the need to develop culturally competent, differentiated interventions in partnership with community-based organizations to meet the unique challenges that the COVID-19 pandemic presents for people in treatment for OUD.

The Influence of PrEP-Related Stigma and Social Support on PrEP-Use Disclosure among Women Who Inject Drugs and Social Network Members.

Pre-exposure prophylaxis (PrEP) is a promising but underutilized HIV prevention strategy for Women who Inject Drugs (WWID). Stigma and disclosure concerns have been key barriers to PrEP use among women in PrEP efficacy trials. Social support has been found to buffer against some PrEP stigma, though these factors have been largely unexplored among WWID. Investigating how WWID disclose PrEP use is important given evidence that disclosure is associated with higher adherence. We aimed to identify the impact of stigma and support on PrEP disclosure within social networks of WWID participating in a PrEP demonstration project in Philadelphia, PA, USA. PrEP-using WWID ≥ 18 years completed social network surveys. Generalized estimating equations were used to account for the correlation of network structure. Thirty-nine WWID (i.e. egos) named an average of 9.5 ± 3.3 network members (i.e. alters), for a total sample of 371 unique relationships. Egos disclosed their PrEP use to an average of 4.0 alters (SD = 2.8). Related to PrEP stigma, participants had 0.4 times decreased odds of PrEP disclosure with alters who would disapprove of them taking PrEP (95% CI: 0.1-0.9). Related to support, participants had 2.5 times higher odds of disclosure among peers who could provide PrEP advice (95% CI: 1.0-6.0). Interventions that increase social support and decrease stigma are pivotal for increasing PrEP use disclosure among WWID.

Decision-making by laypersons equipped with an emergency response smartphone app for opioid overdose.

BACKGROUND: Targeted naloxone distribution to potential lay responders increases the timeliness of overdose response and reduces mortality. Little is known, however, about the patterns of decision-making among overdose lay responders. This study explored heuristic decision-making among laypersons equipped with an emergency response smartphone app. METHODS: UnityPhilly, a smartphone app that connects lay responders equipped with naloxone to overdose victims, was piloted in Philadelphia from March 2019 to February 2020. Participants used the app to signal overdose alerts to peer app users and emergency medical services, or respond to alerts by arriving at overdose emergency sites. This study utilised in-depth interviews, background information, and app use data from a sample of 18 participants with varying histories of opioid use and levels of app use activity. RESULTS: The sample included 8 people who used opioids non-medically in the past 30 days and 10 people reporting no opioid misuse. Three prevailing, not mutually exclusive, heuristics were identified. The heuristic of unconditional signalling ("Always signal for help or backup") was used by 7 people who valued external assistance and used the app as a replacement for a 911 call; this group had the highest number of signalled alerts and on-scene appearances. Nine people, who expressed confidence in their ability to address an overdose themselves, followed a heuristic of conditional signalling ("Rescue, but only signal if necessary"); these participants had the highest frequency of prior naloxone administrations. Eleven participants used the heuristic of conditional responding ("Assess if I can make a difference"), addressing an alert if they carried naloxone, were nearby, or received a signal before dark hours. CONCLUSION: The deployment of specific heuristics was influenced by prior naloxone use and situational factors. Success of overdose prevention interventions assisted by digital technologies may depend on the involvement of people with diverse overdose rescue backgrounds.

Validation of the Opioid Overdose Risk Behavior Scale, version 2 (ORBS-2).

OBJECTIVE: To examine the factor structure of a revised and expanded opioid overdose risk behavior scale and assess its associations with known overdose indicators and other clinical constructs. BACKGROUND: Opioid-related overdose remains high in the U.S. We lack strong instrumentation for assessing behavioral risk factors. We revised and expanded the opioid overdose risk behavior scale (ORBS-1) for use among a broader range of people who use opioids. SETTING & SAMPLING FRAME: Using respondent-driven sampling we recruited adults (18+) reporting current unprescribed opioid use and New York City residence. METHOD: Participants (N = 575) completed the ORBS-1, ORBS-2, and a variety of clinical measures and then completed the ORBS-2 and overdose risk outcomes across monthly follow-up assessments over a 13-month period. RESULTS: Principal components analysis was used to identify six ORBS-2 subscales, Prescription Opioid Misuse, Risky Non-Injection Use, Injection Drug Use, Concurrent Opioid and Benzodiazepine Use, Concurrent Opioid and Alcohol Use, and Multiple-Drug Polysubstance Use. All subscales showed moderate non-parametric correlations with the ORBS-1 and with corresponding clinical constructs. Five of the subscales were significantly (p < .01) positively associated with self-reported non-fatal overdose. Of note, the Risky Non-Injection Use subscale was the most strongly associated with past-month overdose indicators. CONCLUSIONS: Psychometrics for the opioid overdose risk behavior subscales identified suggest the ongoing utility of risk behavioral instrumentation for epidemiological research and clinical practice focused on risk communication and minimization. Use of the entire ORBS-2 measure can provide insight into the proximal/behavioral factors of greatest concern to reduce overdose mortality.