Summary of Proposed Supplement This proposed research undertakes to evaluate the impact of the novel coronavirus pandemic on the parent study’s sample of 576 adult-age people who use unprescribed opioids. Covid-19 infections in NYC hold the potential to impact opioid-related overdose risk behaviors—the parent study’s main outcome—by changing access to naloxone and related health services for people who use drugs. Evaluating the multiple physiological, psychological, and social domains through which the pandemic can impact opioid-related risk is essential both to understanding the unique vulnerabilities of this population during public health crises and to maintaining the empirical integrity of the parent grant’s aims. Specifically, the population of people who use nonprescribed opioids in NYC is subject to disruptions in their access to naloxone, opioid agonist therapies, and syringe service programs, while social distancing is likely to result in greater incidence of socially isolated opioid use, diminishing the opportunity for peers or other bystanders to administer naloxone and/or call 911 in the event of an overdose. The parent study’s participant cohort is currently being followed prospectively using remote, web- and SMS-based survey instruments, which can be modified and expanded to include novel coronavirus measures. This research supplement will utilize this capacity to achieve the following mixed- method aims which parallel the parent aims and guarantee that the parent grant findings are not confounded by the enormous physiological and psychosocial impacts of the pandemic on study participants and their opioid use: a) Examine the impact of the Covid-19 epidemic in NYC on participants’ access to and utilization of the overdose reversal drug, naloxone; b) Evaluate physiological, psychological, and social impacts of the coronavirus epidemic in NYC as potential predictors of opioid-related overdose risk behavior; and c) Analyze participant and treatment/service provider’ perceptions of the processes whereby the coronavirus epidemic has precipitated changes in unprescribed opioid use and related overdose risk. By achieving these aims, this supplementary inquiry will contribute important preliminary understandings of how multiple forms of risk management overlap in the lives of low-income and largely unstably housed people who use opioids. By providing timely data on the unique vulnerabilities of this population during an emerging public health crisis, the study will be strongly positioned to contribute an empirical base to health policy that mitigates both disease transmission and mortality among this at-risk population.