Moallef S, Genberg B, Hayashi K, Mehta S, Kirk G, Choi J, DeBeck K, Kipke M, Moore R, Baum M, Shoptaw S, Gorbach P, Mustanski B, Javanbakht M, Siminski S, Milloy MJ Day-to-day impact of COVID-19 and other factors associated with risk of nonfatal overdose among people who use unregulated drugs in five cities in the United States and Canada Drug Alcohol Depend PubMed