I have been working in the field of HIV, viral hepatitis and substance use for nearly 20 years. I am currently working on issues related to opioid use disorders, medication for opioid use disorder, and the integration of HIV prevention and treatment with medication assisted treatment for opiate use disorders. I am exploring service delivery models for these integrated services and how to increase engagement and retention in medication for opioid use disorder. I also study the uptake of pre-exposure prophylaxis and HIV behavioral surveillance among key populations: men who have sex with men, people who inject drugs, heterosexuals at high risk for HIV, and transgender women.