1. Brown University School of Public Health, Providence, RI, USA
2. The Fenway Institute, Fenway Health, Boston, MA, USA
3. Departments of Behavioral and Social Health Sciences and Epidemiology, Brown University School of Public Health, Providence, RI, USA
4. Department of Biobehavioral Health, Penn State University, Middletown, PA, USA
5. OLB Research Institute, Online Buddies, Inc., Cambridge, MA, USA
6. Division of Infectious Disease, Department of Medicine, Harvard Medical School/Beth Israel Deaconess Medical Center, Boston, MA, USA
7. Center for Alcohol and Addiction Studies, School of Public Health, Brown University, Providence, RI, USA
8. Department of Psychiatry and Human Behavior, Alpert Medical School, Brown University, Providence, RI, USA