Stefan completed his certification in Community Medicine as a Fellow of the Royal College of Physicians and Surgeons of Canada and Family medicine with the Canadian Council of Family Physicians. Stefan has also been involved in HIV epidemiology, prevention, and implementation research focused on the epidemiology, human rights contexts, and effective interventions for gay men and other men who have sex with men, transgender women, and female sex workers across Western and Central, and Southern Africa and parts of Asia with support from USAID, CDC, NIH, amfAR, and the Global Fund.