Herasun Oleksandr Borysovych was born in 1977. In 2000, he graduated from the Medical Faculty of the Danylo Halytsky Lviv State Medical University, specializing in "General Medicine." 2000-2001 - he underwent internship; 2001-2003 - he completed clinical residency at the Department of Infectious Diseases of the Danylo Halytsky Lviv National Medical University. After completing clinical residency, he worked for 2 years as an infectious disease specialist at the Lviv Regional Center for Combating and Preventing HIV/AIDS. Since January 2004, he has been employed as an assistant at the Department of Infectious Diseases of the LNMU. In 2007, he defended his PhD thesis on the topic "Clinical, epidemiological and immunopathogenetic features of HBe-negative HBV-DNA-positive chronic hepatitis B." He participated in international scientific programs on the study of chronic hepatitis and HIV infection. In 2015, he received the title of associate professor. He conducts classes with students and doctors of the Faculty of Postgraduate Education, and delivers lectures on the topics of hepatology and HIV infection.