Welcome, Dr. Huan Vinh Dong from the David Geffen School of Medicine, University of California Los Angeles (UCLA), USA, to undertake the elective study at the Division of Infectious Diseases, Department of Pediatrics, Faculty of Medicine Siriraj Hospital, Mahidol University, under the supervision of Assoc. Prof. Wanatpreeya Phongsamart starting from April 18th – 29th, 2022.