He started working at the University Hospitals Leuven in 1998 and became Professor of Virology at the K.U. Leuven. Currently, he is associate chief of the department of laboratory medicine, and heads the diagnostic virology laboratory at the University Hospitals Leuven, Belgium. He is also the director of the AIDS reference laboratory and of the national coronavirus and rotavirus reference laboratories. Professor Van Ranst was appointed in 1999 to the Belgian high council for public health. He published over 220 scientific papers in peer reviewed journals and contributed eight chapters to books on molecular evolution and bioinformatics. In 2004 Marc Van Ranst was granted the European Clinical Virology Heine-Medin award of the European Society for Clinical Virology. In 2005, he received a doctor honoris causa degree at the University of Kalmar in Sweden. Marc Van Ranst is the chairman of the editorial board of VacciNewsNet, a social media platform that provides accurate information on vaccines.