Thomas graduated as MD from Ghent University in 1987 and obtained a degree in Tropical Medicine from the Institute of Tropical Medicine in Antwerp in 1988. After about 10 years working in the field in emergency relief in Africa and HIV/STD research and surveillance in both Belgium and Africa, he went back to school to obtain a Masters in biostatistics from the University of Limburg in 1999.

Following this, he was selected for a 2-year fellowship as Epidemiology Intelligence Service officer at the Centers for Disease Control where he was stationed within the Vaccine Safety Branch of the National Immunization Program.

From 2001 to 2011, he has been employed by GlaxoSmithKline where he was first responsible for the vaccine epidemiology group, for another 5 years in charge of the company’s vaccine safety group and finally in charge of the Health Outcomes Group, which included the Epidemiology, Health Economics and PharmacoEpidemiology teams.
Since leaving GSK in 2011, he has founded P95, a company that provides consultancy and outsourcing services in the field of PharmacoVigilance, Epidemiology and PharmacoEpidemiology.