His bio on the WHO site:
Johan Giesecke trained as an infectious disease clinician in Stockholm, Sweden during the 1980’s, and from his work with AIDS patients he became interested in the epidemiology of infectious diseases. He received an MSc in epidemiology from London School of Hygiene and Tropical Medicine in 1992, and then worked as a Senior Lecturer at the school for a few years. After this he became State Epidemiologist for Sweden (1995 to 2005) and during a one-year sabbatical 1999-2000 he led the group working on the revision of the International Health Regulations at WHO HQ. From 2005 to 2014 he was the first Chief Scientist of the European Centre for Disease Prevention and Control (ECDC).
Professor Giesecke has written a textbook on infectious disease epidemiology, and now teaches on this subject as a professor emeritus at the Karolinska Institute Medical University in Stockholm.