• Professor Internal Medicine, Leiden University
  
• Member of the Board 'Stichting Biowetenschappen en Maatschappij'
• Royal Netherlands Academy of Arts and Sciences (KNAW), member SPIN-commity
  
• Health Council of the Netherlands,  Infectious diseases and Immunity, advising member  

Additional functions, concluded as of august 2013

• Medicines Evaluation Board, vice chairman
• Scientific Advisory Group, anti-Infectives, European Medicine Agency, London, chairman
• Disciplinary Board The Hague region region, member
• Association for Infectious Diseases, chairman
• Inter departemental studygroup Immune Deficiency, chairman
• Studygroup Infection Prevention WIP, board member
• National Certification Commission Polio, Measles and Rubella eradication, chairman