1. Centre for the Evaluation of Vaccination, Vaccine and Infectious Disease Institute, University of Antwerp , Wilrijk, Antwerp , Belgium
2. Laboratory of Medical Microbiology, Vaccine and Infectious Disease Institute, University of Antwerp , Wilrijk , Antwerp , Belgium
3. Reference Centre for Pneumococci, University Hospitals Leuven , Leuven , Belgium
4. Centre for Statistics, Hasselt University , Diepenbeek , Belgium
5. Centre for Health Economics Research and Modelling Infectious Diseases, University of Antwerp , Wilrijk , Antwerp , Belgium