1. Department of Microbiology, Immunology and Transplantation, KU Leuven, Leuven, Belgium
2. Department of Geriatric Medicine, University Hospitals Leuven, Leuven, Belgium
3. Department of Public Health & Primary Care, KU Leuven, Leuven, Belgium
4. Leuven University Vaccinology Centre, Leuven, Belgium
5. Department of General Internal Medicine, University Hospitals Leuven, Leuven, Belgium
6. National Reference Centre for Streptococcus Pneumoniae, University Hospitals Leuven, Leuven, Belgium