1. Centre for Infectious Disease Control, RIVM National Institute of Public Health and the Environment, PO Box 1, 3720 BA Bilthoven
2. STI AIDS Netherlands, Amsterdam, Keizersgracht 392, 1016 GB Amsterdam
3. Department of Infectious Diseases, Public Health Service South Limburg, PO Box 2022, 6160 HA Geleen
4. Department of Medical Microbiology, School of Public Health and Primary Care (CAPHRI), Maastricht University Medical Center (MUMC+), PO Box 5800, 6202 AZ Maastricht
5. Department of Infectious Diseases, Municipal Health Service Amsterdam, PO Box 2200, 1000 CE Amsterdam
6. Academic Medical Centre Utrecht, University of Utrecht, Utrecht, Netherlands