1. Department of General Practice/Family Medicine, Division of Clinical Methods and Public Health, Academic Medical Center, Amsterdam, The Netherlands
2. Amsterdam Institute for Global Health and Development (AIGHD), Amsterdam, The Netherlands
3. STI AIDS Netherlands (Soa Aids Nederland), Amsterdam, Netherlands
4. Epidemiology & Surveillance Unit, Centre for Infectious Disease Control, National Institute of Public Health and the Environment (RIVM), Bilthoven, The Netherlands