1. Oslo University Hospital, Department of Venereology, The Olafia Clinic, Norwegian National Advisory Unit on Sexually Transmitted Infections, Oslo, Norway
2. Fürst Medisinsk Laboratorium, Oslo, Norway
3. Department of Infectious Disease Epidemiology and Modelling, Norwegian Institute of Public Health, Oslo, Norway
4. Department of Biostatistics, Oslo Centre for Biostatistics and Epidemiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
5. Faculty of Medicine, University of Oslo, Oslo, Norway