1. Centre for Epidemiology and Biostatistics, Melbourne School of Population and Global Health, University of Melbourne, Melbourne, Australia
2. Population Health Sciences, University of Bristol, Oakfield House, Oakfield Grove, Bristol, UK
3. National Institute for Health Research Health Protection Research Unit in Evaluation of Interventions, University of Bristol, Bristol, UK
4. WHO Collaborating Centre for Gonorrhoea and Other STIs, National Reference Laboratory for Sexually Transmitted Infections, Department of Laboratory Medicine, Microbiology, Örebro University, Örebro, Sweden