1. Greater Manchester Health Protection Team, Public Health England, Manchester M1 3BN, UK
2. RUClear Chlamydia Screening Programme, Central Manchester University Hospitals NHS Foundation Trust, Manchester, UK
3. Public Health Laboratory, Public Health England, Manchester, UK
4. Faculty of Medical and Human Sciences, The University of Manchester, Manchester, UK
5. Department of Sexual Health and HIV, North Manchester General Hospital, Manchester, UK
6. Cheshire and Mersey Health Protection Team, Public Health England, Manchester, UK