Footnotes

• Handling editor Sarah K Edwards

• Contributors NE conceived the idea for the paper. All authors (LMD, PB, SW, SC, JOC, JAC and NE) contributed to writing early drafts of the paper. Case study 1 was conducted by JOC. Case studies 2 and 4 were conducted by NE and case study 3 was conducted by LMD. LMD and NE prepared the final manuscript with contributions from all coauthors. All authors read and approved the final manuscript.

• Funding This paper is an independent research by the National Institute for Health Research. The research is funded by the National Institute for Health Research Health Protection Research Unit (NIHR HPRU) in Blood Borne and Sexually Transmitted Infections at University College London, in partnership with Public Health England and in collaboration with the London School of Hygiene and Tropical Medicine (grant number: HPRU-2012-10023). Case study 4 presents independent research commissioned by the NIHR, under the Research for Patient Benefit Programme (PB-PG-0407-13149).

• Disclaimer The views expressed in this publication are those of the authors and not necessarily those of the NIHR, the Department of Health and Social Care, or Public Health England.

• Competing interests None declared.

• Patient consent for publication Not required.

• Ethics approval Not required.

• Provenance and peer review Commissioned; externally peer reviewed.