Footnotes

• Twitter Follow John Saunders at @saunders_j

• Competing interests Dr. Horner reports personal fees from Aquarius Population Health, grants, personal fees and non-financial support from Cepheid, personal fees from Crown Prosecution Service, personal fees from British Association for Sexual Health and HIV, grants from Mast Group Ltd, grants and personal fees from Hologic, outside the submitted work; In addition, Dr. Horner has a patent A sialidase spot test to diagnose bacterial vaginosis issued to University of Bristol.

• Provenance and peer review Commissioned; internally peer reviewed.