[1] Univ Bristol, Bristol Med Sch, Populat Hlth Sci, Ctr Acad Primary Care, 39 Whatley Rd, Bristol BS8 2PS, Avon, England
[2] Univ Hosp Bristol & Weston NHS Fdn Trust, Natl Inst Hlth Res, Appl Res Collaborat West NIHR ARC West, Bristol, Avon, England
[3] Univ Bristol, NIHR Hlth Protect Res Unit HPRU Behav Sci & Evalu, Bristol, Avon, England
[4] Univ West England, Dept Nursing & Midwifery, Bristol, Avon, England
[5] Publ Hlth England, Natl Infect Serv, Field Serv, Bristol, Avon, England
[6] Univ Hosp Bristol & Weston NHS Fdn Trust, UNITY Sexual Hlth, Bristol, Avon, England
[7] Publ Hlth England South West Reg Lab, Bristol, Avon, England