Clifton, S; Macdowall, W; Copas, AJ; Tanton, C; Keevil, BG; Lee, DM; Mitchell, KR; Field, N; Sonnenberg, P; Bancroft, J; +5 more... Mercer, CH; Wallace, AM; Johnson, AM; Wellings, K; Wu, F; (2016) Salivary testosterone levels and health status in men and women in the British general population: findings from the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3). The Journal of clinical endocrinology and metabolism. jc20161669. ISSN 0021-972X DOI: https://doi.org/10.1210/jc.2016-1669 Full text not available from this repository.

Drolet, M; Bénard, É; Boily, MC; Ali, H; Baandrup, L; Bauer, H; Beddows, S; Brisson, J; Brotherton, JM; Cummings, T; +20 more... Donovan, B; Fairley, CK; Flagg, EW; Johnson, AM; Kahn, JA; Kavanagh, K; Kjaer, SK; Kliewer, EV; Lemieux-Mellouki, P; Markowitz, L; Mboup, A; Mesher, D; Niccolai, L; Oliphant, J; Pollock, KG; Soldan, K; Sonnenberg, P; Tabrizi, SN; Tanton, C; Brisson, M; (2015) Population-level impact and herd effects following human papillomavirus vaccination programmes: a systematic review and meta-analysis. The Lancet infectious diseases, 15 (5). pp. 565-80. ISSN 1473-3099 DOI: https://doi.org/10.1016/S1473-3099(14)71073-4 Full text not available from this repository.

Field, N; Tanton, C; Mercer, CH; Nicholson, S; Soldan, K; Beddows, S; Ison, C; Johnson, AM; Sonnenberg, P; (2012) Testing for sexually transmitted infections in a population-based sexual health survey: development of an acceptable ethical approach. Journal of medical ethics, 38 (6). pp. 380-2. ISSN 0306-6800 DOI: https://doi.org/10.1136/medethics-2011-100068 Full text not available from this repository.

Legoff, J; Tanton, C; Delaugerre, C; Weiss, HA; Changalucha, J; Ross, DA; Mugeye, K; Belec, L; Hayes, RJ; Watson-Jones, D; (2010) No selection of nucleoside reverse transcriptase inhibitor resistance associated mutations by acyclovir suppressive therapy in herpes simplex virus-2/HIV-1 dually infected persons. AIDS (London, England), 24 (16). pp. 2595-2596. ISSN 0269-9370 DOI: https://doi.org/10.1097/QAD.0b013e32833e5176 Full text not available from this repository.

Legoff, J; Tanton, C; Lecerf, M; Gresenguet, G; Nzambi, K; Bouhlal, H; Weiss, H; Belec, L; (2006) Influence of storage temperature on the stability of HIV-1 RNA and HSV-2 DNA in cervicovaginal secretions collected by vaginal washing. Journal of virological methods, 138 (1-2). pp. 196-200. ISSN 0166-0934 DOI: https://doi.org/10.1016/j.jviromet.2006.07.013 Full text not available from this repository.

Mesher, D; Soldan, K; Lehtinen, M; Beddows, S; Brisson, M; Brotherton, JML; Chow, EPF; Cummings, T; Drolet, M; Fairley, CK; +11 more... Garland, SM; Kahn, JA; Kavanagh, K; Markowitz, L; Pollock, KG; Soderlund-Strand, A; Sonnenberg, P; Tabrizi, SN; Tanton, C; Unger, E; Thomas, SL; (2016) Population-Level Effects of Human Papillomavirus Vaccination Programs on Infections with Nonvaccine Genotypes. Emerging infectious diseases, 22 (10). pp. 1732-1740. ISSN 1080-6040 DOI: https://doi.org/10.3201/eid2210.160675 Full text not available from this repository.

Tanton, C; Soldan, K; Beddows, S; Mercer, CH; Waller, J; Field, N; Clifton, S; Copas, AJ; Panwar, K; Manyenga, P; +5 more... da Silva, F; Wellings, K; Ison, CA; Johnson, AM; Sonnenberg, P; (2015) High-risk human papillomavirus (HPV) infection and cervical cancer prevention in Britain: Evidence of differential uptake of interventions from a probability survey. Cancer epidemiology, biomarkers & prevention, 24 (5). pp. 842-53. ISSN 1055-9965 DOI: https://doi.org/10.1158/1055-9965.EPI-14-1333 Full text not available from this repository.

Watson-Jones, D; Baisley, K; Rusizoka, M; Tanton, C; Mugeye, K; Weiss, HA; Changalucha, J; Clayton, T; Hambleton, I; Ross, DA; +1 more... Hayes, RJ; (2009) Measurement and predictors of adherence in a trial of HSV suppressive therapy in Tanzania. Contemporary clinical trials, 30 (6). pp. 504-12. ISSN 1551-7144 DOI: https://doi.org/10.1016/j.cct.2009.07.002 Full text not available from this repository.

Watson-Jones, D; Wald, A; Celum, C; Lingappa, J; Weiss, HA; Changalucha, J; Baisley, K; Tanton, C; Hayes, RJ; Marshak, JO; +2 more... Gladden, RG; Koelle, DM; (2010) Acyclovir suppression for HIV prevention is not associated with genotypic evidence of acyclovir resistance to HSV-2: Analysis of specimens from three phase III trials. Journal of clinical microbiology, 48 (10). pp. 3496-503. ISSN 0095-1137 DOI: https://doi.org/10.1128/JCM.01263-10 Full text not available from this repository.

Cabecinha, M; Mercer, CH; Gravningen, K; Aicken, C; Jones, KG; Tanton, C; Wellings, K; Sonnenberg, P; Field, N; (2017) Finding sexual partners online: prevalence and associations with sexual behaviour, STI diagnoses and other sexual health outcomes in the British population. Sexually transmitted infections. ISSN 1368-4973 DOI: https://doi.org/10.1136/sextrans-2016-052994

Casey, SE; McNab, SE; Tanton, C; Odong, J; Testa, AC; Lee-Jones, L; (2013) Availability of long-acting and permanent family-planning methods leads to increase in use in conflict-affected northern Uganda: evidence from cross-sectional baseline and endline cluster surveys. Global public health, 8 (3). pp. 284-97. ISSN 1744-1692 DOI: https://doi.org/10.1080/17441692.2012.758302

Clifton, S; Nardone, A; Field, N; Mercer, CH; Tanton, C; Macdowall, W; Johnson, AM; Sonnenberg, P; (2016) HIV testing, risk perception, and behaviour in the British population. AIDS (London, England), 30 (6). pp. 943-52. ISSN 0269-9370 DOI: https://doi.org/10.1097/QAD.0000000000001006

Datta, J; Palmer, MJ; Tanton, C; Gibson, LJ; Jones, KG; Macdowall, W; Glasier, A; Sonnenberg, P; Field, N; Mercer, CH; +2 more... Johnson, AM; Wellings, K; (2016) Prevalence of infertility and help seeking among 15 000 women and men. Human reproduction (Oxford, England). ISSN 0268-1161 DOI: https://doi.org/10.1093/humrep/dew123

Erens, B; Couper, MP; Conrad, F; Clifton, S; Tanton, C; Phelps, A; Datta, J; Mercer, CH; Sonnenberg, P; Prah, P; +4 more... Mitchell, KR; Wellings, K; Johnson, AM; Copas, AJ; (2014) Nonprobability web surveys to measure sexual behaviors and attitudes in the general population: a comparison with a probability sample interview survey. Journal of medical Internet research, 16 (12). e276. ISSN 1439-4456 DOI: https://doi.org/10.2196/jmir.3382

Erens, B; Phelps, A; Clifton, S; Mercer, CH; Tanton, C; Hussey, D; Sonnenberg, P; Macdowall, W; Field, N; Datta, J; +4 more... Mitchell, K; Copas, AJ; Wellings, K; Johnson, AM; (2013) Methodology of the third British National Survey of Sexual Attitudes and Lifestyles (Natsal-3). Sexually transmitted infections, 90 (2). pp. 84-9. ISSN 1368-4973 DOI: https://doi.org/10.1136/sextrans-2013-051359

Field, N; Clifton, S; Alexander, S; Ison, CA; Hughes, G; Beddows, S; Tanton, C; Soldan, K; Coelho da Silva, F; Mercer, CH; +3 more... Wellings, K; Johnson, AM; Sonnenberg, P; (2014) Confirmatory assays are essential when using molecular testing for Neisseria gonorrhoeae in low-prevalence settings: insights from the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3). Sexually transmitted infections, 91 (5). pp. 338-41. ISSN 1368-4973 DOI: https://doi.org/10.1136/sextrans-2014-051850

Field, N; Mercer, CH; Sonnenberg, P; Tanton, C; Clifton, S; Mitchell, KR; Erens, B; MacDowall, W; Wu, F; Datta, J; +6 more... Stevens, A; Prah, P; Copas, AJ; Phelps, A; Wellings, K; Johnson, AM; (2013) Associations between health and sexual lifestyles in Britain: findings from the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3). Lancet. ISSN 0140-6736 DOI: https://doi.org/10.1016/S0140-6736(13)62222-9

Field, N; Prah, P; Mercer, CH; Rait, G; King, M; Cassell, JA; Tanton, C; Heath, L; Mitchell, KR; Clifton, S; +4 more... Datta, J; Wellings, K; Johnson, AM; Sonnenberg, P; (2016) Are depression and poor sexual health neglected comorbidities? Evidence from a population sample. BMJ open, 6 (3). e010521. ISSN 2044-6055 DOI: https://doi.org/10.1136/bmjopen-2015-010521

Geary, RS; Tanton, C; Erens, B; Clifton, S; Prah, P; Wellings, K; Mitchell, KR; Datta, J; Gravningen, K; Fuller, E; +3 more... Johnson, AM; Sonnenberg, P; Mercer, CH; (2018) Sexual identity, attraction and behaviour in Britain: The implications of using different dimensions of sexual orientation to estimate the size of sexual minority populations and inform public health interventions. PloS one, 13 (1). e0189607. ISSN 1932-6203 DOI: https://doi.org/10.1371/journal.pone.0189607

Graham, CA; Mercer, CH; Tanton, C; Jones, KG; Johnson, AM; Wellings, K; Mitchell, KR; (2017) What factors are associated with reporting lacking interest in sex and how do these vary by gender? Findings from the third British national survey of sexual attitudes and lifestyles. BMJ open, 7 (9). e016942. ISSN 2044-6055 DOI: https://doi.org/10.1136/bmjopen-2017-016942

Holdsworth, E; Trifonova, V; Tanton, C; Kuper, H; Datta, J; Macdowall, W; Mercer, CH; (2018) Sexual behaviours and sexual health outcomes among young adults with limiting disabilities: findings from third British National Survey of Sexual Attitudes and Lifestyles (Natsal-3). BMJ open, 8 (7). e019219. ISSN 2044-6055 DOI: https://doi.org/10.1136/bmjopen-2017-019219

Homfray, V; Tanton, C; Miller, RF; Beddows, S; Field, N; Sonnenberg, P; Wellings, K; Panwar, K; Johnson, AM; Mercer, CH; (2015) Male Circumcision and STI Acquisition in Britain: Evidence from a National Probability Sample Survey. PloS one, 10 (6). e0130396. ISSN 1932-6203 DOI: https://doi.org/10.1371/journal.pone.0130396

Homfray, V; Tanton, C; Mitchell, KR; Miller, RF; Field, N; Macdowall, W; Wellings, K; Sonnenberg, P; Johnson, AM; Mercer, CH; (2015) Examining the association between male circumcision and sexual function: evidence from a British probability survey. AIDS (London, England), 29 (11). pp. 1411-1416. ISSN 0269-9370 DOI: https://doi.org/10.1097/QAD.0000000000000745

Jones, KG; Johnson, AM; Wellings, K; Sonnenberg, P; Field, N; Tanton, C; Erens, B; Clifton, S; Datta, J; Mitchell, KR; +2 more... Prah, P; Mercer, CH; (2014) The prevalence of, and factors associated with, paying for sex among men resident in Britain: findings from the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3). Sexually transmitted infections, 91 (2). pp. 116-23. ISSN 1368-4973 DOI: https://doi.org/10.1136/sextrans-2014-051683

Keevil, BG; Clifton, S; Tanton, C; Macdowall, W; Copas, AJ; Lee, D; Field, N; Mitchell, KR; Sonnenberg, P; Bancroft, J; +4 more... Mercer, CH; Johnson, AM; Wellings, K; Wu, FCW; (2017) Distribution of Salivary Testosterone in Men and Women in a British General Population-Based Sample: The Third National Survey of Sexual Attitudes and Lifestyles (Natsal-3). J Endocr Soc, 1 (1). pp. 14-25. ISSN 2472-1972 DOI: https://doi.org/10.1210/js.2016-1029

Lewis, R; Tanton, C; Mercer, CH; Mitchell, KR; Palmer, M; Macdowall, W; Wellings, K; (2017) Heterosexual Practices Among Young People in Britain: Evidence From Three National Surveys of Sexual Attitudes and Lifestyles. The Journal of adolescent health, 61 (6). pp. 694-702. ISSN 1054-139X DOI: https://doi.org/10.1016/j.jadohealth.2017.07.004

Lin, A; Ong, KJ; Hobbelen, P; King, E; Mesher, D; Edmunds, WJ; Sonnenberg, P; Gilson, R; Bains, I; Choi, YH; +3 more... Tanton, C; Soldan, K; Jit, M; (2016) Impact and cost-effectiveness of selective human papillomavirus vaccination of men who have sex with men. Clinical infectious diseases, 64 (5). pp. 580-588. ISSN 1058-4838 DOI: https://doi.org/10.1093/cid/ciw845

MacDowall, W; Gibson, L; Tanton, C; Mercer, CH; Lewis, R; Clifton, S; Field, N; Datta, J; Mitchell, KR; Sonnenberg, P; +6 more... Erens, B; Copas, AJ; Phelps, A; Prah, P; Johnson, AM; Wellings, K; (2013) Lifetime prevalence, associated factors, and circumstances of non-volitional sex in women and men in Britain: findings from the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3). Lancet. ISSN 0140-6736 DOI: https://doi.org/10.1016/S0140-6736(13)62300-4

Macdowall, W; Jones, KG; Tanton, C; Clifton, S; Copas, AJ; Mercer, CH; Palmer, MJ; Lewis, R; Datta, J; Mitchell, KR; +4 more... Field, N; Sonnenberg, P; Johnson, AM; Wellings, K; (2015) Associations between source of information about sex and sexual health outcomes in Britain: findings from the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3). BMJ open, 5 (3). e007837. ISSN 2044-6055 DOI: https://doi.org/10.1136/bmjopen-2015-007837

Mercer, CH; Jones, KG; Johnson, AM; Lewis, R; Mitchell, KR; Gravningen, K; Clifton, S; Tanton, C; Sonnenberg, P; Wellings, K; +2 more... Cassell, JA; Estcourt, CS; (2016) How can we objectively categorise partnership type? A novel classification of population survey data to inform epidemiological research and clinical practice. Sexually transmitted infections, 93 (2). pp. 129-136. ISSN 1368-4973 DOI: https://doi.org/10.1136/sextrans-2016-052646

Mercer, CH; Prah, P; Field, N; Tanton, C; Macdowall, W; Clifton, S; Hughes, G; Nardone, A; Wellings, K; Johnson, AM; +1 more... Sonnenberg, P; (2016) The health and well-being of men who have sex with men (MSM) in Britain: Evidence from the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3). BMC public health, 16. p. 525. ISSN 1471-2458 DOI: https://doi.org/10.1186/s12889-016-3149-z

Mercer, CH; Tanton, C; Prah, P; Erens, B; Sonnenberg, P; Clifton, S; MacDowall, W; Lewis, R; Field, N; Datta, J; +4 more... Copas, AJ; Phelps, A; Wellings, K; Johnson, AM; (2013) Changes in sexual attitudes and lifestyles in Britain through the life course and over time: findings from the National Surveys of Sexual Attitudes and Lifestyles (Natsal). Lancet. ISSN 0140-6736 DOI: https://doi.org/10.1016/S0140-6736(13)62035-8

Mitchell, KR; Mercer, CH; Prah, P; Clifton, S; Tanton, C; Wellings, K; Copas, A; (2018) Why Do Men Report More Opposite-Sex Sexual Partners Than Women? Analysis of the Gender Discrepancy in a British National Probability Survey. Journal of sex research. pp. 1-8. ISSN 0022-4499 DOI: https://doi.org/10.1080/00224499.2018.1481193

Mitchell, KR; Prah, P; Mercer, CH; Datta, J; Tanton, C; Macdowall, W; Copas, AJ; Clifton, S; Sonnenberg, P; Field, N; +2 more... Johnson, AM; Wellings, K; (2015) Medicated sex in Britain: evidence from the third National Survey of Sexual Attitudes and Lifestyles. Sexually transmitted infections, 92 (1). pp. 32-8. ISSN 1368-4973 DOI: https://doi.org/10.1136/sextrans-2015-052094

Odutola, A; Baisley, K; Hayes, RJ; Rusizoka, M; Tanton, C; Weiss, HA; Changalucha, J; Ross, DA; Watson-Jones, D; (2012) Pregnancy and contraceptive use among women participating in an HIV prevention trial in Tanzania. Sexually transmitted infections, 88 (6). pp. 436-43. ISSN 1368-4973 DOI: https://doi.org/10.1136/sextrans-2011-050412

Paquette, R; Tanton, C; Burns, F; Prah, P; Shahmanesh, M; Field, N; Macdowall, W; Gravningen, K; Sonnenberg, P; Mercer, CH; (2017) Illicit drug use and its association with key sexual risk behaviours and outcomes: Findings from Britain's third National Survey of Sexual Attitudes and Lifestyles (Natsal-3). PloS one, 12 (5). e0177922. ISSN 1932-6203 DOI: https://doi.org/10.1371/journal.pone.0177922

Pound, P; Denford, S; Shucksmith, J; Tanton, C; Johnson, AM; Owen, J; Hutten, R; Mohan, L; Bonell, C; Abraham, C; +1 more... Campbell, R; (2017) What is best practice in sex and relationship education? A synthesis of evidence, including stakeholders' views. BMJ open, 7 (5). e014791. ISSN 2044-6055 DOI: https://doi.org/10.1136/bmjopen-2016-014791

Prah, P; Copas, AJ; Mercer, CH; Clifton, S; Erens, B; Phelps, A; Tanton, C; Sonnenberg, P; MacDowall, W; Wellings, K; +1 more... Johnson, AM; (2013) Consistency in reporting sensitive sexual behaviours in Britain: change in reporting bias in the second and third National Surveys of Sexual Attitudes and Lifestyles (Natsal-2 and Natsal-3). Sexually transmitted infections, 90 (2). pp. 90-93. ISSN 1368-4973 DOI: https://doi.org/10.1136/sextrans-2013-051360

Sonnenberg, P; Clifton, S; Beddows, S; Field, N; Soldan, K; Tanton, C; Mercer, CH; Silva, FCD; Alexander, S; Copas, AJ; +7 more... Phelps, A; Erens, B; Prah, P; MacDowall, W; Wellings, K; Ison, CA; Johnson, AM; (2013) Prevalence, risk factors, and uptake of interventions for sexually transmitted infections in Britain: findings from the National Surveys of Sexual Attitudes and Lifestyles (Natsal). Lancet. ISSN 0140-6736 DOI: https://doi.org/10.1016/S0140-6736(13)61947-9

Sonnenberg, P; Ison, CA; Clifton, S; Field, N; Tanton, C; Soldan, K; Beddows, S; Alexander, S; Khanom, R; Saunders, P; +4 more... Copas, AJ; Wellings, K; Mercer, CH; Johnson, AM; (2015) Epidemiology of Mycoplasma genitalium in British men and women aged 16-44 years: evidence from the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3). International journal of epidemiology, 44 (6). pp. 1982-94. ISSN 0300-5771 DOI: https://doi.org/10.1093/ije/dyv194

Tanton, C; Geary, RS; Clifton, S; Field, N; Heap, KL; Mapp, F; Hughes, G; Johnson, AM; Cassell, JA; Sonnenberg, P; +1 more... Mercer, CH; (2017) Sexual health clinic attendance and non-attendance in Britain: findings from the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3). Sexually transmitted infections. ISSN 1368-4973 DOI: https://doi.org/10.1136/sextrans-2017-053193

Tanton, C; Johnson, AM; Macdowall, W; Datta, J; Clifton, S; Field, N; Mitchell, KR; Wellings, K; Sonnenberg, P; Mercer, CH; (2016) Forming new sex partnerships while overseas: findings from the third British National Survey of Sexual Attitudes & Lifestyles (Natsal-3). Sexually transmitted infections, 92 (6). pp. 415-23. ISSN 1368-4973 DOI: https://doi.org/10.1136/sextrans-2015-052459

Tanton, C; Jones, KG; Macdowall, W; Clifton, S; Mitchell, KR; Datta, J; Lewis, R; Field, N; Sonnenberg, P; Stevens, A; +3 more... Wellings, K; Johnson, AM; Mercer, CH; (2015) Patterns and trends in sources of information about sex among young people in Britain: evidence from three National Surveys of Sexual Attitudes and Lifestyles. BMJ open, 5 (3). e007834. ISSN 2044-6055 DOI: https://doi.org/10.1136/bmjopen-2015-007834

Tanton, C; Mesher, D; Beddows, S; Soldan, K; Clifton, S; Panwar, K; Field, N; Mercer, CH; Johnson, AM; Sonnenberg, P; (2017) Human papillomavirus (HPV) in young women in Britain: Population-based evidence of the effectiveness of the bivalent immunisation programme and burden of quadrivalent and 9-valent vaccine types. Papillomavirus research (Amsterdam, Netherlands), 3. pp. 36-41. ISSN 2405-8521 DOI: https://doi.org/10.1016/j.pvr.2017.01.001

Tanton, C; Weiss, HA; LeGoff, J; Changalucha, J; Clayton, TC; Ross, DA; Belec, L; Hayes, RJ; Watson-Jones, D; (2011) Patterns of herpes simplex virus shedding over 1 month and the impact of acyclovir and HIV in HSV-2-seropositive women in Tanzania. Sexually transmitted infections, 87 (5). pp. 406-11. ISSN 1368-4973 DOI: https://doi.org/10.1136/sti.2010.048496

Wayal, S; Hughes, G; Sonnenberg, P; Mohammed, H; Copas, AJ; Gerressu, M; Tanton, C; Furegato, M; Mercer, CH; (2017) Ethnic variations in sexual behaviours and sexual health markers: findings from the third British National Survey of Sexual Attitudes and Lifestyles (Natsal-3). The lancet Public health, 2 (10). e458-e472. ISSN 2468-2667 DOI: https://doi.org/10.1016/S2468-2667(17)30159-7

Wellings, K; Jones, K; Mercer, CH; Tanton, C; Clifton, S; Datta, J; Copas, AJ; Erens, B; Gibson, L; MacDowall, W; +3 more... Sonnenberg, P; Phelps, A; Johnson, AM; (2013) The prevalence of unplanned pregnancy and associated factors in Britain: findings from the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3). Lancet. ISSN 0140-6736 DOI: https://doi.org/10.1016/S0140-6736(13)62071-1

Wellings, K; Palmer, MJ; Geary, RS; Gibson, LJ; Copas, A; Datta, J; Glasier, A; Scott, RH; Mercer, CH; Erens, B; +6 more... Macdowall, W; French, RS; Jones, K; Johnson, AM; Tanton, C; Wilkinson, P; (2016) Changes in conceptions in women younger than 18 years and the circumstances of young mothers in England in 2000-12: an observational study. Lancet, 388 (10044). pp. 586-95. ISSN 0140-6736 DOI: https://doi.org/10.1016/S0140-6736(16)30449-4

Woodhall, SC; Soldan, K; Sonnenberg, P; Mercer, CH; Clifton, S; Saunders, P; da Silva, F; Alexander, S; Wellings, K; Tanton, C; +4 more... Field, N; Copas, AJ; Ison, CA; Johnson, AM; (2015) Is chlamydia screening and testing in Britain reaching young adults at risk of infection? Findings from the third National Survey of Sexual Attitudes and Lifestyles (Natsal-3). Sexually transmitted infections, 92 (3). pp. 218-27. ISSN 1368-4973 DOI: https://doi.org/10.1136/sextrans-2015-052013