Chlamydia, gonorrhoea, trichomoniasis and syphilis: global prevalence and incidence estimates, 2016.

Objective: To generate estimates of the global prevalence and incidence of urogenital infection with chlamydia, gonorrhoea, trichomoniasis and syphilis in women and men, aged 15-49 years, in 2016.

Methods: For chlamydia, gonorrhoea and trichomoniasis, we systematically searched for studies conducted between 2009 and 2016 reporting prevalence. We also consulted regional experts. To generate estimates, we used Bayesian meta-analysis. For syphilis, we aggregated the national estimates generated by using Spectrum-STI.

Findings: For chlamydia, gonorrhoea and/or trichomoniasis, 130 studies were eligible. For syphilis, the Spectrum-STI database contained 978 data points for the same period. The 2016 global prevalence estimates in women were: chlamydia 3.8% (95% uncertainty interval, UI: 3.3-4.5); gonorrhoea 0.9% (95% UI: 0.7-1.1); trichomoniasis 5.3% (95% UI:4.0-7.2); and syphilis 0.5% (95% UI: 0.4-0.6). In men prevalence estimates were: chlamydia 2.7% (95% UI: 1.9-3.7); gonorrhoea 0.7% (95% UI: 0.5-1.1); trichomoniasis 0.6% (95% UI: 0.4-0.9); and syphilis 0.5% (95% UI: 0.4-0.6). Total estimated incident cases were 376.4 million: 127.2 million (95% UI: 95.1-165.9 million) chlamydia cases; 86.9 million (95% UI: 58.6-123.4 million) gonorrhoea cases; 156.0 million (95% UI: 103.4-231.2 million) trichomoniasis cases; and 6.3 million (95% UI: 5.5-7.1 million) syphilis cases.

Conclusion: Global estimates of prevalence and incidence of these four curable sexually transmitted infections remain high. The study highlights the need to expand data collection efforts at country level and provides an initial baseline for monitoring progress of the 1.