Global Estimates of the Prevalence and Incidence of Four Curable Sexually Transmitted Infections in 2012 Based on Systematic Review and Global Reporting.

BACKGROUND: Quantifying sexually transmitted infection (STI) prevalence and incidence is important for planning interventions and advocating for resources. The World Health Organization (WHO) periodically estimates global and regional prevalence and incidence of four curable STIs: chlamydia, gonorrhoea, trichomoniasis and syphilis. METHODS AND FINDINGS: WHO's 2012 estimates were based upon literature reviews of prevalence data from 2005 through 2012 among general populations for genitourinary infection with chlamydia, gonorrhoea, and trichomoniasis, and nationally reported data on syphilis seroprevalence among antenatal care attendees. Data were standardized for laboratory test type, geography, age, and high risk subpopulations, and combined using a Bayesian meta-analytic approach. Regional incidence estimates were generated from prevalence estimates by adjusting for average duration of infection. In 2012, among women aged 15-49 years, the estimated global prevalence of chlamydia was 4.2% (95% uncertainty interval (UI): 3.7-4.7%), gonorrhoea 0.8% (0.6-1.0%), trichomoniasis 5.0% (4.0-6.4%), and syphilis 0.5% (0.4-0.6%); among men, estimated chlamydia prevalence was 2.7% (2.0-3.6%), gonorrhoea 0.6% (0.4-0.9%), trichomoniasis 0.6% (0.4-0.8%), and syphilis 0.48% (0.3-0.7%). These figures correspond to an estimated 131 million new cases of chlamydia (100-166 million), 78 million of gonorrhoea (53-110 million), 143 million of trichomoniasis (98-202 million), and 6 million of syphilis (4-8 million). Prevalence and incidence estimates varied by region and sex. CONCLUSIONS: Estimates of the global prevalence and incidence of chlamydia, gonorrhoea, trichomoniasis, and syphilis in adult women and men remain high, with nearly one million new infections with curable STI each day. The estimates highlight the urgent need for the public health community to ensure that well-recognized effective interventions for STI prevention, screening, diagnosis, and treatment are made more widely available. Improved estimation methods are needed to allow use of more varied data and generation of estimates at the national level.

Reaching beyond pregnant women to eliminate mother-to-child transmission of syphilis in Africa.

Congenital syphilis is a devastating disease that can be prevented by screening and treatment of infected pregnant women. The WHO is leading a global initiative to eliminate mother-to-child-transmission of syphilis with a goal of ≤50 congenital syphilis cases per 100,000 live births and targets of 95% antenatal care, 95% syphilis testing, and 95% treatment coverage. We estimated current congenital syphilis rates for 43 African countries, and additional scenarios in a subset of 9 countries. Our analysis suggested that only 4 of 43 countries are likely to currently have a congenital syphilis rate ≤50 per 100,000 live births, and none of the 9 countries could reach this goal even in 5 different scenarios with improved services. To achieve the eliminate mother-to-child-transmission goal, it appears necessary to intervene beyond services for pregnant women, and decrease prevalence of syphilis in the general population as well.