Epidemiology of Treponema pallidum, Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, and herpes simplex virus type 2 among female sex workers in the Middle East and North Africa: systematic review and meta-analytics

Background The epidemiology of sexually transmitted infections (STIs) and the role of commercial heterosexual sex networks in driving STI transmission in the Middle East and North Africa (MENA) region remain largely unknown. Objective To characterize the epidemiology of Treponema pallidum (syphilis), Chlamydia trachomatis, Neisseria gonorrhoeae, Trichomonas vaginalis, and herpes simplex virus type 2 (HSV-2) among female sex workers (FSWs) in MENA using an in-depth quantitative assessment. Methods A systematic review on ten international, regional, and country-level databases was conducted, and reported following PRISMA guidelines. Pooled prevalences of current and/or ever infection for each STI were estimated using random-effects meta-analyses. Sources of between-study heterogeneity were investigated through random-effects meta-regressions. Results One T. pallidum incidence study and 144 STI prevalence studies were identified for 45 812 FSWs in 13 MENA countries. The pooled prevalence of current infection was 12.7% (95% confidence interval (CI) = 8.5%-17.7%) for T. pallidum, 14.4% (95% CI = 8.2%-22.0%) for C. trachomatis, 5.7% (95% CI = 3.5%-8.4%) for N. gonorrhoeae, and 7.1% (95% CI = 4.3%-10.5%) for T. vaginalis. The pooled prevalence of ever infection (seropositivity using antibody testing) was 12.8% (95% CI = 9.4%-16.6%) for T. pallidum, 80.3% (95% CI = 53.2%-97.6%) for C. trachomatis, and 23.7% (95% CI = 10.2%-40.4%) for HSV-2. The multivariable meta-regression for T. pallidum infection demonstrated strong subregional differences, with the Horn of Africa and North Africa showing, respectively 6-fold (adjusted odds ratio (AOR): 6.4; 95% CI = 2.5-16.7) and 5-fold (AOR = 5.0; 95% CI = 2.5-10.6) higher odds of infection than Eastern MENA. There was also strong evidence for declining T. pallidum odds of infection at 7% per year (AOR = 0.93; 95% CI = 0.88-0.98). Study-specific factors including diagnostic method, sample size, sampling methodology, and response rate, were not associated with syphilis infection. The multivariable model explained 48.5% of the variation in T. pallidum prevalence. Conclusions STI infection levels among FSWs in MENA are considerable, supporting a key role for commercial heterosexual sex networks in transmission dynamics, and highlighting the health needs of this neglected and vulnerable population. Syphilis prevalence in FSWs appears to have been declining for at least three decades. Gaps in evidence persist for multiple countries.

3 Section/topic # Checklist item Reported in main text Study characteristics 18 For each study, present characteristics for which data were extracted (e.g., study size, PICOS, follow-up period) and provide the citations.
p. 11 and Tables 1-3 Risk of bias within studies 19 Present data on risk of bias of each study and, if available, any outcome-level assessment (see Item 12).
p. 11-and Tables S5-S6 in the OSD Results of individual studies 20 For all outcomes considered (benefits or harms), present, for each study: (a) simple summary data for each intervention group and (b) effect estimates and confidence intervals, ideally with a forest plot.
p. 12 and Table 4 Synthesis of results 21 Present results of each meta-analysis done, including confidence intervals and measures of consistency.
p. 12 and Table 4 Risk of bias across studies 22 Present results of any assessment of risk of bias across studies (see Item 15). p. 11-12 and Tables S5-S6 in the OSD Additional analysis 23 Give results of additional analyses, if done (e.g., sensitivity or subgroup analyses, meta-regression [see Item 16]).
p. 12-13 and Table 5 DISCUSSION Summary of evidence 24 Summarize the main findings including the strength of evidence for each main outcome; consider their relevance to key groups (e.g., health care providers, users, and policy makers).
p. 14-17 Limitations 25 Discuss limitations at study and outcome level (e.g., risk of bias), and at review level (e.g., incomplete retrieval of identified research, reporting bias).
p. 17 Sex work exp prostitution/ or exp casual sex/ or exp transactional sex/ or exp group sex/ or exp sex tourism/ or exp sexual promiscuity/ or exp extramarital sex/ or exp premarital sex/ or exp sexual relation/ or exp sexual partners/ or ((exp sex trafficking/ or exp sexual exploitation/ or exp sexual coercion/) NOT Child) or (sex* work* or sexwork* or sex-work* or sex partner* or sexual partner* or sexual contact* or premarital sex or premarital sexual or premarital relation* or pre-marital sex or pre-marital sexual or pre-marital relation* or pre marital sex or pre marital sexual or pre marital relation* or extramarital sex or extramarital sexual or extramarital relation* or extra-marital sex or extra-marital sexual or extra-marital relation* or extra marital sex or extra marital sexual or extra marital relation* or illicit sex or illicit sexual or illicit relation* or illegal sex or illegal sexual or illegal relation* or (out* ADJ1 marriage) or illegal social behavio?r or adultery or prostitut* or promiscu* or FSW or FSWs or CSW or CSWs or SW or SWs or TSW or TSWs or TS or (women ADJ4 sex*) or (Travailleuse* ADJ1 sex*) or bar girl* or call girl* or callgirl* or escort* or masseuse* or hostess* or female entertain* or sex       The same population may have contributed different measures for both current infection and ever (seropositivity using antibody testing) infection. * Medians and ranges were calculated based on the stratified prevalence measures. † Q: the Cochran's Q statistic is a measure assessing the existence of heterogeneity in effect size (here, prevalence) across studies. ‡ I 2 : a measure assessing the magnitude of between-study variation that is due to differences in effect size (here, prevalence) across studies rather than chance. § Prediction interval: a measure estimating the 95% interval of the distribution of true effect sizes (here, prevalence measures). ‖ Ever infection indicates seropositivity using antibody testing. CI, confidence interval. FSWs, female sex workers.