Trends in Adult Chlamydia and Gonorrhea Prevalence, Incidence and Urethral Discharge Case Reporting in Morocco over 1995-2015-Estimates Using the Spectrum-Sexually Transmitted Infection Model

Abstract

Background: Evolving health priorities and resource constraints mean that countries require data on sexually transmitted infections (STI) trends to inform program planning and resource allocation.

Methods: The Spectrum modeling tool estimated prevalence and incidence of gonorrhea and chlamydia in Morocco's 15- to 49-year-old population, based on prevalence surveys. Incident cases, broken down between symptomatic and asymptomatic, and treated versus untreated, were compared with urethral discharge (UD) case reports, to estimate reporting completeness among treated UD cases.

Results: Gonorrhea prevalence was estimated at 0.37% (95% confidence interval [CI], 0.14-1.0%) in women and 0.32% (0.12-0.87%) in men in 2015; chlamydia prevalences were 3.8% (95% CI, 2.1-6.4%) and 3.0% (95% CI, 1.7-5.1%). Corresponding estimated numbers of new cases in women and men in 2015 were 79,598 (95% CI, 23,918-256,206) and 112,013 (95% CI, 28,700-307,433) for gonorrhea, and 291,908 (95% CI, 161,064-524,270) and 314,032 (95% CI, 186,076-559,133) for chlamydia. Gonorrhea and chlamydia prevalence had declined by an estimated 41% and 27%, respectively, over 1995 to 2015. Prevalence declines probably related to improved STI treatment coverage, and decreasing risk behaviors. Reporting completeness among treated UD cases was estimated at 46% to 77% in 2015. Reported UD cases corresponded to 13% of all estimated (symptomatic and asymptomatic) gonorrhea and chlamydia cases.

Conclusions: STI declines and improvements in treatment coverage are consistent with Morocco's introduction of syndromic management in 2000, scale-up of prevention, and declining human immunodeficiency virus incidence. While gonorrhea is four-fold more common as cause of clinical UD cases than chlamydia, Morocco continues to suffer a large, untreated burden of chlamydia. Reliable monitoring of both STIs requires new periodic surveys and/or novel forms of affordable surveillance beyond high-risk populations.

Figure 1

Prevalence of gonorrhea and chlamydia in women 15–49 years in Morocco: Spectrum estimates and underlying data. Data are shown after adjustments for diagnostic test performance, urban/rural differences, and missing high-risk populations, as described in Methods. Regional estimates shown were those also used in the prevalence fitting, at a 1% weight relative to the national data points (see Methods), from WHO for the year 2012. Dashed lines are 95% CIs around the Spectrum estimate. Data and prevalence estimates shown are for women 15 t o 49 years.

Figure 2

Incidence of gonorrhea and chlamydia cases, per 100,000 adult men or women (15–49 years) in Morocco. Solid lines are best estimates; dotted lines are the 95% CIs. Incidence was based on gonorrhea and chlamydia prevalence estimates from Spectrum simulations, and the assumption that treatment coverage for both gonorrhea and chlamydia in 1995 (21% and 3.6%) had been half that at 2015 (42% and 7.2%), with a linear increase in treatment coverage over 1995–2015 Supplemental Digital Content (SDC) 3, http://links.lww.com/OLQ/A179, and corresponding shortening of average episode duration Supplemental Digital Content (SDC) 3, http://links.lww.com/OLQ/A179. Dashed lines are 95% Confidence Intervals around the Spectrum estimate.

Figure 3

Spectrum-estimated incident gonorrhea and chlamydia cases, in men 15 to 64 years, by treatment and reporting status, Morocco. Reporting completeness among UD cases treated in clinics shown, is the average of the reporting completeness estimates calculated relative to gonorrhea incidence, and the completeness relative to chlamydia incidence, as shown for year 2015 in Table 2.