Estimates of the Prevalence and Incidence of Chlamydia and Gonorrhea Among US Men and Women, 2018.

BACKGROUND: The most recent prevalence and incidence estimates for chlamydia and gonorrhea, the two most reported nationally notifiable conditions in the United States (US), were for 2008. We present updated estimates for the number of prevalent and incident chlamydial and gonococcal infections for 2018.

METHODS: We estimated chlamydial prevalence directly from the 2015-2018 cycles of the National Health and Nutrition Examination Survey (NHANES) and chlamydial incidence using a mathematical model primarily informed by NHANES and case report data. Total and antimicrobial resistant (AMR) gonococcal prevalence and incidence were estimated using mathematical models primarily informed by case report and Gonococcal Isolate Surveillance Program data. Estimates were calculated for the total population, all women, and all men aged 15-39 years, stratified by age group. Primary estimates represent medians and uncertainty intervals represent the 25th (Q1) and 75th (Q3) percentiles of the empirical frequency distributions of prevalence and incidence for each infection.

RESULTS: Among persons aged 15-39 years in the US in 2018, we estimate 2.35 (Q1=2.20, Q3=2.51) million prevalent and 3.98 (Q1=3.77, Q3=4.22) million incident chlamydial infections, and an estimated 209,000 (Q1=183,000, Q3=241,000) prevalent and 1.57 (Q1=1.44, Q3=1.72) million incident gonococcal infections. Of all gonococcal infections, there were 107,000 (Q1=94,000, Q3=124,000) prevalent and 804,000 (Q1=738,000, Q3=883,000) incident infections demonstrating AMR or elevated minimum inhibitory concentrations (MICs) to selected antibiotics.

CONCLUSIONS: Chlamydia and gonorrhea were very common in the US in 2018. Estimates show that more than 800,000 newly acquired gonococcal infections in 2018 demonstrated resistance or elevated MICs to currently or previously recommended antibiotics.