Sexually Transmitted Infections Among US Women and Men: Prevalence and Incidence Estimates, 2018.

BACKGROUND: The most recent estimates of the number of prevalent and incident sexually transmitted infections (STIs) in the United States were for 2008. We provide updated estimates for 2018 using new methods. METHODS: We estimated the total number of prevalent and incident infections in the United States for 8 STIs: chlamydia, gonorrhea, trichomoniasis, syphilis, genital herpes, human papillomavirus, sexually transmitted hepatitis B, and sexually transmitted HIV. Updated per-capita prevalence and incidence estimates for each STI were multiplied by the 2018 full resident population estimates to calculate the number of prevalent and incident infections. STI-specific estimates were combined to generate estimates of the total number of prevalent and incident STIs overall, and by sex and age group. Primary estimates are represented by medians, and uncertainty intervals are represented by the 25th (Q1) and 75th (Q3) percentiles of the empirical frequency distributions of prevalence and incidence for each STI. RESULTS: In 2018, there were an estimated 67.6 (Q1, 66.6; Q3, 68.7) million prevalent and 26.2 (Q1, 24.0; Q3, 28.7) million incident STIs in the United States. Chlamydia, trichomoniasis, genital herpes, and human papillomavirus comprised 97.6% of all prevalent and 93.1% of all incident STIs. Persons aged 15 to 24 years comprised 18.6% (12.6 million) of all prevalent infections; however, they comprised 45.5% (11.9 million) of all incident infections. CONCLUSIONS: The burden of STIs in the United States is high. Almost half of incident STIs occurred in persons aged 15 to 24 years in 2018. Focusing on this population should be considered essential for national STI prevention efforts.

Genital Mycoplasma, Shigellosis, Zika, Pubic Lice, and Other Sexually Transmitted Infections: Neither Gone Nor Forgotten.

ABSTRACT: Most estimates of the combined burden and cost of sexually transmitted infections (STIs) in the United States have focused on 8 common STIs with established national surveillance strategies (chlamydia, gonorrhea, syphilis, trichomoniasis, genital herpes, human papillomavirus, and sexually transmitted human immunodeficiency virus and hepatitis B). However, over 30 STIs are primarily sexually transmitted or sexually transmissible. In this article, we review what is known about the burden of "other STIs" in the United States, including those where sexual transmission is not the primary transmission route of infection. Although the combined burden of these other STIs may be substantial, accurately estimating their burden due to sexual transmission is difficult due to diagnostic and surveillance challenges. Developing better estimates will require innovative strategies, such as leveraging existing surveillance systems, partnering with public health and academic researchers outside of the STI field, and developing methodology to estimate the frequency of sexual transmission, particularly for new and emerging STIs.

The Influence of Screening, Misclassification, and Reporting Biases on Reported Chlamydia Case Rates Among Young Women in the United States, 2000 Through 2017.

BACKGROUND: National chlamydia case rate trends are difficult to interpret because of biases from partial screening coverage, imperfect diagnostic tests, and underreporting. We examined the extent to which these time-varying biases could influence reported annual chlamydia case rates. METHODS: Annual reported case rates among women aged 15 through 24 years from 2000 through 2017 were obtained from the Centers for Disease Control and Prevention's National Center for HIV/AIDS, Viral Hepatitis, STD, and TB Prevention AtlasPlus tool. Estimates of reporting completeness, diagnostic test sensitivity and specificity, and screening coverage were derived from literature review and expert opinion. We adjusted annual reported case rates for incomplete reporting, imperfect diagnostic tests, and partial screening coverage through a series of corrections, and calculated annual adjusted case rates of correctly diagnosed chlamydia. RESULTS: Adjusted chlamydia case rates among young women were higher than reported case rates throughout the study period. Reported case rates increased over the study period, but adjusted rates declined from 12,900 to 7900 cases per 100,000 person-years between 2000 and 2007. After 2007, adjusted case rates declined to 7500 cases per 100,000 person-years in 2017. Bias from partial screening coverage had a larger impact on case rate magnitude and trend shape than bias from imperfect diagnostic tests or underreporting. CONCLUSIONS: Reported chlamydia case rates may be substantially lower than true chlamydia case rates because of incomplete reporting, imperfect diagnostic tests, and partial screening coverage. Because the magnitude of these biases has declined over time, the differences between reported and adjusted case rates have narrowed, revealing a sharp decline in adjusted case rates even as reported case rates have risen. The decline in adjusted case rates suggests that the rise in reported case rates should not be interpreted strictly as increasing chlamydia incidence, as the observed rise can be explained by improvements in screening coverage, diagnostic tests, and reporting.

Temporal Patterns in Chlamydia Repeat Testing in Massachusetts.

INTRODUCTION: National guidelines recommend test-of-cure for pregnant women and test-of-reinfection for all patients with chlamydia infections in order to interrupt transmission and prevent adverse sequelae for patients, partners, and newborns. Little is known about retesting and positivity rates, and whether they are changing over time, particularly in private sector practices. METHODS: Electronic health record data on patients with chlamydia tests were extracted from three independent clinical practice groups serving ≅20% of the Massachusetts population. Records were extracted using the Electronic medical record Support for Public Health platform (esphealth.org). These data were analyzed for temporal trends in annual repeat testing rates by using generalized estimating equations after index positive chlamydia tests between 2010 and 2015 and for differences in intervals to first repeat tests among pregnant females, non-pregnant females, and males. Data extraction and analysis were performed during calendar years 2017 and 2018. RESULTS: An index positive C. trachomatis result was identified for 972 pregnant female cases, 10,309 non-pregnant female cases, and 4,973 male cases. Test-of-cure 3-5 weeks after an index positive test occurred in 37% of pregnant females. Test-of-reinfection 8-16 weeks after an index positive test occurred in 39% of pregnant females, 18% of non-pregnant females, and 9% of males. There were no significant increases in test-of-cure or test-of-reinfection rates from 2010 to 2015. Among cases with repeat tests, 16% of pregnant females, 15% of non-pregnant females, and 16% of males had positive results. CONCLUSIONS: Chlamydia test-of-cure and test-of-reinfection rates are low, with no evidence of improvement over time. There are substantial opportunities to improve adherence to chlamydia repeat testing recommendations.

Increased Methamphetamine, Injection Drug, and Heroin Use Among Women and Heterosexual Men with Primary and Secondary Syphilis - United States, 2013-2017.

During 2013-2017, the national annual rate of reported primary and secondary (P&S) syphilis cases in the United States increased 72.7%, from 5.5 to 9.5 cases per 100,000 population (1). The highest rates of P&S syphilis are seen among gay, bisexual, and other men who have sex with men (collectively referred to as MSM) (2), and MSM continued to account for the majority of cases in 2017 (1). However, during 2013-2017, the P&S syphilis rate among women increased 155.6% (from 0.9 to 2.3 cases per 100,000 women), and the rate among all men increased 65.7% (from 10.2 to 16.9 cases per 100,000 men), indicating increasing transmission between men and women in addition to increasing transmission between men (1). To further understand these trends, CDC analyzed national P&S syphilis surveillance data for 2013-2017 and assessed the percentage of cases among women, men who have sex with women only (MSW), and MSM who reported drug-related risk behaviors during the past 12 months. Among women and MSW with P&S syphilis, reported use of methamphetamine, injection drugs, and heroin more than doubled during 2013-2017. In 2017, 16.6% of women with P&S syphilis used methamphetamine, 10.5% used injection drugs, and 5.8% used heroin during the preceding 12 months. Similar trends were seen among MSW, but not among MSM. These findings indicate that a substantial percentage of heterosexual syphilis transmission is occurring among persons who use these drugs, particularly methamphetamine. Collaboration between sexually transmitted disease (STD) control programs and partners that provide substance use disorder services will be important to address recent increases in heterosexual syphilis.

Trends in the Prevalence of Anogenital Warts Among Patients at Sexually Transmitted Disease Clinics-Sexually Transmitted Disease Surveillance Network, United States, 2010-2016.

BACKGROUND: Approximately 90% of genital warts are caused by human papillomavirus (HPV) types 6 and 11. In the United States, HPV vaccination has been recommended for girls and women aged ≤26 years, and since 2011, for boys and men aged ≤21 years and for gay, bisexual, and other men who have sex with men (MSM) aged ≤26 years. METHODS: Data were obtained from 27 clinics participating in the STD Surveillance Network. Trends in the annual prevalence of anogenital warts (AGW) from 2010-2016 were described by sex and by the sex of sex partners. RESULTS: During 2010-2016, significant declines in the prevalence of AGW were observed in women aged <40 years, men who have sex with women only (MSW) aged <40 years, and MSM of all age categories. An inflection in trend in 2012 was noted for MSW aged 20-24 or 25-29 years and for MSM aged 20-24 years. CONCLUSIONS: The observed declines in the prevalence of AGW suggest that HPV morbidity is declining among populations attending STD clinics, including MSW, MSM, and women. Declines in younger age groups are consistent with what would be expected following the implementation of HPV vaccination. However, declines were also observed in older age groups and are not likely to be the result of vaccination.

Prevalence of sexually transmitted infections and bacterial vaginosis among women in sub-Saharan Africa: An individual participant data meta-analysis of 18 HIV prevention studies.

BACKGROUND: Estimates of sexually transmitted infection (STI) prevalence are essential for efforts to prevent and control STIs. Few large STI prevalence studies exist, especially for low- and middle-income countries (LMICs). Our primary objective was to estimate the prevalence of chlamydia, gonorrhea, trichomoniasis, syphilis, herpes simplex virus type 2 (HSV-2), and bacterial vaginosis (BV) among women in sub-Saharan Africa by age, region, and population type. METHODS AND FINDINGS: We analyzed individual-level data from 18 HIV prevention studies (cohort studies and randomized controlled trials; conducted during 1993-2011), representing >37,000 women, that tested participants for ≥1 selected STIs or BV at baseline. We used a 2-stage meta-analysis to combine data. After calculating the proportion of participants with each infection and standard error by study, we used a random-effects model to obtain a summary mean prevalence of each infection and 95% confidence interval (CI) across ages, regions, and population types. Despite substantial study heterogeneity for some STIs/populations, several patterns emerged. Across the three primary region/population groups (South Africa community-based, Southern/Eastern Africa community-based, and Eastern Africa higher-risk), prevalence was higher among 15-24-year-old than 25-49-year-old women for all STIs except HSV-2. In general, higher-risk populations had greater prevalence of gonorrhea and syphilis than clinic/community-based populations. For chlamydia, prevalence among 15-24-year-olds was 10.3% (95% CI: 7.4%, 14.1%; I2 = 75.7%) among women specifically recruited from higher-risk settings for HIV in Eastern Africa and was 15.1% (95% CI: 12.7%, 17.8%; I2 = 82.3%) in South African clinic/community-based populations. Among clinic/community-based populations, prevalence was generally greater in South Africa than in Southern/Eastern Africa for most STIs; for gonorrhea, prevalence among 15-24-year-olds was 4.6% (95% CI: 3.3%, 6.4%; I2 = 82.8%) in South Africa and was 1.7% (95% CI: 1.2%, 2.6%; I2 = 55.2%) in Southern/Eastern Africa. Across the three primary region/population groups, HSV-2 and BV prevalence was high among 25-49-year-olds (ranging from 70% to 83% and 33% to 44%, respectively). The main study limitation is that the data are not from random samples of the target populations. CONCLUSIONS: Combining data from 18 HIV prevention studies, our findings highlight important features of STI/BV epidemiology among sub-Saharan African women. This methodology can be used where routine STI surveillance is limited and offers a new approach to obtaining critical information on STI and BV prevalence in LMICs.

Chlamydia Prevalence Trends Among Women and Men Entering the National Job Training Program From 1990 Through 2012.

BACKGROUND: Evaluating chlamydia prevalence trends from sentinel surveillance is important for understanding population disease burden over time. However, prevalence trend estimates from surveillance data may be misleading if they do not account for changes in risk profiles of individuals who are screened (case mix) and changing performance of the screening tests used. METHODS: We analyzed chlamydia screening data from a sentinel surveillance population of 389,555 young women (1990-2012) and 303,699 young men (2003-2012) entering the US National Job Training Program. This period follows the introduction of national chlamydia screening programs designed to prevent transmission and reduce population disease burden. After ruling out bias due to case mix, we used an expectation-maximization-based maximum likelihood approach to account for measurement error from changing screening tests, and generated minimally biased long-term chlamydia prevalence trend estimates among youth and young adults in this sentinel surveillance population. RESULTS: Adjusted chlamydia prevalence among women was high throughout the study period, but fell from 20% in 1990 to 12% in 2003, and remained between 12% and 14% through 2012. Adjusted prevalence among men was steady throughout the study period at approximately 7%. For both women and men, adjusted prevalence was highest among Black and American Indian youth and young adults, and in the Southern and Midwestern regions of the United States throughout the study period. CONCLUSIONS: Our minimally biased trend estimates provide support for an initial decrease in chlamydia prevalence among women soon after the introduction of national chlamydia screening programs. Constant chlamydia prevalence in more recent years suggests that screening may not be sufficient to further reduce chlamydia prevalence among high-risk youth and young adults.

Self-Reported Chlamydia and Gonorrhea Testing and Diagnosis Among Men Who Have Sex With Men-20 US Cities, 2011 and 2014.

BACKGROUND: Annual screening for chlamydia and gonorrhea is recommended for sexually active men who have sex with men (MSM) at anatomical sites of contact, regardless of condom use. METHODS: We assessed differences in self-reported chlamydia and gonorrhea testing and diagnosis in the past 12 months among MSM using National HIV Behavioral Surveillance data from 2011 and 2014. Men who have sex with men who had 1 or more partners in the past 12 months were included in analyses. Analyses of chlamydia and gonorrhea diagnosis data were limited to participants who reported past 12 months chlamydia and gonorrhea testing, respectively. Differences in testing and diagnosis over time were assessed using Poisson regression models with robust standard errors separately for chlamydia and gonorrhea. RESULTS: Analyses included data from 18,896 MSM (2011, n = 9256; 2014, n = 9640). Testing for chlamydia was 37% in 2011 and 47% in 2014 (prevalence ratio [PR], 1.25; 95% confidence interval [CI], 1.20-1.30) and 38% and 47% for gonorrhea (PR, 1.24; 95% CI, 1.19-1.29). Testing was higher in 2014 among most demographic subgroups. Prevalence of chlamydia diagnoses was 8% in 2011 and 11% in 2014 (PR, 1.37; 95% CI, 1.18-1.59) and of gonorrhea diagnoses was 10% in 2011 and 14% in 2014 (adjusted PR: 1.40, 95% CI, 1.23-1.60). Larger changes in diagnoses were observed among MSM in the white and "other" racial categories and those who disclosed same-sex behavior to their health care provider. CONCLUSIONS: Self-reported testing and diagnoses among MSM increased from 2011 to 2014. Increased efforts are needed to meet annual sexually transmitted disease screening recommendations among MSM at high HIV risk.

Declines in Anogenital Warts Among Age Groups Most Likely to Be Impacted by Human Papillomavirus Vaccination, United States, 2006-2014.

OBJECTIVES: To detect decreases in anogenital warts (AGW) among sex and age groups likely to be affected by human papillomavirus vaccination. METHODS: We estimated annual AGW prevalence during 2006 to 2014 using health care claims among US private health insurance enrollees aged 15 to 39 years. We derived AGW diagnoses using 1 of the following: (1) condylomata acuminata diagnosis, (2) viral wart diagnosis combined with a benign anogenital neoplasm diagnosis or destruction or excision of an anogenital lesion, or (3) AGW medication combined with a benign anogenital neoplasm diagnosis or destruction or excision of an anogenital lesion. RESULTS: Prevalence decreased during 2008 to 2014 among females aged 15 to 19 years (annual percentage change [APC] = -14.1%; P < .001) and during 2009 to 2014 among women aged 20 to 24 years (APC = -12.9%; P < .001) and among women aged 25 to 29 years (APC = -6.0%; P = .001). We observed significant declines among men aged 20 to 24 years (APC = -6.5%; P = .005). Prevalence increased or was stable in all other sex and age groups. CONCLUSIONS: We observed AGW decreases among females in the age groups most likely to be affected by human papillomavirus vaccination and decreases in men aged 20 to 24 years. Decreased prevalence in young men is likely attributable to herd protection from vaccination among females.

Gonorrhea Control, United States, 1972-2015, A Narrative Review.

Gonorrhea is the second most commonly reported infection. It can lead to pelvic inflammatory disease, ectopic pregnancy, and infertility. Rates of gonorrhea decreased after the National Gonorrhea Control Program began in 1972, but stabilized in the mid 1990s. The emergence of antimicrobial resistant strains increases the urgency for enhanced gonorrhea control efforts. To identify possible approaches for improving gonorrhea control, we reviewed historic protocols, reports, and other documents related to the activities of the National Gonorrhea Control Program using Centers for Disease Control and Prevention records and the published literature. The Program was a massive effort that annually tested up to 9.3 million women, and treated up to 85,000 infected partners and 100,000 additional exposed partners. Reported gonorrhea rates fell by 74% between 1976 and 1996, then stabilized. Testing positivity was 1.6-4.2% in different settings in 1976. In 1999-2008, the test positivity of a random sample of 14- to 25-year-olds was 0.4%. Gonorrhea testing rates remain high, however, partner notification efforts decreased in the 1990s as attention shifted to human immunodeficiency virus and other sexually transmitted diseases. The decrease and subsequent stabilization of gonorrhea rates was likely also influenced by changes in behavior, such as increases in condom use in response to acquired immune deficiency syndrome. Renewed emphasis on partner treatment might lead to further decreases in rates of gonorrhea.

Ecological Association of Human Papillomavirus Vaccination with Cervical Dysplasia Prevalence in the United States, 2007-2014.

OBJECTIVES: To examine prevalence of low- and high-grade cervical lesions over time in a large cohort of US female adolescents and women. METHODS: We used health care claims data from 9 million privately insured female patients aged 15 to 39 years to estimate annual prevalence of cytologically detected cervical low-grade (LSIL) and high-grade squamous intraepithelial lesions (HSIL) and high-grade histologically detected cervical intraepithelial neoplasia grades 2 and 3 (CIN2+) during 2007 through 2014. We restricted analyses to those who received cervical cancer screening in a given calendar year. RESULTS: Prevalence of HSIL and CIN2+ decreased significantly for those aged 15 to 19 years. Average annual percent change in prevalence in this group during 2007 through 2014 for HSIL and CIN2+ was -8.3% and -14.4%, respectively (P < .001 for both estimates). Prevalence of HSIL and CIN2+ also decreased significantly for women aged 20 to 24 years. No decreases were seen in women aged 25 to 39 years. CONCLUSIONS: Decreases in high-grade lesions reflected their greater association with human papillomavirus types 16 and 18, compared with low-grade lesions, providing ecological evidence of population effectiveness of human papillomavirus vaccination among young, privately insured women.

Estimating chlamydia re-infection rates: an empirical example.

OBJECTIVE: Chlamydia re-infection data are used to inform and evaluate chlamydia control programmes. We quantitatively investigated the effect of denominator selection on estimating re-infection rates and trends. METHODS: Using data on women aged 15-44 years enrolled in Group Health Cooperative (GH), a Pacific Northwest health plan, annual chlamydia re-infection rates from 1998 to 2006 were calculated. Three different denominators were compared using person-years contributed by: (1) all women; (2) women with a prior documented chlamydial infection regardless of whether they were retested; and (3) women with a prior chlamydial infection who were retested within 14 months. RESULTS: From 1998 to 2006, among all women 15-44 years enrolled in GH, re-infection rates increased from 64 to 149 cases per 100 000 person-years. Among women with a prior infection, rates decreased from 10 857 to 8782 cases per 100 000 person-years. Among women with a prior infection who were retested, rates increased from 29 374 to 42 475 cases per 100 000 person-years. CONCLUSIONS: Using the same dataset, we demonstrate that it is possible to tell three different stories about the magnitude of rates and trends in chlamydia re-infection among women by using different denominators. All of these strategies have limitations, but restricting the denominator to women with a prior infection who are retested may best represent the population at-risk for re-infection. Still, rates do not account for additional factors influencing the number of re-infections diagnosed, including screening coverage and changes in test technology. Caution is needed in examining and comparing re-infection data.

Chlamydia trachomatis infection among women 26 to 39 years of age in the United States, 1999 to 2010.

Using data from a nationally representative survey, we identified predictors of chlamydial infection in women aged 26 to 39 years. Chlamydia prevalence was low overall but varied by sociodemographics and sexual behaviors. Findings support current recommendations that women older than 25 years should not be routinely screened for chlamydial infection.

Pregnancy and HIV infection in young women in North Carolina.

OBJECTIVES: We described young women in North Carolina (NC) who were pregnant at the time of diagnosis with human immunodeficiency virus (HIV) infection to identify an at-risk population that could be targeted for increased HIV screening. We investigated the combined effect of partner counseling and referral services (PCRS) and comprehensive prenatal HIV screening. METHODS: We conducted a retrospective review of PCRS charts on young women newly diagnosed with HIV in NC between 2002 and 2005. We determined the prevalence of pregnancy in the study sample and conducted bivariate analyses to assess predictors of pregnancy at the time of HIV diagnosis, calculating prevalence ratios (PRs) with 95% confidence intervals (CIs). We analyzed results of partner notification efforts, including timing and stage of diagnosis of HIV-positive partners. RESULTS: During the four-year period, 551 women aged 18-30 years were newly diagnosed with HIV; 30% were pregnant at the time of HIV diagnosis. Pregnant women were more likely to be Hispanic (PR=1.58, 95% CI 1.15, 2.17) and not report typical risk factors. Fourteen percent of pregnant women's partners had an undiagnosed infection compared with slightly more than 8% of nonpregnant women's partners (p<0.01). CONCLUSIONS: Ethnic differences in co-diagnosis of pregnancy and HIV suggest that young Hispanic women may have differential access to and acceptance of routine HIV screening. Comprehensive prenatal screening combined with partner notification can be effective in reaching infected male partners who are undiagnosed.