The Estimated Lifetime Medical Cost of Chlamydia, Gonorrhea, and Trichomoniasis in the United States, 2018

The Impacts and Consequences of Sexually Transmitted Infections in the United States

ABSTRACT

Millions of people in the United States are affected by sexually transmitted infections (STIs) every year, with profound consequences for the individual, their community, and society at large. In this review, we aim to summarize the epidemiology of 4 STIs: Chlamydia trachomatis, Neisseria gonorrhoeae, Treponema pallidum, and herpes simplex virus, and to highlight the consequences of those infections among individuals and the healthcare system. Untreated N. gonorrhoeae, C. trachomatis, T. pallidum, or herpes simplex virus infection can result in female infertility, stillbirth, premature birth, and low birth weight. As many as 10% of incident HIV infections among men who have sex with men in the United States have been attributed to either N. gonorrhoeae or C. trachomatis infection. In 1 year in the United States, incident C. trachomatis infection resulted in $824 million lifetime medical costs and a loss of 1,541 lifetime quality-adjusted life years (QALYs) among men and 111,872 among women, while incident N. gonorrhoeae infection led to $323 million in lifetime medical costs, and a loss of 386 QALYs among women and 12,112 among men. Incident T. pallidum infection in 1 year resulted in $206 million in medical costs and a loss of 13,349 QALYs among both men and women, while genital herpes led to $107 million in medical costs and a loss of 33,100 QALYs. STI-attributable infertility alone resulted in more than $135 million in direct medical costs. Cumulatively, STIs lead to substantial financial costs to individuals and the health system, as well as long-term reductions in quality of life.

Oral gepotidacin for the treatment of uncomplicated urogenital gonorrhoea (EAGLE-1): a phase 3 randomised, open-label, non-inferiority, multicentre study

BACKGROUND

Gepotidacin, a first-in-class, bactericidal, triazaacenaphthylene antibacterial that inhibits bacterial DNA replication, was shown to be efficacious and well tolerated in the treatment of uncomplicated urinary tract infections. We evaluated the efficacy and safety of gepotidacin for the treatment of uncomplicated urogenital gonorrhoea.

METHODS

EAGLE-1 (NCT04010539) was a phase 3, open-label, sponsor-blinded, multicentre, non-inferiority study evaluating oral gepotidacin (two 3000 mg doses administered 10-12 h apart) compared with 500 mg intramuscular ceftriaxone plus 1 g oral azithromycin for the treatment of gonorrhoea. Eligible participants were aged 12 years and older, had a bodyweight over 45 kg, and had suspected uncomplicated urogenital gonorrhoea (including mucopurulent discharge), a positive laboratory test for Neisseria gonorrhoeae, or both. Participants were randomly allocated in a 1:1 ratio to each treatment group, stratified by sex (original urogenital anatomy at birth) and sexual orientation (men who have sex with men [MSM], men who have sex with women [MSW], and female) in combination, and age group (age <18 years, ≥18 to 65 years, or >65 years). The primary efficacy endpoint was microbiological success, defined as culture-confirmed bacterial eradication of N gonorrhoeae from the urogenital body site at test-of-cure (days 4-8). The non-inferiority margin was prespecified at -10%. The primary outcome was assessed in the microbiological intention-to-treat (micro-ITT) population, all participants randomly allocated to a study treatment who received at least one dose of their study treatment and had confirmed ceftriaxone-susceptible N gonorrhoeae isolated from the baseline culture of their urogenital specimen. The safety population comprised all participants who received one or more doses of any study treatment.

FINDINGS

Between Oct 21, 2019, and Oct 10, 2023, 628 participants were randomly allocated (314 allocated to each treatment group). Overall, 39 (6%) of 628 participants discontinued the study prematurely (20 in the gepotidacin group and 19 in the ceftriaxone plus azithromycin group), with the primary reason being lost to follow-up. The micro-ITT population included 406 participants (202 in the gepotidacin group and 204 in the ceftriaxone plus azithromycin group). Most participants in the micro-ITT population were male (372 [92%] vs 34 [8%] female), and there was a higher percentage of participants who were MSM (290 [71%]) compared with participants who were MSW (82 [20%]). Participants were predominantly White (299 [74%]) or Black or African American (61 [15%]), with 70 (17%) identifying as Hispanic or Latino. Results of the primary analysis of microbiological response at test-of-cure demonstrated microbiological success rates of 92·6% (187 of 202 [95% CI 88·0 to 95·8]) in the gepotidacin group and 91·2% (186 of 204 [86·4 to 94·7]) in the ceftriaxone plus azithromycin group (adjusted treatment difference -0·1% [95% CI -5·6 to 5·5]). Gepotidacin was non-inferior to ceftriaxone plus azithromycin. No bacterial persistence of urogenital N gonorrhoeae was observed at test-of-cure for either group. The gepotidacin group had higher rates of adverse events and drug-related adverse events, mainly due to gastrointestinal adverse events, and almost all were mild or moderate. No treatment-related severe or serious adverse events occurred in either group.

INTERPRETATION

Gepotidacin demonstrated non-inferiority to ceftriaxone plus azithromycin for urogenital N gonorrhoeae, with no new safety concerns, offering a novel oral treatment option for uncomplicated urogenital gonorrhoea.

FUNDING

GSK and federal funds from the Office of the Assistant Secretary for Preparedness and Response, Biomedical Advanced Research and Development Authority.

Characteristics associated with the adoption of consumer-based -self-sampling methods for sexually transmitted infection screening

Objective: To identify theory-based innovation characteristics associated with the adoption of consumer-based self-sampling methods for sexually transmitted infection screening. Participants: Guided by the Diffusion of Innovation, survey data from people assigned female at birth (AFAB) (n = 92) were analyzed. Methods: Forward regression models and a path analysis were used to predict adoption by characteristics, using maximum likelihood estimation. Measures included acceptability, comfort, addresses healthcare needs, willingness to adopt self-sampling methods, and innovation characteristics. Results: Predictors of willingness to adopt were no clinic visit (relative advantage), convenient pick-up (relative advantage), and low cost. Variables with direct effects on adoption included: addresses healthcare needs, comfort, acceptability, and no clinic visit. Conclusions: Relative advantage was a salient factor and prioritizing this construct in intervention development may facilitate adoption. Results can guide the development of an innovative, theory-based intervention that promotes adoption of self-sampling methods, ultimately improving STI screening rates.

Estimates of the Lifetime Productivity Costs of Chlamydia, Gonorrhea, and Syphilis in the United States

BACKGROUND

Productivity costs of sexually transmitted infections (STIs) reflect the value of lost time due to STI morbidity and mortality, including time spent traveling to, waiting for, and receiving STI treatment. The purpose of this study was to provide updated estimates of the average lifetime productivity cost for chlamydia, gonorrhea, and syphilis, per incident infection.

METHODS

We adapted published decision tree models from recent studies of the lifetime medical costs of chlamydia, gonorrhea, and syphilis in the United States. For each possible outcome of infection, we applied productivity costs that we obtained based on published health economic studies. Productivity costs included the value of patient time spent to receive treatment for STIs and for related sequelae such as pelvic inflammatory disease in women. We used a human capital approach and included losses in market (paid) and nonmarket (unpaid) productivity. We conducted 1-way sensitivity analyses and probabilistic sensitivity analyses.

RESULTS

The average lifetime productivity cost per infection was $28 for chlamydia in men, $205 for chlamydia in women, $37 for gonorrhea in men, $212 for gonorrhea in women, and $411 for syphilis regardless of sex, in 2023 US dollars. The estimated lifetime productivity cost of these STIs acquired in the United States in 2018 was $795 million.

CONCLUSIONS

These estimates of the lifetime productivity costs can help in quantifying the overall economic burden of STIs in the United States beyond just the medical cost burden and can inform cost-effectiveness analyses of STI prevention activities.

Testing trends and co-testing patterns for HIV, hepatitis C and sexually transmitted infections (STIs) in Emergency departments

Background

Many underserved populations use Emergency Department (EDs) as primary sources of care, representing an important opportunity to provide infectious disease testing and linkage to care. We explored national ED testing trends and co-testing patterns for HIV, hepatitis C, and sexually transmitted infections (STIs).

Methods

We used 2010-2019 Healthcare Cost and Utilization Project, Nationwide Emergency Department Sample data to estimate ED visit testing rates for HIV, hepatitis C, chlamydia, gonorrhea, and syphilis infections, identified by Current Procedural Terminology codes. Trends and co-testing (visit with tests for > 1 infection) patterns were analyzed by sociodemographic, hospital, and visit characteristics. Trends were evaluated as the average annual percentage change (AAPC) using the Joinpoint Regression.

Results

During 2010-2019, testing events per 1000 visits (AAPCs) increased for HIV from 1.3 to 4.2 (16.3 %), hepatitis C from 0.4 to 2.2 (25.1 %), chlamydia from 9.1 to 16.0 (6.6 %), gonorrhea from 8.4 to 15.7 (7.4 %), and syphilis from 0.7 to 2.0 (12.9 %). Rate increases varied by several characteristics across infections. The largest AAPC increases were among visits by groups with lower base rate testing in 2010, including persons aged ≥ 65 years (HIV: 36.4 %), with Medicaid (HIV: 43.8 %), in the lowest income quintile (hepatitis C: 36.9 %), living in the West (syphilis: 49.4 %) and with non-emergency diagnoses (hepatitis C: 44.1 %). Co-testing increased significantly for all infections except hepatitis C.

Conclusions

HIV, hepatitis C, and STI testing increased in EDs during 2010-2019; however, co-testing patterns were inconsistent. Co-testing may improve diagnosis and linkage to care, especially in areas experiencing higher rates of infection.

Vaccination May Be Economically and Epidemiologically Advantageous Over Frequent Screening for Gonorrhea Prevention

BACKGROUND

Gonorrhea's rapid development of antimicrobial resistance underscores the importance of new prevention modalities. Recent evidence suggests that a serogroup B meningococcal vaccine may be partially effective against gonococcal infection. However, the viability of vaccination and the role it should play in gonorrhea prevention are an open question.

METHODS

We modeled the transmission of gonorrhea over a 10-year period in a heterosexual population to find optimal patterns of year-over-year investment of a fixed budget in vaccination and screening programs. Each year, resources could be allocated to vaccinating people or enrolling them in a quarterly screening program. Stratifying by mode (vaccination vs. screening), sex (male vs. female), and enrollment venue (background screening vs. symptomatic visit), we consider 8 different ways of controlling gonorrhea. We then found the year-over-year pattern of investment among those 8 controls that most reduced the incidence of gonorrhea under different assumptions. A compartmental transmission model was parameterized from existing literature in the US context.

RESULTS

Vaccinating men with recent symptomatic infection, which selected for higher sexual activity, was optimal for population-level gonorrhea control. Given a prevention budget of $3 per capita, 9.5% of infections could be averted ($299 per infection averted), decreasing gonorrhea sequelae and associated antimicrobial use by similar percentages. These results were consistent across sensitivity analyses that increased the budget, prioritized incidence or prevalence reductions in women, or lowered screening costs. Under a scenario where only screening was implemented, just 5.5% of infections were averted.

CONCLUSIONS

A currently available vaccine, although only modestly effective, may be superior to frequent testing for population-level gonorrhea control.

An Interactive Modeling Tool for Projecting the Health and Direct Medical Cost Impact of Changes in the Sexually Transmitted Diseases Prevention Program Budgets

CONTEXT

Estimating the return on investment for public health services, tailored to the state level, is critical for demonstrating their value and making resource allocation decisions. However, many health departments have limited staff capacity and expertise to conduct economic analyses in-house.

PROGRAM

We developed a user-friendly, interactive Excel-based spreadsheet model that health departments can use to estimate the impact of increases or decreases in sexually transmitted infection (STI) prevention funding on the incidence and direct medical costs of chlamydia, gonorrhea, syphilis, and STI-attributable HIV infections. Users tailor results to their jurisdictions by entering the size of their population served; the number of annual STI diagnoses; their prior annual funding amount; and their anticipated new funding amount. The interface was developed using human-centered design principles, including focus groups with 15 model users to collect feedback on an earlier model version and a usability study on the prototype with 6 model users to finalize the interface.

IMPLEMENTATION

The STI Prevention Allocation Consequences Estimator ("SPACE Monkey 2.0") model will be publicly available as a free downloadable tool.

EVALUATION

In the usability testing of the prototype, participants provided overall positive feedback. They appreciated the clear interpretations, outcomes expressed as direct medical costs, functionalities to interact with the output and copy charts into external applications, visualization designs, and accessible information about the model's assumptions and limitations. Participants provided positive responses to a 10-item usability evaluation survey regarding their experiences with the prototype.

DISCUSSION

Modeling tools that synthesize literature-based estimates and are developed with human-centered design principles have the potential to make evidence-based estimates of budget changes widely accessible to health departments.

Restriction and evasion: a review of IFNγ-mediated cell-autonomous defense pathways during genital Chlamydia infection

Chlamydia trachomatis is the most common cause of bacterial sexually transmitted infection (STI) in the USA. As an STI, C. trachomatis infections can cause inflammatory damage to the female reproductive tract and downstream sequelae including infertility. No vaccine currently exists to C. trachomatis, which evades sterilizing immune responses in its human host. A better understanding of this evasion will greatly benefit the production of anti-Chlamydia therapeutics and vaccination strategies. This minireview will discuss a single branch of the immune system, which activates in response to genital Chlamydia infection: so-called "cell-autonomous immunity" activated by the cytokine interferon-gamma. We will also discuss the mechanisms by which human and mouse-adapted Chlamydia species evade cell-autonomous immune responses in their native hosts. This minireview will examine five pathways of host defense and their evasion: (i) depletion of tryptophan and other nutrients, (ii) immunity-related GTPase-mediated defense, (iii) production of nitric oxide, (iv) IFNγ-induced cell death, and (v) RNF213-mediated destruction of inclusions.

The Past, Present, and Future in the Diagnosis of a Neglected Sexually Transmitted Infection: Trichomoniasis

More than one million curable sexually transmitted infections occur every day. Trichomonas vaginalis is one of the main infections responsible for these epidemiological data; however, the diagnosis of this protozoan is still mainly based on microscopic and culture identification. The commercialization of immunological tests and the development of molecular techniques have improved the sensitivity of classical methods. Nevertheless, the fact that trichomoniasis is a neglected parasitic infection hinders the development of novel techniques and their implementation in routine diagnosis. This review article shows the different methods developed to identify T. vaginalis in population and the difficulties in diagnosing male and asymptomatic patients. The importance of including this parasite in routine gynecological screening, especially in pregnant women, and the importance of considering T. vaginalis as an indicator of high-risk sexual behavior are also discussed.

Advances in Diagnostics of Sexually Transmitted Infections

Sexually transmitted infections (STIs) are caused by various pathogens, many of which have common symptoms. Diagnostic tests are critical to supporting clinical evaluations in making patient management decisions. Molecular diagnostics are the preferred test type when available, especially in asymptomatic patients for many STIs. However, for some infections, serology offers the best insight into infectious status. Clinicians should be aware of the performance characteristics of the available STI diagnostic tests and understand how to use them. Point-of-care tests are helpful to implement rapid and accurate treatment responses, which are particularly helpful in certain at-risk populations.

Chlamydial and gonorrheal neglected sexually transmitted diseases among Pacific Islanders of the Western Pacific Region-A narrative review and call to action

The Pacific Island countries of the Western Pacific Region have some of the highest rates of sexually transmitted Chlamydia trachomatis and Neisseria gonorrhoeae infections in the world. Despite this, there are few research studies that include Pacific Islanders. We conducted a narrative review of original research and surveys, including World Health Organization and Pacific Community reports, to determine the prevalence, management, and treatment of C. trachomatis and N. gonorrhoeae compared to HIV and syphilis from 1980 to 2022. Available epidemiologic data on C. trachomatis and N. gonorrhoeae indicated an extremely high prevalence-approximately 30% and 13%, respectively-among Pacific Islanders during this timeframe. These neglected sexually transmitted infections represent a significant burden and health disparity. Robust epidemiologic research is needed to identify modifiable risk factors for designing interventions and control strategies. Appropriate policies along with regional and international advocacy and aid are required to improve reproductive health among these vulnerable, understudied populations to avert preventable infections and sequelae.

Trends in sexually transmitted infection screening during COVID-19 and missed cases among adolescents

OBJECTIVE

The COVID-19 pandemic disrupted sexual health services for young people, with potential consequences of decreasing preventive screening and increasing undiagnosed sexually transmitted infections (STIs). This study aimed to assess trends in asymptomatic screening among patients receiving STI testing and to estimate the number of STI cases that were missed during the early months of the pandemic.

STUDY DESIGN

A cross-sectional study of electronic health records for chlamydia, gonorrhea, and trichomonas testing encounters from six pediatric primary care clinics in Philadelphia, July 2014 to November 2020.

METHODS

A total of 35,548 testing encounters were analyzed, including 2958 during the pandemic. We assessed whether testing at each encounter was performed as asymptomatic screening, risk-based testing, or symptomatic testing. We evaluated screening trends over time and estimated the number of missed STI cases during the pandemic.

RESULTS

The mean monthly testing encounters decreased from 479 per month prepandemic to 329 per month during the pandemic. The percent of tests performed as asymptomatic screening dropped from 72.5% prepandemic to a nadir of 54.5% in April 2020. We estimate that this decrease in asymptomatic screening would represent 159 missed cases (23.8% of expected cases) based on patient volume from the previous year.

CONCLUSIONS

During the pandemic, the total volume of STI testing encounters and the proportion of tests performed as asymptomatic screening decreased, potentially resulting in missed diagnoses. Undiagnosed STIs can result in severe sequelae and contribute to community transmission of STIs. Efforts are needed to re-establish and sustain access to STI services for adolescents in response to disruptions caused by the pandemic.

Estimated costs and quality-adjusted life-years lost due to N. gonorrhoeae infections acquired in 2015 in the United States: A modelling study of overall burden and disparities by age, race/ethnicity, and other factors

Background

Disparities in the health and economic burden of gonorrhoea have not been systematically quantified. We estimated population-level health losses and costs associated with gonococcal infection and sequelae in the United States.

Methods

We used probability-tree models to capture gonorrhoea sequelae and to estimate attributable disease burden in terms of the discounted lifetime costs and quality-adjusted life-years (QALYs) lost due to incident infections acquired during 2015 from the healthcare system perspective. Numbers of infections in 2015 were obtained from a published gonorrhoea transmission model. We evaluated population-level disease burden, disaggregated by sex, age, race/ethnicity, and for men who have sex with men (MSM). We conducted a multivariate sensitivity analysis for key parameters.

Findings

Discounted lifetime QALYs lost per incident gonococcal infection were estimated as 0.093 (95% uncertainty interval [UI] 0.022-0.22) for women, 0.0020 (0.0015-0.0024) for heterosexual men, and 0.0015 (0.00070-0.0021) for MSM. Discounted lifetime costs per incident infection were USD 261 (109-480), 169 (88-263), and 133 (50-239), respectively. At the population level, total discounted lifetime QALYs lost due to infections acquired during 2015 were 53,293 (12,326-125,366) for women, 621 (430-872) for heterosexual men, and 1,078 (427-1,870) for MSM. Total discounted lifetime costs were USD 150 million (64-277 million), 54 million (25-92 million), and 97 million (34-197 million), respectively. The highest total burden of both QALYs and costs at the population-level was observed in Non-Hispanic Black women, and highest burden per 1,000 person-years was identified in MSM among men and American Indian/Alaska Native among women.

Interpretation

Gonorrhoea causes substantial health losses and costs in the United States. These results can inform planning and prioritization of prevention services.

Funding

Centers for Disease Control and Prevention, Charles A. King Trust.

Evaluating the impact and cost-effectiveness of chlamydia management strategies in Hong Kong: A modeling study

Objectives

To illustrate the epidemiologic and cost-effectiveness impact of shifting the focus from population-based screening toward a targeted management approach for genital chlamydia infection.

Design

Modeling study, implementing an individual-based, stochastic, dynamic network model.

Setting

Hong Kong.

Population

A hypothetical sample network of 10,000 people with a partnership distribution based on Hong Kong's sexually active population of reproductive age (age 18–49 years).

Interventions

In this study, we present several scenarios with different implementations of universal vs. targeted screening (based on partner numbers). We also explored the impact of (1) screening only, (2) screening plus expedited partner therapy, and (3) screening plus partner testing.

Primary outcome measures

Change of chlamydia prevalence before and after implementing the different strategies. The cost-effectiveness analysis reports total direct cost from a health provider perspective, the QALYs gained, and incremental cost-effectiveness ratios (ICER).

Results

In comparing the effects of universal screening only and targeted screening of the high-risk population, the mean prevalence during the 10th year of intervention was 2.75 ± 0.30% and 2.35 ± 0.21%, respectively (compared with 3.24 ± 0.30% and 3.35 ± 0.21% before the interventions, respectively). The addition of contact tracing to the latter targeted screening scenario reduces the mean prevalence during the 10th year of intervention to 1.48 ± 0.13% (compared with 3.31 ± 0.33% at baseline) in the best-case of testing before treatment and maximal contact-tracing effectiveness (40%). Overall, the most effective scenarios were those for which interventions focused on the high-risk population defined by the number of partners, with contact tracing included. The ICER for targeted screening with contact tracing at 20% and 40% efficiency was $4,634 and $7,219 per QALY gained, respectively (10-year time horizon). Expedited partner therapy did not significantly impact overall chlamydia prevalence and caused overtreatment.

Conclusions

Our study suggests that targeted screening with strengthened contact tracing efforts is the most cost-effective strategy to reduce the prevalence of chlamydia in Hong Kong.

Estimating the Association Between Public Health Spending and Sexually Transmitted Disease Rates in the United States: A Systematic Review

ABSTRACT

Public health spending is important for managing increases in sexually transmitted diseases (STDs) in the United States. Although previous studies suggest that a beneficial link exists between public health spending and changes in STD rates, there have been no systematic reviews synthesizing existing evidence regarding the association for STDs at the population level. The objective of this study was to synthesize evidence from studies that assessed the associations between general and STD-specific public health spending and STD rates. We conducted a systematic review using Ovid-Medline, EMBASE, CINAHL, Cochrane Library, Web of Science, and EconLit for relevant studies that examined the association between public health spending and gonorrhea, syphilis, chlamydia, and chancroid rates following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. A total of 5 articles (2 regarding general public health spending and 3 regarding STD-specific public health spending) met our inclusion criteria. There was a significant decrease in gonorrhea, syphilis, chlamydia, and chancroid rates associated with increased public health spending. We also found that STD-specific public health spending has a greater effect on STD rates compared with general public health spending. Our review provides evidence that increases in general and STD-specific public health spending are associated with a reduction of STD rates. Such research regarding estimates of the impact of STD prevention spending can help policy makers identify priority funding areas and inform health resource allocation decisions.

Validation of a New High-Throughput BD COR System Using the BD CTGCTV2 Assay

This study determined the precision and reproducibility of results for the BD CTGCTV2 (CTGCTV2) assay on the BD COR System (COR). The clinical performance of the CTGCTV2 assay conducted on COR was compared with its performance on the BD MAX System (MAX) for detecting Chlamydia trachomatis, Neisseria gonorrhoeae, or Trichomonas vaginalis. The multiday precision and multisite reproducibility studies were conducted using contrived panels of positive and negative urine and PreservCyt specimens. A total of 433 panel members, generated from remnant clinical specimens, were tested in the clinical comparison study. Each panel member was tested three times on MAX and three times on COR. The results in the same testing group were compared for agreement by target. The cycle threshold scores from MAX and COR were analyzed by paired t-test and Deming regression. The CTGCTV2 assay on COR showed high reproducibility in the multiday and multisite precision analysis. The point estimates of positive percent agreement and negative percent agreement in the clinical comparison study for all three targets were greater than 95%, with all corresponding lower bounds of two-sided 95% CIs greater than 90%. Cycle threshold score comparison showed no systematic difference between the two systems. The results of this study show equivalent performance of the CTGCTV2 assay on the MAX and COR systems.

Pelvic inflammatory disease in the adolescent and young adult: An update

Pelvic inflammatory disease (PID) is an infection of the female upper genital tract that is typically polymicrobial with classic core involvement of Neisseria gonorrhoeae and/or Chlamydia trachomatis, though other endogenous flora from the vagino-cervical areas can be involved as well. It is often a sexually transmitted disease but other etiologic routes are also noted. A variety of risk factors have been identified including adolescence, young adulthood, adolescent cervical ectropion, multiple sexual partners, immature immune system, history of previous PID, risky contraceptive practices and others. An early diagnosis and prompt treatment are necessary to reduce risks of PID complications such as chronic pelvic pain, ectopic pregnancy and infertility. Current management principles of PID are also reviewed. It is important for clinicians to screen sexually active females for common sexually transmitted infections such as Chlamydia trachomatis and provide safer sex education to their adolescent and young adult patients. Clinicians should provide comprehensive management to persons with PID and utilize established guidelines such as those from the US Centers for Disease Control and Prevention (CDC).

The Estimated Direct Lifetime Medical Costs of Sexually Transmitted Infections Acquired in the United States in 2018

BACKGROUND

We estimated the lifetime medical costs attributable to sexually transmitted infections (STIs) acquired in 2018, including sexually acquired human immunodeficiency virus (HIV).

METHODS

We estimated the lifetime medical costs of infections acquired in 2018 in the United States for 8 STIs: chlamydia, gonorrhea, trichomoniasis, syphilis, genital herpes, human papillomavirus (HPV), hepatitis B, and HIV. We limited our analysis to lifetime medical costs incurred for treatment of STIs and for treatment of related sequelae; we did not include other costs, such as STI prevention. For each STI, except HPV, we calculated the lifetime medical cost by multiplying the estimated number of incident infections in 2018 by the estimated lifetime cost per infection. For HPV, we calculated the lifetime cost based on the projected lifetime incidence of health outcomes attributed to HPV infections acquired in 2018. Future costs were discounted at 3% annually.

RESULTS

Incident STIs in 2018 imposed an estimated $15.9 billion (25th-75th percentile: $14.9-16.9 billion) in discounted, lifetime direct medical costs (2019 US dollars). Most of this cost was due to sexually acquired HIV ($13.7 billion) and HPV ($0.8 billion). STIs in women accounted for about one fourth of the cost of incident STIs when including HIV, but about three fourths when excluding HIV. STIs among 15- to 24-year-olds accounted for $4.2 billion (26%) of the cost of incident STIs.

CONCLUSIONS

Incident STIs continue to impose a considerable lifetime medical cost burden in the United States. These results can inform health economic analyses to promote the use of cost-effective STI prevention interventions to reduce this burden.

Incidence and Prevalence of Trichomonas vaginalis Infection Among Persons Aged 15 to 59 Years: United States, 2018

BACKGROUND

Trichomonas vaginalis (TV) is a sexually transmitted parasite associated with multiple adverse outcomes in women. Estimating TV incidence is challenging because of its largely asymptomatic presentation.

METHODS

Per-capita prevalence was estimated using the National Health and Nutrition Examination Survey, 2013 to 2018. Incidence was estimated using ordinary differential equations assuming static incidence at steady state and fit using Bayesian techniques. Model inputs included estimates of proportion of asymptomatic cases, natural clearance, and time to symptomatic treatment seeking. Posterior distributions were drawn, and uncertainty was reported, from 25th (Q1) to 75th (Q3) percentiles. Aggregated measures were estimated by combining component distributions.

RESULTS

Among 15- to 59-year-olds in 2018, the number of prevalent TV infections was 2.6 (Q1, 2.4; Q3, 2.7) million overall, 470,000 (Q1, 414,000; Q3, 530,000) among men, and 2.1 (Q1, 2.0; Q3, 2.2) million among women; the numbers of incident infections were 6.9 (Q1, 6.2; Q3, 7.6) million, 3.3 (Q1, 2.8; Q3, 3.8) million, and 3.5 (Q1, 3.1; Q3, 4.0) million among all persons, men, and women, respectively. Persons aged 15 to 24 years comprised 15.6% and 16.3% of all prevalent and incident infections, respectively; prevalence and incidence in both sexes increased with age. Incidences in both sexes were highly dependent on estimates of natural clearance, which were based on few data.

CONCLUSIONS

Prevalence and incidence of TV are substantial in the United States, particularly among those 25 years or older. Although estimated prevalence is higher in women, estimated incidence is similar in men and women. Data on key parameters of TV infection are limited; future research should focus on clarifying the natural history of TV.