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.

The Estimated Lifetime Quality-Adjusted Life-Years Lost Due to Chlamydia, Gonorrhea, and Trichomoniasis in the United States in 2018.

BACKGROUND: Comprehensive evaluation of the quality-adjusted life-years (QALYs) lost attributable to chlamydia, gonorrhea, andtrichomoniasis in the United States is lacking. METHODS: We adapted a previous probability-tree model to estimate the average number of lifetime QALYs lost due to genital chlamydia, gonorrhea, and trichomoniasis, per incident infection and at the population level, by sex and age group. We conducted multivariate sensitivity analyses to address uncertainty around key parameter values. RESULTS: The estimated total discounted lifetime QALYs lost for men and women, respectively, due to infections acquired in 2018, were 1541 (95% uncertainty interval [UI], 186-6358) and 111 872 (95% UI, 29 777-267 404) for chlamydia, 989 (95% UI, 127-3720) and 12 112 (95% UI, 2 410-33 895) for gonorrhea, and 386 (95% UI, 30-1851) and 4576 (95% UI, 13-30 355) for trichomoniasis. Total QALYs lost were highest among women aged 15-24 years with chlamydia. QALYs lost estimates were highly sensitive to disutilities (health losses) of infections and sequelae, and to duration of infections and chronic sequelae for chlamydia and gonorrhea in women. CONCLUSIONS: The 3 sexually transmitted infections cause substantial health losses in the United States, particularly gonorrhea and chlamydia among women. The estimates of lifetime QALYs lost per infection help to prioritize prevention policies and inform cost-effectiveness analyses of sexually transmitted infection interventions.

Costs, Health Benefits, and Cost-Effectiveness of Chlamydia Screening and Partner Notification in the United States, 2000-2019: A Mathematical Modeling Analysis.

BACKGROUND: Chlamydia remains a significant public health problem that contributes to adverse reproductive health outcomes. In the United States, sexually active women 24 years and younger are recommended to receive annual screening for chlamydia. In this study, we evaluated the impact of estimated current levels of screening and partner notification (PN), and the impact of screening based on guidelines on chlamydia associated sequelae, quality adjusted life years (QALYs) lost and costs. METHODS: We conducted a cost-effectiveness analysis of chlamydia screening, using a published calibrated pair formation transmission model that estimated trends in chlamydia screening coverage in the United States from 2000 to 2015 consistent with epidemiological data. We used probability trees to translate chlamydial infection outcomes into estimated numbers of chlamydia-associated sequelae, QALYs lost, and health care services costs (in 2020 US dollars). We evaluated the costs and population health benefits of screening and PN in the United States for 2000 to 2015, as compared with no screening and no PN. We also estimated the additional benefits that could be achieved by increasing screening coverage to the levels indicated by the policy recommendations for 2016 to 2019, compared with screening coverage achieved by 2015. RESULTS: Screening and PN from 2000 to 2015 were estimated to have averted 1.3 million (95% uncertainty interval [UI] 490,000-2.3 million) cases of pelvic inflammatory disease, 430,000 (95% UI, 160,000-760,000) cases of chronic pelvic pain, 300,000 (95% UI, 104,000-570,000) cases of tubal factor infertility, and 140,000 (95% UI, 47,000-260,000) cases of ectopic pregnancy in women. We estimated that chlamydia screening and PN cost $9700 per QALY gained compared with no screening and no PN. We estimated the full realization of chlamydia screening guidelines for 2016 to 2019 to cost $30,000 per QALY gained, compared with a scenario in which chlamydia screening coverage was maintained at 2015 levels. DISCUSSION: Chlamydia screening and PN as implemented in the United States from 2000 through 2015 has substantially improved population health and provided good value for money when considering associated health care services costs. Further population health gains are attainable by increasing screening further, at reasonable cost per QALY gained.

Variation in Patterns of Racial and Ethnic Disparities in Primary and Secondary Syphilis Diagnosis Rates Among Heterosexually Active Women by Region and Age Group in the United States.

BACKGROUND: Syphilis rates have increased substantially over the past decade. Women are an important population because of negative sequalae and adverse maternal outcomes including congenital syphilis. We assessed whether racial and ethnic disparities in primary and secondary (P&S) syphilis among heterosexually active women differ by region and age group. METHODS: We synthesized 4 national surveys to estimate numbers of heterosexually active women in the United States from 2014 to 2018 by region, race and ethnicity, and age group (18-24, 25-29, 30-44, and ≥45 years). We calculated annual P&S syphilis diagnosis rates, assessing disparities with rate differences and rate ratios comparing White, Hispanic, and Black heterosexually active women. RESULTS: Nationally, annual rates were 6.42 and 2.20 times as high among Black and Hispanic than among White heterosexually active women (10.99, 3.77, and 1.71 per 100,000, respectively). Younger women experienced a disproportionate burden of P&S syphilis and the highest disparities. Regionally, the Northeast had the highest Black-White and Hispanic-White disparities using a relative disparity measure (relative rate), and the West had the highest disparities using an absolute disparity measure (rate difference). CONCLUSIONS: To meet the racial and ethnic disparity goals of the Sexually Transmitted Infections National Strategic Plan, tailored local interventions that address the social and structural factors associated with disparities are needed for different age groups.

The Estimated Lifetime Medical Cost of Syphilis in the United States.

BACKGROUND: The purpose of this study was to estimate the cost of syphilis in the United States, in terms of the average lifetime direct medical cost per infection. METHODS: We used a decision tree model of the natural history of syphilis. The model allowed for numerous possible outcomes of infection, including treatment for syphilis at various stages, inadvertent treatment, and late syphilis outcomes in those who are alive and still infected 30 years after acquisition. Future costs were discounted at 3% annually. Model inputs, such as the cost and probability of each outcome, were based on published sources. The probabilities we applied yielded outcomes consistent with reported cases of syphilis by stage from national surveillance data and number of deaths due to late syphilis from national mortality data. RESULTS: The estimated, discounted lifetime cost per infection was $1190 under base case assumptions (2019 dollars). Treatment costs associated with late syphilis outcomes, such as cardiovascular syphilis, accounted for only $26 of the average lifetime cost per infection. Results were most sensitive to assumptions regarding the treatment cost per case of unknown duration or late syphilis. In the probabilistic sensitivity analyses, the 2.5th and 97.5th percentiles of the 10,000 simulations of the lifetime cost per infection were $729 and $1884, respectively. CONCLUSIONS: Our estimate of the lifetime cost per infection is about 50% higher than in a previous study, a difference due in large part to our higher cost assumptions for benzathine penicillin G.

The Estimated Number and Lifetime Medical Cost of HIV Infections Attributable to Sexually Transmitted Infections Acquired in the United States in 2018: A Compilation of Published Modeling Results.

BACKGROUND: The purpose of this study was to estimate the number and lifetime medical cost of HIV infections attributable to incident sexually transmitted infections (STIs) in the United States in 2018. METHODS: We combined data from published models regarding the number or percentage of HIV infections attributable to STIs with updated estimates of the lifetime medical cost per HIV infection. We used 2 distinct calculation methods. Our first calculation used recent estimates of the percentage of HIV infections in men who have sex with men (MSM) attributable to gonorrhea and chlamydia. Our second calculation, based on older studies, used estimates of the expected number of STI-attributable HIV infections per new STI infection, for gonorrhea, chlamydia, syphilis, and trichomoniasis. RESULTS: Our first calculation method suggested that 2489 (25th-75th percentiles, 1895-3000) HIV infections in 2018 among MSM could be attributed to gonorrhea and chlamydia, at an estimated lifetime medical cost of $1.05 billion (25th-75th percentiles, $0.79-$1.26 billion). Our second calculation method suggested that 2349 (25th-75th percentiles, 1948-2744) HIV infections in the general population (including MSM) could be attributed to chlamydia, gonorrhea, syphilis, and trichomoniasis acquired in 2018, at an estimated lifetime medical cost of $0.99 billion (25th-75th percentiles, $0.80-$1.16 billion). CONCLUSIONS: Despite ambiguity regarding the degree to which STIs affect HIV transmission, our combination of data from published STI/HIV transmission models and an HIV lifetime medical cost model can help to quantify the estimated burden of STI-attributable HIV infections in the United States.

Lifetime Medical Costs of Genital Herpes in the United States: Estimates From Insurance Claims.

BACKGROUND: The purpose of this study was to estimate the lifetime direct medical costs per incident case of genital herpes in the United States. METHODS: We used medical claims data to construct a cohort of people continuously enrolled in insurance for at least 48 consecutive months between 2010 and 2018. From this cohort, we identified initial genital herpes diagnoses as well as the cost of related clinical visits and medication during the 36 months after an initial diagnosis. Lifetime costs beyond 36 months were estimated based on treatment use patterns observed in the 36 months of follow-up. RESULTS: The present value of lifetime direct medical costs of genital herpes was estimated to be $972 per treated case or $165 per infection (2019 dollars), not including costs associated with prevention or treatment of neonatal herpes. The clinical visit at which genital herpes was first diagnosed accounted for 27% of lifetime costs. Subsequent clinical visits and medications related to genital herpes accounted for an additional 13% and 60% of lifetime costs, respectively. CONCLUSIONS: The results from this study can inform cost-effectiveness analysis of genital herpes control interventions as well as help quantify the cost burden of sexually transmitted infections in the United States.

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

BACKGROUND: The purpose of this study was to provide updated estimates of the average lifetime medical cost per infection for chlamydia, gonorrhea, and trichomoniasis. METHODS: We adapted a published decision tree model that allowed for 7 possible outcomes of infection: (1) symptomatic infection, treated, no sequelae; (2) symptomatic infection, not treated, sequelae; (3) symptomatic infection, not treated, no sequelae; (4) asymptomatic infection, treated, sequelae; (5) asymptomatic infection, treated, no sequelae; (6) asymptomatic infection, not treated, sequelae; and (7) asymptomatic infection, not treated, no sequelae. The base case values and ranges we applied for the model inputs (i.e., the probability and cost assumptions) were based on published studies. RESULTS: The estimated lifetime medical costs per infection for men and women, respectively, were $46 (95% credibility interval, $32-$62) and $262 ($127-$483) for chlamydia, $78 ($36-$145) and $254 ($96-$518) for gonorrhea, and $5 ($1-$14) and $36 ($17-$58) for trichomoniasis. Cost estimates for men were most sensitive to assumptions regarding the probability that the infection is symptomatic, the probability of treatment if asymptomatic, and the cost of treatment of infection. Cost estimates for chlamydia and gonorrhea in women were most sensitive to assumptions regarding the probability and cost of subsequent pelvic inflammatory disease. CONCLUSIONS: These estimates of the lifetime medical cost per infection can inform updated estimates of the total annual cost of sexually transmitted infections in the United States, as well as analyses of the value and cost-effectiveness of sexually transmitted infection prevention interventions.

The Estimated Lifetime Medical Cost of Diseases Attributable to Human Papillomavirus Infections Acquired in 2018.

INTRODUCTION: We estimated the lifetime medical costs of diagnosed cases of diseases attributable to human papillomavirus (HPV) infections acquired in 2018. METHODS: We adapted an existing mathematical model of HPV transmission and associated diseases to estimate the lifetime number of diagnosed cases of disease (genital warts; cervical intraepithelial neoplasia; and cervical, vaginal, vulvar, penile, anal, and oropharyngeal cancers) attributable to HPV infections that were acquired in 2018. For each of these outcomes, we multiplied the estimated number of cases by the estimated lifetime medical cost per case obtained from previous studies. We estimated the costs of recurrent respiratory papillomatosis in a separate calculation. Future costs were discounted at 3% annually. RESULTS: The estimated discounted lifetime medical cost of diseases attributable to HPV infections acquired in 2018 among people aged 15 to 59 years was $774 million (in 2019 US dollars), of which approximately half was accounted for by infections in those aged 15 to 24 years. Human papillomavirus infections in women accounted for approximately 90% of the lifetime number of diagnosed cases of disease and 70% of the lifetime cost attributable to HPV infections acquired in 2018 among those aged 15 to 59 years. CONCLUSIONS: We estimated the lifetime medical costs of diseases attributable to HPV infections acquired in 2018 to be $774 million. This estimate is lower than previous estimates, likely due to the impact of HPV vaccination. The lifetime cost of disease attributable to incident HPV infections is expected to decrease further over time as HPV vaccination coverage increases.

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.

Estimated Prevalence and Incidence of Disease-Associated Human Papillomavirus Types Among 15- to 59-Year-Olds in the United States.

INTRODUCTION: Human papillomavirus (HPV) can cause anogenital warts and several types of cancer, including cervical cancers and precancers. We estimated the prevalence, incidence, and number of persons with prevalent and incident HPV infections in the United States in 2018. METHODS: Prevalence and incidence were estimated for infections with any HPV (any of 37 types detected using Linear Array) and disease-associated HPV, 2 types that cause anogenital warts plus 14 types detected by tests used for cervical cancer screening (HPV 6/11/16/18/31/33/35/39/45/51/52/56/58/59/66/68). We used the 2013-2016 National Health and Nutrition Examination Survey to estimate prevalence among 15- to 59-year-olds, overall and by sex. Incidences in 2018 were estimated per 10,000 persons using an individual-based transmission-dynamic type-specific model calibrated to US data. We estimated number of infected persons by applying prevalences and incidences to 2018 US population estimates. RESULTS: Prevalence of infection with any HPV was 40.0% overall, 41.8% in men, and 38.4% in women; prevalence of infection with disease-associated HPV was 24.2% in men and 19.9% in women. An estimated 23.4 and 19.2 million men and women had a disease-associated HPV type infection in 2018. Incidences of any and disease-associated HPV infection were 1222 and 672 per 10,000 persons; incidence of disease-associated HPV infection was 708 per 10,000 men and 636 per 10,000 women. An estimated 6.9 and 6.1 million men and women had an incident infection with a disease-associated HPV type in 2018. CONCLUSIONS: We document a high HPV burden of infection in the United States in 2018, with 42 million persons infected with disease-associated HPV and 13 million persons acquiring a new infection. Although most infections clear, some disease-associated HPV type infections progress to disease. The HPV burden highlights the need for continued monitoring of HPV-associated cancers, cervical cancer screening, and HPV vaccination to track and prevent disease.

Modeling the Cost-Effectiveness of Express Multisite Gonorrhea Screening Among Men Who Have Sex With Men in the United States.

BACKGROUND: Men who have sex with men (MSM) experience high rates of gonococcal infection at extragenital (rectal and pharyngeal) anatomic sites, which often are missed without asymptomatic screening and may be important for onward transmission. Implementing an express pathway for asymptomatic MSM seeking routine screening at their clinic may be a cost-effective way to improve extragenital screening by allowing patients to be screened at more anatomic sites through a streamlined, less costly process. METHODS: We modified an agent-based model of anatomic site-specific gonococcal infection in US MSM to assess the cost-effectiveness of an express screening pathway in which all asymptomatic MSM presenting at their clinic were screened at the urogenital, rectal, and pharyngeal sites but forewent a provider consultation and physical examination and self-collected their own samples. We calculated the cumulative health effects expressed as gonococcal infections and cases averted over 5 years, labor and material costs, and incremental cost-effectiveness ratios for express versus traditional scenarios. RESULTS: The express scenario averted more infections and cases in each intervention year. The increased diagnostic costs of triple-site screening were largely offset by the lowered visit costs of the express pathway and, from the end of year 3 onward, this pathway generated small cost savings. However, in a sensitivity analysis of assumed overhead costs, cost savings under the express scenario disappeared in the majority of simulations once overhead costs exceeded 7% of total annual costs. CONCLUSIONS: Express screening may be a cost-effective option for improving multisite anatomic screening among US MSM.

Effectiveness and Cost-Effectiveness of Human Papillomavirus Vaccination Through Age 45 Years in the United States.

Background: In the United States, the routine age for human papillomavirus (HPV) vaccination is 11 to 12 years, with catch-up vaccination through age 26 years for women and 21 years for men. U.S. vaccination policy on use of the 9-valent HPV vaccine in adult women and men is being reviewed. Objective: To evaluate the added population-level effectiveness and cost-effectiveness of extending the current U.S. HPV vaccination program to women aged 27 to 45 years and men aged 22 to 45 years. Design: The analysis used HPV-ADVISE (Agent-based Dynamic model for VaccInation and Screening Evaluation), an individual-based transmission dynamic model of HPV infection and associated diseases, calibrated to age-specific U.S. data. Data Sources: Published data. Target Population: Women aged 27 to 45 years and men aged 22 to 45 years in the United States. Time Horizon: 100 years. Perspective: Health care sector. Intervention: 9-valent HPV vaccination. Outcome Measures: HPV-associated outcomes prevented and cost-effectiveness ratios. Results of Base-Case Analysis: The model predicts that the current U.S. HPV vaccination program will reduce the number of diagnoses of anogenital warts and cervical intraepithelial neoplasia of grade 2 or 3 and cases of cervical cancer and noncervical HPV-associated cancer by 82%, 80%, 59%, and 39%, respectively, over 100 years and is cost saving (vs. no vaccination). In contrast, extending vaccination to women and men aged 45 years is predicted to reduce these outcomes by an additional 0.4, 0.4, 0.2, and 0.2 percentage points, respectively. Vaccinating women and men up to age 30, 40, and 45 years is predicted to cost $830 000, $1 843 000, and $1 471 000, respectively, per quality-adjusted life-year gained (vs. current vaccination). Results of Sensitivity Analysis: Results were most sensitive to assumptions about natural immunity and progression rates after infection, historical vaccination coverage, and vaccine efficacy. Limitation: Uncertainty about the proportion of HPV-associated disease due to infections after age 26 years and about the level of herd effects from the current HPV vaccination program. Conclusion: The current HPV vaccination program is predicted to be cost saving. Extending vaccination to older ages is predicted to produce small additional health benefits and result in substantially higher incremental cost-effectiveness ratios than the current recommendation. Primary Funding Source: Centers for Disease Control and Prevention.

Potential for Point-of-Care Tests to Reduce Chlamydia-associated Burden in the United States: A Mathematical Modeling Analysis.

BACKGROUND: Point-of-care testing (POCT) assays for chlamydia are being developed. Their potential impact on the burden of chlamydial infection in the United States, in light of suboptimal screening coverage, remains unclear. METHODS: Using a transmission model calibrated to data in the United States, we estimated the impact of POCT on chlamydia prevalence, incidence, and chlamydia-attributable pelvic inflammatory disease (PID) incidence, assuming status quo (Analysis 1) and improved (Analysis 2) screening frequencies. We tested the robustness of results to changes in POCT sensitivity, the proportion of patients getting treated immediately, the baseline proportion lost to follow-up (LTFU), and the average treatment delay. RESULTS: In Analysis 1, high POCT sensitivity was needed to reduce the chlamydia-associated burden. With a POCT sensitivity of 90%, reductions from the baseline burden only occurred in scenarios in which over 60% of the screened individuals would get immediate treatment and the baseline LTFU proportion was 20%. With a POCT sensitivity of 99% (baseline LTFU 10%, 2-week treatment delay), if everyone were treated immediately, the prevalence reduction was estimated at 5.7% (95% credible interval [CrI] 3.9-8.2%). If only 30% of tested persons would wait for results, the prevalence reduction was only 1.6% (95% CrI 1.1-2.3). POCT with 99% sensitivity could avert up to 12 700 (95% CrI 5000-22 200) PID cases per year, if 100% were treated immediately (baseline LTFU 20% and 3-week treatment delay). In Analysis 2, when POCT was coupled with increasing screening coverage, reductions in the chlamydia burden could be realized with a POCT sensitivity of 90%. CONCLUSIONS: POCT could improve chlamydia prevention efforts if test performance characteristics are significantly improved over currently available options.

The Potential Population-Level Impact of Different Gonorrhea Screening Strategies in Baltimore and San Francisco: An Exploratory Mathematical Modeling Analysis.

BACKGROUND: Baltimore and San Francisco represent high burden areas for gonorrhea in the United States. We explored different gonorrhea screening strategies and their comparative impact in the 2 cities. METHODS: We used a compartmental transmission model of gonorrhea stratified by sex, sexual orientation, age, and race/ethnicity, calibrated to city-level surveillance data for 2010 to 2017. We analyzed the benefits of 5-year interventions which improved retention in care cascade or increased screening from current levels. We also examined a 1-year outreach screening intervention of high-activity populations. RESULTS: In Baltimore, annual screening of population aged 15 to 24 years was the most efficient of the 5-year interventions with 17.9 additional screening tests (95% credible interval [CrI], 11.8-31.4) needed per infection averted while twice annual screening of the same population averted the most infections (5.4%; 95% CrI, 3.1-8.2%) overall with 25.3 (95% CrI, 19.4-33.4) tests per infection averted. In San Francisco, quarter-annual screening of all men who have sex with men was the most efficient with 16.2 additional (95% CrI, 12.5-44.5) tests needed per infection averted, and it also averted the most infections (10.8%; 95% CrI, 1.2-17.8%). Interventions that reduce loss to follow-up after diagnosis improved outcomes. Depending on the ability of a short-term outreach screening to screen populations at higher acquisition risk, such interventions can offer efficient ways to expand screening coverage. CONCLUSIONS: Data on gonorrhea prevalence distribution and time trends locally would improve the analyses. More focused intervention strategies could increase the impact and efficiency of screening interventions.

The Impact of Screening and Partner Notification on Chlamydia Prevalence and Numbers of Infections Averted in the United States, 2000-2015: Evaluation of Epidemiologic Trends Using a Pair-Formation Transmission Model.

Population-level effects of control strategies on the dynamics of Chlamydia trachomatis transmission are difficult to quantify. In this study, we calibrated a novel sex- and age-stratified pair-formation transmission model of chlamydial infection to epidemiologic data in the United States for 2000-2015. We used sex- and age-specific prevalence estimates from the National Health and Nutrition Examination Surveys, case report data from national chlamydia surveillance, and survey data from the Youth Risk Behavior Survey on the proportion of the sexually active population aged 15-18 years. We were able to reconcile national prevalence estimates and case report data by allowing for changes over time in screening coverage and reporting completeness. In retrospective analysis, chlamydia prevalence was estimated to be almost twice the current levels in the absence of screening and partner notification. Although chlamydia screening and partner notification were both found to reduce chlamydia burden, the relative magnitude of their estimated impacts varied in our sensitivity analyses. The variation in the model predictions highlights the need for further data collection and research to improve our understanding of the natural history of chlamydia and the pathways through which prevention strategies affect transmission dynamics.

Human Papillomavirus Vaccination for Adults: Updated Recommendations of the Advisory Committee on Immunization Practices.

Vaccination against human papillomavirus (HPV) is recommended to prevent new HPV infections and HPV-associated diseases, including some cancers. The Advisory Committee on Immunization Practices (ACIP)* routinely recommends HPV vaccination at age 11 or 12 years; vaccination can be given starting at age 9 years. Catch-up vaccination has been recommended since 2006 for females through age 26 years, and since 2011 for males through age 21 years and certain special populations through age 26 years. This report updates ACIP catch-up HPV vaccination recommendations and guidance published in 2014, 2015, and 2016 (1-3). Routine recommendations for vaccination of adolescents have not changed. In June 2019, ACIP recommended catch-up HPV vaccination for all persons through age 26 years. ACIP did not recommend catch-up vaccination for all adults aged 27 through 45 years, but recognized that some persons who are not adequately vaccinated might be at risk for new HPV infection and might benefit from vaccination in this age range; therefore, ACIP recommended shared clinical decision-making regarding potential HPV vaccination for these persons.

Disparities in Incidence of Human Immunodeficiency Virus Infection Among Black and White Women - United States, 2010-2016.

Incident human immunodeficiency virus (HIV) infections among adolescent females and women declined during 2010-2016, with the largest decrease (21%) occurring among black women (1). However, in 2016, although black women accounted for 13% of the U.S. female population, 60% of new HIV infections among women were in black women, indicating persisting disparities (1). CDC used the population attributable proportion (PAP) disparity measure to describe the proportional decrease in HIV infection among black and white women combined that would be realized if the group with the higher rate (blacks) had the same rate as did the group with the lower rate (whites) (2). Analyses indicated that an estimated 3,900 of 4,200 (93%) incident HIV infections among black women in 2016 would not have occurred if rates were the same for black and white women. The PAP disparity measure decreased from 0.75 in 2010 to 0.70 in 2016, suggesting that if incidence rates for black women were the same as those for white women, the annual number of incident HIV infections among black and white women would have been 75% lower in 2010 and 70% lower in 2016. Continued efforts are needed to identify and address social and structural determinants associated with HIV-related disparities to eliminate these disparities and decrease HIV incidence among black women.

Does including violent crime rates in ecological regression models of sexually transmissible infection rates improve model quality? Insights from spatial regression analyses.

Background Violent crime rates are often correlated with the hard-to-measure social determinants of sexually transmissible infections (STIs). In this study, we examined whether including violent crime rate as an independent variable can improve the quality of ecological regression models of STIs. METHODS: We obtained multiyear (2008-12) cross-sectional county-level data on violent crime and three STIs (chlamydia, gonorrhoea, and primary and secondary (P&S) syphilis) from counties in all the contiguous states in the US (except Illinois and Florida, due to lack of data). We used two measures of STI morbidity (one categorical and one continuous) and applied spatial regression with the spatial error model for each STI, with and without violent crime rate as an independent variable. We computed the associated Akaike's information criterion (AIC) and Bayesian information criterion (BIC) as our measure of the relative goodness of fit of the models. RESULTS: Including the violent crime rate as an independent variable improved the quality of the regression models after controlling for several sociodemographic factors. We found that the lower calculated AICs and BICs indicated more favourable goodness of fit in all the models that included violent crime rates, except for the categorical P&S syphilis model, in which the violent crime variable was not statistically significant. CONCLUSION: Because violent crime rates can account for the hard-to-measure social determinants of STIs, including violent crime rate as an independent variable can improve ecological regression models of STIs.

Relative Impact of Different Strategies for Allocating Federal Funds for Syphilis Prevention.

BACKGROUND: Improvements in resource allocation can increase the benefits of federally funded sexually transmitted disease (STD) prevention activities. The purpose of this study was to illustrate how different strategies for allocating federal funds to subnational districts for syphilis prevention might affect the incidence of syphilis at the national level. METHODS: We modeled syphilis rates by district and year using an equation based on a previous analysis of state-level syphilis elimination funding and syphilis case rates from 1998 to 2005 in the United States. We used the model to illustrate the potential impact of 3 different strategies for allocating supplemental federal funds to subnational districts to support syphilis prevention activities a hypothetical country with 18 subnational districts. The 3 strategies were based on each district's (1) population size, (2) syphilis incidence rate, or (3) number of syphilis cases. The hypothetical country was similar to the United States in overall population and syphilis burden. RESULTS: Without the supplemental federal funds, there would be an estimated 48,600 incident infections annually in the hypothetical country. With the supplemental federal funds, the annual number of infections would be reduced to 27,800 with a population-based allocation of funding to each district, 26,700 with a rate-based allocation, and 24,400 with a case-based allocation of funding. CONCLUSIONS: Allocating federal STD prevention funds to districts based on burden of disease can be an efficient strategy, although this efficiency may be reduced or eliminated when high-burden districts have less ability to provide adequate STD prevention services than lower-burden districts.