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.

Anorectal gonorrhoea and chlamydia among transgender women in Brazil: prevalence and assessment of performance and cost of anorectal infection detection and management approaches.

OBJECTIVES: We aimed to determine the prevalence of anorectal Neisseria gonorrhoeae (NG) and Chlamydia trachomatis (CT) among transgender women in Brazil, and to assess the performance and costs of various approaches for the diagnosis and management of anorectal NG/CT. METHODS: TransOdara was a multicentric, cross-sectional STI prevalence study among 1317 transgender women conducted in five capital cities representing all Brazilian regions. Participants aged >18 years were recruited using respondent-driven sampling (RDS), completed an interviewer-led questionnaire, offered an optional physical examination and given choice between self-collected or provider-collected samples for NG/CT testing. Performance and cost indicators of predetermined management algorithms based on the WHO recommendations for anorectal symptoms were calculated. RESULTS: Screening uptake was high (94.3%) and the estimated prevalence of anorectal NG, CT and NG and/or CT was 9.1%, 8.9% and 15.2%, respectively. Most detected anorectal NG/CT infections were asymptomatic (NG: 87.6%, CT: 88.9%), with a limited number of participants reporting any anorectal symptoms (9.1%). Of those who permitted anal examination, few had clinical signs of infection (13.6%). Sensitivity of the tested algorithms ranged from 1.4% to 5.1% (highest for treatment based on the reported anorectal discharge or ulcer and receptive anal intercourse (RAI) in the past 6 months) and specificity from 98.0% to 99.3% (highest for treatment based on the reported anorectal discharge with clinical confirmation or report of RAI). The estimated cost-per-true case of anorectal NG/CT infection treated varied from lowest providing treatment for anorectal discharge syndrome based on the reported RAI ($2.70-4.28), with algorithms including clinical examinations decreasing cost-effectiveness. CONCLUSIONS: High prevalence of mostly asymptomatic anorectal NG and CT was observed among Brazilian transgender women. Multi-site NG/CT screening should be offered to transgender women. Where diagnostic testing capacity is limited, syndromic management for those presenting with anorectal symptoms is recommended.

Universal ophthalmia neonatorum prophylaxis in Ontario: a cost-effectiveness analysis.

BACKGROUND: Although prophylaxis for ophthalmia neonatorum at birth is required by law in Ontario, declining prevalence of disease and efficacy of prophylaxis have called this practice into question. The objective of this modelling study was to assess the cost-effectiveness of universal prophylaxis for ophthalmia neonatorum to inform decision-makers on the potential impact of a change in this policy. METHODS: We compared the cost-effectiveness of prophylaxis for ophthalmia neonatorum with no prophylaxis through cost-utility analysis with a lifetime time horizon, considering a provincial government payer, for a hypothetical population of newborns in Ontario. We assessed both the mean incremental costs of prophylaxis and its mean incremental effectiveness using a hybrid (part decision tree, part Markov) model. We used a scenario analysis to evaluate alternative time horizons and discount rates. We conducted a threshold analysis to evaluate the impact of variations in the cost of prophylaxis and in the prevalence of sexually transmitted infections (gonorrhea and chlamydia). RESULTS: In our model, prophylaxis for ophthalmia neonatorum did not meet a willingness-to-pay threshold of Can$50 000 per quality-adjusted life-year (QALY). Although prophylaxis was effective in reducing morbidity associated with ophthalmia neonatorum, the number needed to treat to prevent 1 case of ophthalmia neonatorum blindness was 500 000, with an associated cost of more than Can$4 000 000. When compared with no prophylaxis, prophylaxis had an incremental cost of Can$355 798 per long-term QALY gained (incremental cost-effectiveness ratio). INTERPRETATION: We found that prophylaxis for ophthalmia neonatorum, although individually inexpensive, leads to very high costs on a population level. These findings contribute to the discussion on mandatory prophylaxis currently underway in several jurisdictions.

Public health impact and cost-effectiveness of gonorrhoea vaccination: an integrated transmission-dynamic health-economic modelling analysis.

BACKGROUND: Gonorrhoea is a rapidly growing public health threat, with rising incidence and increasing drug resistance. Evidence that the MeNZB and four-component serogroup B meningococcal (4CMenB) vaccines, designed against Neisseria meningitidis, can also offer protection against gonorrhoea has created interest in using 4CMenB for this purpose and for developing gonorrhoea-specific vaccines. However, cost-effectiveness, and how the efficacy and duration of protection affect a gonorrhoea vaccine's value, have not been assessed. METHODS: We developed an integrated transmission-dynamic health-economic model, calibrated using Bayesian methods to surveillance data (from the Genitourinary Medicine Clinic Activity Dataset and the Gonococcal Resistance to Antimicrobials Surveillance Programme) on men who have sex with men (MSM) in England. We considered vaccination of MSM from the perspective of sexual health clinics, with and without vaccination offered to all adolescents in schools (vaccination before entry [VbE]), comparing three realistic approaches to targeting: vaccination on attendance (VoA) for testing; vaccination on diagnosis (VoD) with gonorrhoea; or vaccination according to risk (VaR), offered to patients diagnosed with gonorrhoea plus individuals who test negative but report having more than five sexual partners per year. For the primary analysis, vaccine impact was assessed relative to no vaccination in a conservative baseline scenario wherein time-varying behavioural parameters (sexual risk behaviour and screening rates) stabilise. To calculate the value of vaccination per dose administered, the value of vaccination was calculated by summing the averted costs of testing and treatment, and the monetary value of quality-adjusted life-year (QALY) gains with a QALY valued at £20 000. Costs were in 2018-19 GB£, and both costs and QALYs were discounted at 3·5% per year. We analysed the effects of varying vaccine uptake (0·5, 1, or 2 times HPV vaccine uptake by MSM in sexual health clinics in England), vaccine efficacy (1-100%) and duration of protection (1-20 years), and the time-horizon considered (10 years and 20 years). In addition, we calculated incremental cost-effectiveness ratios for the use of 4CMenB using assumed vaccine prices. FINDINGS: VbE has little impact on gonorrhoea diagnoses, with only 1·7% of MSM vaccinated per year. VoA has the largest impact but requires more vaccine doses than any other strategy, whereas VoD has a moderate impact but requires many fewer doses than VoA. VaR has almost the same impact as VoA but with fewer doses administered than VoA. VaR is the most cost-effective strategy for vaccines of moderate efficacy or duration of protection (or both), although VoD is more cost-effective for very protective and long-lasting vaccines. Even under conservative assumptions (efficacy equivalent to that of MeNZB and protection lasting for 18 months after two-dose primary vaccination and 36 months after single-dose booster vaccination), 4CMenB administered under VaR would likely be cost-saving at its current National Health Service price, averting an estimated mean 110 200 cases (95% credible interval 36 500-223 600), gaining a mean 100·3 QALYs (31·0-215·8), and saving a mean £7·9 million (0·0-20·5) over 10 years. A hypothetical gonorrhoea vaccine's value is increased more by improving its efficacy than its duration of protection-eg, 30% protection lasting 2 years has a median value of £48 (22-85) per dose over 10 years; doubling efficacy increases the value to £102 (53-144) whereas doubling the duration of protection increases it to £72 (34-120). INTERPRETATION: We recommend that vaccination of MSM against gonorrhoea according to risk in sexual health clinics in England with the 4CMenB vaccine be considered. Development of gonorrhoea-specific vaccines should prioritise maximising efficacy over duration of protection. FUNDING: Medical Research Council (UK), National Institute for Health Research (UK).

Direct and Indirect Cost Savings From Sexually Transmitted Infection Testing, Treatment, and Counseling Among Foster Youth.

BACKGROUND: Sexually transmitted infection (STI) prevention programs can decrease the economic burden of STIs. Foster youth have higher rates of STIs compared with their peers; however, information on direct costs and indirect costs averted by STI testing, treatment, and counseling among foster youth is lacking. METHODS: This study used data from a comprehensive medical center for foster youth over a 3-year study period from July 2017 to June 2020. Direct and indirect costs averted by testing and treatment of chlamydia, gonorrhea, and syphilis, as well as HIV testing and counseling, were calculated based on formulas developed by the Centers for Disease Control and Prevention and adjusted for inflation. RESULTS: Among the 316 youth who received medical services during this time, 206 were sexually active and tested for STIs and/or HIV. Among 121 positive STI test results, 64.5% (n = 78) were positive for chlamydia, 30.6% (n = 37) were positive for gonorrhea, and 5.0% (n = 6) were positive for syphilis. Treatment was provided to all. Overall, $60,049.68 in direct medical costs and $73,956.36 in indirect costs were averted. CONCLUSIONS: Given the rates of STIs among this population and the economic benefit of STI treatment, it is imperative to continue to provide intensive and comprehensive, individualized sexual health care for foster youth. Traditional care management may miss the opportunity to prevent, identify, and treat STIs that comprehensive wraparound care can achieve. This study suggests that comprehensive wraparound care is a cost-effective way to identify, treat, and prevent STIs among foster youth.

Assessment of Serum Bactericidal and Opsonophagocytic Activity of Antibodies to Gonococcal Vaccine Targets.

There is no vaccine available to prevent Neisseria gonorrhoeae infection, however there is currently a high level of interest in developing gonococcal vaccines due to the increasing number of cases and continuing emergence of antimicrobial resistance worldwide. A key aspect of vaccine development is the investigation of the functional immune response raised to the vaccine targets under investigation. Here, we describe two assays used to assess the functional immune response raised against gonococcal vaccine targets: the serum bactericidal assay (SBA) and the opsonophagocytic assay (OPA).

The Estimated Impact of Implementing a Funding Allocation Formula on the Number of Gonorrhea Cases in the United States, 2014 to 2018.

BACKGROUND: The Centers for Disease Control and Prevention (CDC) allocates funds annually to state and local programs in the United States to monitor and prevent sexually transmitted diseases (STDs). In 2014, a funding formula was implemented to allocate prevention funds to jurisdictions according to their STD burden and population size. We estimated the effect of implementing the funding formula in terms of gonorrhea cases averted from 2014 to 2018, a period during which inflation-adjusted CDC STD prevention funding declined. METHODS: Our model assumed that STD prevention funds have a measurable effect on subsequent reported gonorrhea case rates, and the magnitude of this effect was as estimated in an empirical analysis of decades of state-level gonorrhea rates. In applying this equation-based model, we assumed all factors affecting jurisdictions' gonorrhea rates were constant over time except for their STD prevention funding allocations. We used data on CDC STD prevention funding allocated to each jurisdiction over time. We estimated gonorrhea rates under the "funding formula" scenario compared with a hypothetical "status quo" funding scenario, which reflected traditional methods to allocate prevention funds. RESULTS: In the model, gonorrhea cases increased from 2014 to 2018 by approximately 6% because of a decline in prevention funding, regardless of how funds were allocated. However, the estimated increase in gonorrhea cases was 5222 (range, 1181-9195) cases less in the funding formula scenario than in the status quo scenario. CONCLUSIONS: By shifting resources toward jurisdictions with greater disease burden, the funding formula averted a substantial number of gonorrhea cases at no additional cost.

Twelve-Year Longitudinal Trends in Trachoma Prevalence among Children Aged 1-9 Years in Amhara, Ethiopia, 2007-2019.

Trachoma control in the Amhara region of Ethiopia, where all districts were once endemic, began in 2001 and attained full scale-up of the Surgery, Antibiotics, Facial cleanliness, and Environmental improvement (SAFE) strategy by 2010. Since scaling up, the program has distributed approximately 14 million doses of antibiotic per year, implemented village- and school-based health education, and promoted latrine construction. This report aims to provide an update on the prevalence of trachoma among children aged 1-9 years as of the most recent impact or surveillance survey in all 160 districts of Amhara. As of 2019, 45 (28%) districts had a trachomatous inflammation-follicular (TF) prevalence below the 5% elimination threshold. There was a statistically significant relationship between TF prevalence observed at the first impact survey (2010-2015) and eventual achievement of TF < 5% (2015-2019). Of the 26 districts with a first impact survey < 10% TF, 20 (76.9%) had < 5% TF at the most recent survey. Of the 75 districts with a first survey between 10% and 29.9% TF, 21 (28.0%) had < 5% TF at the most recent survey. Finally, among 59 districts ≥ 30% TF at the first survey, four (6.8%) had < 5% TF by 2019. As of 2019, 30 (18.8%) districts remained with TF ≥ 30%. Amhara has seen considerable reductions of trachoma since the start of the program. A strong commitment to the SAFE strategy coupled with data-driven enhancements to that strategy is necessary to facilitate timely elimination of trachoma as a public health problem regionally in Amhara and nationwide in Ethiopia.

Cost-effectiveness of two screening strategies for Chlamydia trachomatis and Neisseria gonorrhoeae as part of the PrEP programme in the Netherlands: a modelling study.

OBJECTIVES: Pre-exposure prophylaxis (PrEP) users are routinely tested four times a year (3 monthly) for asymptomatic Chlamydia trachomatis (CT) and Neisseria gonorrhoeae (NG) infections on three anatomical locations. Given the high costs of this testing to the PrEP programme, we assessed the impact of 3 monthly screening(current practice), compared with 6 monthly on the disease burden. We quantified the difference in impact of these two testing frequencies on the prevalence of CT and NG among all men who have sex with men (MSM) who are at risk of an STI, and explored the cost-effectiveness of 3-monthly screening compared with a baseline scenario of 6-monthly screening. METHODS: A dynamic infection model was developed to simulate the transmission of CT and NG among sexually active MSM (6500 MSM on PrEP and 29 531 MSM not on PrEP), and the impact of two different test frequencies over a 10-year period. The difference in number of averted infections was used to calculate incremental costs and quality-adjusted life-years (QALY) as well as an incremental cost-effectiveness ratio (ICER) from a societal perspective. RESULTS: Compared with 6-monthly screening, 3-monthly screening of PrEP users for CT and NG cost an additional €46.8 million over a period of 10 years. Both screening frequencies would significantly reduce the prevalence of CT and NG, but 3-monthly screening would avert and extra ~18 250 CT and NG infections compared with 6-monthly screening, resulting in a gain of ~81 QALYs. The corresponding ICER was ~€430 000 per QALY gained, which exceeded the cost-effectiveness threshold of €20 000 per QALY. CONCLUSIONS: Three-monthly screening for CT and NG among MSM on PrEP is not cost-effective compared with 6-monthly screening. The ICER becomes more favourable when a smaller fraction of all MSM at risk for an STI are screened. Reducing the screening frequency could be considered when the PrEP programme is established and the prevalence of CT and NG decline.

Point-of-Care Testing for Sexually Transmitted Infections: A Review of Recent Developments.

CONTEXT.­: Sexually transmitted infections (STIs) are among the most common communicable diseases globally and are associated with significant morbidity and mortality worldwide. Point-of-care tests have the potential to revolutionize the prevention and control of STIs by enabling rapid diagnosis and early treatment of infections, thus interrupting transmission and preventing the sequelae of untreated infections. Currently, there are several point-of-care (POC) tests available for the diagnosis of Treponema pallidum, Chlamydia trachomatis, Neisseria gonorrhoeae, and Trichomonas vaginalis infections, although these tests differ with regard to their performance, turnaround time, and cost. OBJECTIVE.­: To provide an updated review of the POC tests available and under development for the diagnosis of T pallidum, C trachomatis, N gonorrhoeae, and T vaginalis infections, to discuss the context for which these tests might be used, and to highlight future directions for test development. DATA SOURCES.­: We reviewed the literature pertaining to the recent development and performance evaluations of POC tests for the diagnosis of syphilis, chlamydia, gonorrhea, and trichomonas. CONCLUSIONS.­: Recently, there has been rapid development of new POC tests for STIs. Although there are inexpensive, rapid, and accurate POC tests available for syphilis, there are few such tests available for the diagnosis of chlamydia, gonorrhea, or trichomonas, and currently none with the ability to detect antimicrobial resistance in N gonorrhoeae. Research evaluating implementation strategies for the currently available tests and the development of additional POC tests that are rapid, accurate, and affordable are urgently needed to address the rising number of STIs worldwide.

Gonococcal vaccines: Public health value and preferred product characteristics; report of a WHO global stakeholder consultation, January 2019.

Renewed interest in developing vaccines against Neisseria gonorrhoeae has been sparked by the increasing threat of gonococcal antimicrobial resistance (AMR) and growing optimism that gonococcal vaccines are biologically feasible. Evidence suggests serogroup B Neisseria meningitidis vaccines might provide some cross-protection against N. gonorrhoeae, and new gonococcal vaccine candidates based on several approaches are currently in preclinical development. To further stimulate investment and accelerate development of gonococcal vaccines, greater understanding is needed regarding the overall value that gonococcal vaccines might have in addressing public health and societal goals in low-, middle-, and high-income country contexts and how future gonococcal vaccines might be accepted and used, if available. In January 2019, the World Health Organization (WHO) convened a multidisciplinary international group of experts to lay the groundwork for understanding the potential health, economic, and societal value of gonococcal vaccines and their likely acceptance and use, and for developing gonococcal vaccine preferred product characteristics (PPCs). WHO PPCs describe preferences for vaccine attributes that would help optimize vaccine value and use in meeting the global public health need. This paper describes the main discussion points and conclusions from the January 2019 meeting of experts. Participants emphasized the need for vaccines to control N. gonorrhoeae infections with the ultimate goals of preventing adverse sexual and reproductive health outcomes (e.g., infertility) and reducing the impact of gonococcal AMR. Meeting participants also discussed important PPC considerations (e.g., vaccine indications, target populations, and potential immunization strategies) and highlighted crucial research and data needs for guiding the value assessment and PPCs for gonococcal vaccines and advancing gonococcal vaccine development.

Provider attitudes to the empiric treatment of asymptomatic contacts of gonorrhoea.

Background In the current era of antimicrobial stewardship, the availability of highly sensitive assays and faster turnaround times, the practice of empiric treatment of asymptomatic contacts of gonorrhoea needs review. The views of clinicians in a range of settings across Australia and clinic costs associated with a change of practice was examined. METHODS: An online anonymous survey for nurses and doctors working in public sexual health clinics and general practices in urban, regional and rural Australia was developed. Information on the relative importance of a range of factors influencing delivery of empiric treatment was collected. Participants were asked whether current guidelines should change. RESULTS: Surveys were distributed to 468 healthcare providers and 188 (40.2%) fully completed the survey. Most of the participants worked in public practice (84.9%) and 86 (43.2%) were doctors. Factors influencing provision of empiric treatment were: if the patient was unable to return (95.9%) or may not return (95.3%); risk of transmission to others (93.3%); likelihood of infection (88.6%); and patient request (82.9%). Respondents were evenly split as to whether current guidelines should change, with providers in private practice being less likely to support guideline change (P = 0.03). The model of empiric treatment of all asymptomatic sexual contacts was 34% more expensive than a model of testing and treatment of those with a positive result. CONCLUSION: Currently, the majority of clinicians provide empiric treatment for asymptomatic contacts in Australia. There was significant support for a change in guidelines with specific scenarios requiring individualised responses.

Assessment of the Potential of Vaccination to Combat Antibiotic Resistance in Gonorrhea: A Modeling Analysis to Determine Preferred Product Characteristics.

BACKGROUND: Gonorrhea incidence is increasing rapidly in many countries, while antibiotic resistance is making treatment more difficult. Combined with evidence that two meningococcal vaccines are likely partially protective against gonorrhea, this has renewed interest in a gonococcal vaccine, and several candidates are in development. Key questions are how protective and long-lasting a vaccine needs to be, and how to target it. We assessed vaccination's potential impact and the feasibility of achieving the World Health Organization's (WHO) target of reducing gonorrhea incidence by 90% during 2018-2030, by comparing realistic vaccination strategies under a range of scenarios of vaccine efficacy and duration of protection, and emergence of extensively-resistant gonorrhea. METHODS: We developed a stochastic transmission-dynamic model, incorporating asymptomatic and symptomatic infection and heterogeneous sexual behavior in men who have sex with men (MSM). We used data from England, which has a comprehensive, consistent nationwide surveillance system. Using particle Markov chain Monte Carlo methods, we fitted to gonorrhea incidence in 2008-2017, then used Bayesian forecasting to examine an extensive range of scenarios. RESULTS: Even in the worst-case scenario of untreatable infection emerging, the WHO target is achievable if all MSM attending sexual health clinics receive a vaccine offering ≥ 52% protection for ≥ 6 years. A vaccine conferring 31% protection (as estimated for MeNZB) for 2-4 years could reduce incidence in 2030 by 45% in the worst-case scenario, and by 75% if > 70% of resistant gonorrhea remains treatable. CONCLUSIONS: Even a partially-protective vaccine, delivered through a realistic targeting strategy, could substantially reduce gonorrhea incidence, despite antibiotic resistance.

Preexposure prophylaxis for men who have sex with men in the Netherlands: impact on HIV and Neisseria gonorrhoeae transmission and cost-effectiveness.

OBJECTIVES: To assess the impact of a preexposure prophylaxis (PrEP) programme for high-risk men who have sex with men (MSM), which includes gonorrhoea testing and treatment, on the transmission of HIV and Neisseria among MSM in the Netherlands and the cost-effectiveness of such programme with and without risk compensation (in the form of reduced condom use). METHODS: We developed a stochastic agent-based transmission model of HIV and gonorrhoea. We simulated a capped (max 2.5% of MSM) and uncapped (5.5% of MSM in 2018 declining to 3% in 2027) daily PrEP programme for high-risk MSM, with 3-monthly HIV and gonorrhoea testing, with and without risk compensation. Epidemiological outcomes were calculated from the transmission model and used in an economic model to calculate costs, quality-adjusted life-years (QALY), and incremental cost-effectiveness ratios (ICER), over 2018-2027, taking a healthcare payer perspective. RESULTS: Without risk compensation, PrEP can lead to a reduction of 61 or 49% in the total number of new HIV infections in 2018-2027, if the programme is uncapped or capped to 2.5% of MSM, respectively. With risk compensation, this reduction can be 63 or 46% in the uncapped and capped programmes, respectively. In all scenarios, gonorrhoea prevalence decreased after introducing PrEP. Without risk compensation, 92% of simulations were cost-effective (of which 52% cost-saving). With risk compensation, 73% of simulations were cost-effective (of which 23% was cost-saving). CONCLUSION: A nationwide PrEP programme for high-risk MSM can result in substantial reductions in HIV and gonorrhoea transmission and be cost-effective, even with risk compensation.

Modeling Public Health Campaigns for Sexually Transmitted Infections via Optimal and Feedback Control.

Control of sexually transmitted infections (STIs) poses important challenges to public health authorities. Obstacles for STIs' control include low priority in public health programs and disease transmission mechanisms. This work uses a compartmental pair model to explore different public health strategies on the evolution of STIs. Optimal control and feedback control are used to model realistic strategies for reducing the prevalence of these infections. Feedback control is proposed to model the reaction of public health authorities relative to an alert level. Optimal control is used to model the optimization of available resources for implementing strategies. Numerical simulations are performed using trichomoniasis, gonorrhea, chlamydia and human papillomavirus (HPV) as study cases. HPV is non-curable, and it is analyzed only under transmission control such as condom promotion campaigns. Trichomoniasis, gonorrhea and chlamydia are curable STIs that are modeled here additionally under treatment control. Increased cost-effectiveness ratio is employed as a criterion to measure control strategies performance. The features and drawbacks of control strategies under the pair formation process are discussed.

Improving Women's Health and Combatting Sexually Transmitted Infections Through Expedited Partner Therapy.

Sexually transmitted infections (STI), including Chlamydia trachomatis and Neisseria gonorrhoeae, have reached record high rates in the United States. Sexually transmitted infections disproportionately affect reproductive-aged females aged 15-44 years, who account for 65% and 42% of the total reported C trachomatis and N gonorrhoeae cases, respectively. Undiagnosed STIs can result in serious health complications that put women at an increased risk for pelvic inflammatory disease, ectopic pregnancy, and tubal factor infertility. Many of these women are seen by physicians (eg, obstetrician-gynecologists, family medicine doctors, pediatricians) or other clinicians (eg, nurse practitioners, midwives, physician assistants) who care for women. These clinicians have the opportunity to help curb the continued increase in STI incidence rates with the implementation and use of expedited partner therapy. Expedited partner therapy is a proven effective health care practice that allows clinicians to give patients medications or prescriptions to distribute to their partners. Despite expedited partner therapy's proven effectiveness, there are barriers to its implementation that must be understood to enhance STI treatment and prevention efforts. In this commentary, we discuss these barriers, and appeal to women's health clinicians to implement or increase use of expedited partner therapy for the treatment of women with STIs and their sexual partners.

Impacts of Federal Prevention Funding on Reported Gonorrhea and Chlamydia Rates.

INTRODUCTION: The Centers for Disease Control and Prevention allocates funds annually to jurisdictions nationwide for sexually transmitted infection prevention activities. The objective of this study was to assess the effectiveness of federal sexually transmitted infection prevention funding for reducing rates of reported sexually transmitted infections. METHODS: In 2017-2018, finite distributed lag regression models were estimated to assess the impact of sexually transmitted infection prevention funding (in 2016 dollars per capita) on reported chlamydia rates from 2000 to 2016 and reported gonorrhea rates from 1981 to 2016. Including lagged funding measures allowed for assessing the impact of funding over time. Controls for state-level socioeconomic factors, such as poverty rates, were included. RESULTS: Results from the main model indicate that a 1% increase in annual funding would cumulatively decrease chlamydia and gonorrhea rates by 0.17% (p<0.10) and 0.33% (p<0.05), respectively. Results were similar when stratified by sex, with significant decreases in rates of reported chlamydia and gonorrhea in males of 0.33% and 0.34% (both p<0.05) respectively, and in rates of reported gonorrhea in females of 0.32% (p<0.05). The results were generally consistent across alternative model specifications and other robustness tests. CONCLUSIONS: The significant inverse associations between federal sexually transmitted infection prevention funding and rates of reported chlamydia and gonorrhea suggest that federally funded sexually transmitted infection prevention activities have a discernable effect on reducing the burden of sexually transmitted infections. The reported sexually transmitted infection rate in a given year depends more on prevention funding in previous years than on prevention funding in the current year, demonstrating the importance of accounting for lagged funding effects.

Biological feasibility and importance of a gonorrhea vaccine for global public health.

There is a growing public health interest in controlling sexually transmitted infections (STIs) through vaccination due to increasing recognition of the global disease burden of STIs and the role of STIs in women's reproductive health, adverse pregnancy outcomes, and the health and well-being of neonates. Neisseria gonorrhoeae has historically challenged vaccine development through the expression of phase and antigenically variable surface molecules and its capacity to cause repeated infections without inducing protective immunity. An estimated 78 million new N. gonorrhoeae infections occur annually and the greatest disease burden is carried by low- and middle-income countries (LMIC). Current control measures are clearly inadequate and threatened by the rapid emergence of antibiotic resistance. The gonococcus now holds the status of "super-bug" as there is currently no single reliable monotherapy for empirical treatment of gonorrhea. The problem of antibiotic resistance has elevated treatment costs and necessitated the establishment of large surveillance programs to track the spread of resistant strains. Here we review the need for a gonorrhea vaccine with respect to global disease burden and related socioeconomic and treatment costs, with an emphasis on the impact of gonorrhea on women and newborns. We also highlight the challenge of estimating the impact of a gonorrhea vaccine due to the need for more data on the burden of gonococcal pelvic inflammatory disease and related sequelae and of gonorrhea-associated adverse pregnancy outcomes and the problem of empirical diagnosis and treatment of STIs in LMIC. There is also a lack of clinical and basic science research in the area of gonococcal/chlamydia coinfection, which occurs in a high percentage of individuals with gonorrhea and should be considered when testing the efficacy of gonorrhea vaccines. Finally, we review recent research that suggests a gonorrhea vaccine is feasible and discuss challenges and research gaps in gonorrhea vaccine development.

Toward economic evaluation of the value of vaccines and other health technologies in addressing AMR.

We discuss the need to make economic evaluations of vaccines antimicrobial resistance (AMR)-sensitive and ways to do so. Such AMR-sensitive evaluations can play a role in value-for-money comparisons of different vaccines within a national immunization program, or in comparisons of vaccine-centric and non-vaccine-centric technologies within an anti-AMR program. In general terms, incremental cost-effectiveness ratios and rates of return and their associated decision rules are unaltered by consideration of AMR-related value. The decision metrics need to have their various health, cost, and socioeconomic terms disaggregated into resistance-related subcategories, which in turn have to be measured carefully before they are reaggregated. The fundamental scientific challenges lie primarily in quantifying the causal impact of health technologies on resistance-related health outcomes, and secondarily in ascertaining the economic value of those outcomes. We emphasize the importance of evaluating vaccines in the context of other potentially complementary and substitutable nonvaccine technologies. Complementarity implies that optimal spending on each set of interventions is positive, and substitutability implies that the ratio of spending will depend on relative value for money. We exemplify this general point through a qualitative discussion of the complementarities and (especially the) substitutability between pneumococcal conjugate vaccines and antimicrobial stewardship and between research and development (R&D) of a gonorrhea vaccine versus R&D of a gonorrhea antibiotic. We propose a roadmap for future work, which includes quantifying the causal effects of vaccination and other health technologies on short-term and long-term resistance-related outcomes, measuring the health-sector costs and broader socioeconomic consequences of resistance-related mortality and morbidity, and evaluating vaccines in the context of nonvaccine complements and substitutes.