Geospatial Disparities in Youth Sexually Transmitted Infections During COVID-19.

INTRODUCTION: Early in the COVID-19 pandemic, routine sexually transmitted infection (STI) screenings decreased, and test positivity rates increased due to limited screening appointments, national-level STI testing supply shortages, and social distancing mandates. It is unclear if adolescent preventive STI screening has returned to pre-pandemic levels and if pre-existing disparities worsened in late-pandemic. METHODS: This cross-sectional study examined 22,974 primary care visits by 13-19-year-olds in the Philadelphia metropolitan area undergoing screening for gonorrhea and chlamydia in a 31-clinic pediatric primary care network during 2018-2022. Using interrupted-time-series analysis and logistic regression, pandemic-related changes in the asymptomatic STI screening rate and test positivity were tracked across patient demographics. Neighborhood moderation was investigated by census-tract-level Child Opportunity Index in 2023. RESULTS: The asymptomatic STI screening rate dropped by 27.8 percentage points (pp) and 13.5pp when the pandemic and national STI test supply shortage began, respectively, but returned to pre-pandemic levels after supply availability was restored in early 2021. Non-Hispanic-Black adolescents had a significant pandemic drop in STI screening rate, and it did not return to prep-andemic levels (-3.6 pp in the late-pandemic period, p<0.01). This decrease was more pronounced in socioeconomically and educationally disadvantaged neighborhoods (7.5 pp and 9.9 pp lower, respectively) than in advantaged neighborhoods (both p<0.001), controlling for sex, age, insurance type and clinic characteristics. CONCLUSIONS: Neighborhood socioeconomic and educational disadvantage amplified racial-ethnic disparities in STI screening during the pandemic. Future interventions should focus on improving primary care utilization of non-Hispanic-Black adolescents to increase routine STI screening and preventive care utilization.

Measuring Variation in Infant Mortality and Deaths of Despair by U.S. Congressional Districts in Pennsylvania: A Methodological Case Study.

Many ecological studies examine health outcomes and disparities using administrative boundaries such as census tracts, counties, or states. These boundaries help us to understand the patterning of health by place along with impacts of policies implemented at these levels. However, additional geo-political units, or units with both geographic and political meaning, such as congressional districts, present further opportunities to connect research with public policy. We provide a step-by-step guide in how to conduct disparities-focused analysis at the congressional district level, and as an applied case study we use geocoded vital statistics data from 2010-2015 to examine levels and disparities of infant mortality (IM) and deaths of despair (DoD) in the 19 U.S. congressional districts of Pennsylvania for the 111th-112th (2009-2012) Congresses, and 18 districts for the 113th-114th (2013-2016) Congresses. We also provide recommendations for extending congressional district level analysis to other outcomes, states, and geopolitical boundaries such as state legislative districts. Increased surveillance of health outcomes at the congressional district level can help prompt policy action, advocacy, and hopefully, reduce rates and disparities in health.

A catchment and location-allocation analysis of mammography access in Delaware, US: implications for disparities in geographic access to breast cancer screening.

BACKGROUND: Despite a 40% reduction in breast cancer mortality over the last 30 years, not all groups have benefited equally from these gains. A consistent link between later stage of diagnosis and disparities in breast cancer mortality has been observed by race, socioeconomic status, and rurality. Therefore, ensuring equitable geographic access to screening mammography represents an important priority for reducing breast cancer disparities. Access to breast cancer screening was evaluated in Delaware, a state that experiences an elevated burden from breast cancer but is otherwise representative of the US in terms of race and urban-rural characteristics. We first conducted a catchment analysis of mammography facilities. Finding evidence of disparities by race and rurality, we next conducted a location-allocation analysis to identify candidate locations for the establishment of new mammography facilities to optimize equitable access. METHODS: A catchment analysis using the ArcGIS Pro Service Area analytic tool characterized the geographic distribution of mammography sites and Breast Imaging Centers of Excellence (BICOEs). Poisson regression analyses identified census tract-level correlates of access. Next, the ArcGIS Pro Location-Allocation analytic tool identified candidate locations for the placement of additional mammography sites in Delaware according to several sets of breast cancer screening guidelines. RESULTS: The catchment analysis showed that for each standard deviation increase in the number of Black women in a census tract, there were 68% (95% CI 38-85%) fewer mammography units and 89% (95% CI 60-98%) fewer BICOEs. The more rural counties in the state accounted for 41% of the population but only 22% of the BICOEs. The results of the location-allocation analysis depended on which set of screening guidelines were adopted, which included increasing mammography sites in communities with a greater proportion of younger Black women and in rural areas. CONCLUSIONS: The results of this study illustrate how catchment and location-allocation analytic tools can be leveraged to guide the equitable selection of new mammography facility locations as part of a larger strategy to close breast cancer disparities.

Alignment of Ending the HIV Epidemic Priority Jurisdictions With Availability of HIV Service Organizations: An Ecological Study.

We sought to describe and quantify the association between HIV service organization availability, HIV burden, and HIV awareness and prevention in the 57 priority jurisdictions selected as part of the U.S. Ending the HIV Epidemic initiative. On average, jurisdictions with more per capita organizations had more people living with HIV, more individuals aware of their positive status, and more individuals prescribed PrEP (b = 0.3; 95% CI [0.2, 0.5] for each additional case per 1,000 people in the first metric, and b = 0.3; 95% CI [0.2, 0.4] and b = 0.1; 95% CI [< 0.1, 0.1], respectively, for each percentage point change in the second two metrics), accounting for jurisdiction size. Several jurisdictions were outliers in the modeled associations and may reflect comparatively better, or worse, performance than similar jurisdictions. This information can assist in evaluating resource allocation and determining whether availability translates to accessibility.

Modeling the impact of xenointoxication in dogs to halt Trypanosoma cruzi transmission.

BACKGROUND: Chagas disease, a vector-borne parasitic disease caused by Trypanosoma cruzi, affects millions in the Americas. Dogs are important reservoirs of the parasite. Under laboratory conditions, canine treatment with the systemic insecticide fluralaner demonstrated efficacy in killing Triatoma infestans and T. brasiliensis, T. cruzi vectors, when they feed on dogs. This form of pest control is called xenointoxication. However, T. cruzi can also be transmitted orally when mammals ingest infected bugs, so there is potential for dogs to become infected upon consuming infected bugs killed by the treatment. Xenointoxication thereby has two contrasting effects on dogs: decreasing the number of insects feeding on the dogs but increasing opportunities for exposure to T. cruzi via oral transmission to dogs ingesting infected insects. OBJECTIVE: Examine the potential for increased infection rates of T. cruzi in dogs following xenointoxication. DESIGN/METHODS: We built a deterministic mathematical model, based on the Ross-MacDonald malaria model, to investigate the net effect of fluralaner treatment on the prevalence of T. cruzi infection in dogs in different epidemiologic scenarios. We drew upon published data on the change in percentage of bugs killed that fed on treated dogs over days post treatment. Parameters were adjusted to mimic three scenarios of T. cruzi transmission: high and low disease prevalence and domestic vectors, and low disease prevalence and sylvatic vectors. RESULTS: In regions with high endemic disease prevalence in dogs and domestic vectors, prevalence of infected dogs initially increases but subsequently declines before eventually rising back to the initial equilibrium following one fluralaner treatment. In regions of low prevalence and domestic or sylvatic vectors, however, treatment seems to be detrimental. In these regions our models suggest a potential for a rise in dog prevalence, due to oral transmission from dead infected bugs. CONCLUSION: Xenointoxication could be a beneficial and novel One Health intervention in regions with high prevalence of T. cruzi and domestic vectors. In regions with low prevalence and domestic or sylvatic vectors, there is potential harm. Field trials should be carefully designed to closely follow treated dogs and include early stopping rules if incidence among treated dogs exceeds that of controls.

Geolocation to Identify Online Study-Eligible Gay, Bisexual, and Men who have Sex with Men in Philadelphia, Pennsylvania.

BACKGROUND: Data collection and cleaning procedures to exclude bot-generated responses are used to maintain the data integrity of samples from online surveys. However, these procedures may be time-consuming and difficult to implement. Thus, we aim to evaluate the validity of a single-step geolocation algorithm for recruiting eligible gay, bisexual, and men who have sex with men in Philadelphia for an online study. METHODS: We used a 4-step approach, based on common practices for evaluating bot-generated and fraudulent responses, to assess the validity of participants' Qualtrics survey data as our referent standard. We then compared it to Qualtrics' single-step geolocation algorithm that used the MaxMind commercial database to map participants' Internet protocol address to their approximate location. We calculated the sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the single-step geolocation approach relative to the 4-step approach. RESULTS: There were 826 respondents who completed the survey and 440 (53%) were eligible for enrollment based on the 4-step approach. The single-step geolocation approach yielded a sensitivity of 91% (95% CI = 88%, 93%), specificity of 79% (95% CI = 74%, 83%), PPV of 83% (95% CI = 80%, 86%), and NPV of 88% (95% CI = 85%, 91%). CONCLUSIONS: Geolocation alone provided a moderately high level of agreement with the 4-step approach for identifying geographically eligible participants in the online sample, but both approaches may be subject to additional misclassification. Researchers may want to consider multiple procedures to ensure data integrity in online samples.

A Catchment and Location-Allocation Analysis of Mammography Access in Delaware, US: Implications for disparities in geographic access to breast cancer screening.

Background: Despite a 40% reduction in breast cancer mortality over the last 30 years, not all groups have benefited equally from these gains. A consistent link between later stage of diagnosis and disparities in breast cancer mortality has been observed by race, socioeconomic status, and rurality. Therefore, ensuring equitable geographic access to screening mammography represents an important priority for reducing breast cancer disparities. This study conducted a catchment and location-allocation analysis of mammography access in Delaware, a state that is representative of the US in terms of race and urban-rural characteristics and experiences an elevated burden from breast cancer. Methods: A catchment analysis using the ArcGIS Pro Service Area analytic tool characterized the geographic distribution of mammography sites and Breast Imaging Centers of Excellence (BICOEs). Poisson regression analyses identified census tract-level correlates of access. Next, the ArcGIS Pro Location-Allocation analytic tool identified candidate locations for the placement of additional mammography sites in Delaware according to several sets of breast cancer screening guidelines. Results: The catchment analysis showed that for each standard deviation increase in the number of Black women in a census tract, there were 64% (95% CI, 0.18-0.66) fewer mammography units and 85% (95% CI, 0.04-0.48) fewer BICOEs. The more rural counties in the state accounted for 41 % of the population but only 22% of the BICOEs. The results of the location-allocation analysis depended on which set of screening guidelines were adopted, which included increasing mammography sites in communities with a greater proportion of younger Black women and in rural areas. Conclusions: The results of this study illustrate how catchment and location-allocation analytic tools can be leveraged to guide the equitable selection of new mammography facility locations as part of a larger strategy to close breast cancer disparities.

Modeling the impact of xenointoxication in dogs to halt Trypanosoma cruzi transmission.

Background: Chagas disease, a vector-borne parasitic disease caused by Trypanosoma cruzi , affects millions in the Americas. Dogs are important reservoirs of the parasite. Under laboratory conditions, canine treatment with the systemic insecticide fluralaner demonstrated efficacy in killing Triatoma infestans and T. brasiliensis, T. cruzi vectors, when they feed on dogs. This form of pest control is called xenointoxication. However, T. cruzi can also be transmitted orally when mammals ingest infected bugs, so there is potential for dogs to become infected upon consuming infected bugs killed by the treatment. Xenointoxication thereby has two contrasting effects on dogs: decreasing the number of insects feeding on the dogs but increasing opportunities for exposure to T. cruzi via oral transmission to dogs ingesting infected insects. Objective: Examine the potential for increased infection rates of T. cruzi in dogs following xenointoxication. Design/Methods: We built a deterministic mathematical model, based on the Ross-MacDonald malaria model, to investigate the net effect of fluralaner treatment on the prevalence of T. cruzi infection in dogs in different epidemiologic scenarios. We drew upon published data on the change in percentage of bugs killed that fed on treated dogs over days post treatment. Parameters were adjusted to mimic three scenarios of T. cruzi transmission: high and low disease prevalence and domestic vectors, and low disease prevalence and sylvatic vectors. Results: In regions with high endemic disease prevalence in dogs and domestic vectors, prevalence of infected dogs initially increases but subsequently declines before eventually rising back to the initial equilibrium following one fluralaner treatment. In regions of low prevalence and domestic or sylvatic vectors, however, treatment seems to be detrimental. In these regions our models suggest a potential for a rise in dog prevalence, due to oral transmission from dead infected bugs. Conclusion: Xenointoxication could be a beneficial and novel One Health intervention in regions with high prevalence of T. cruzi and domestic vectors. In regions with low prevalence and domestic or sylvatic vectors, there is potential harm. Field trials should be carefully designed to closely follow treated dogs and include early stopping rules if incidence among treated dogs exceeds that of controls. Author summary: Chagas disease, caused by the parasite Trypanosoma cruzi , is transmitted via triatomine insect vectors. In Latin America, dogs are a common feeding source for triatomine vectors and subsequently an important reservoir of T. cruzi . One proposed intervention to reduce T. cruzi transmission is xenointoxication: treating dogs with oral insecticide to kill triatomine vectors in order to decrease overall T. cruzi transmission. Fluralaner, commonly administered to prevent ectoparasites such as fleas and ticks, is effective under laboratory conditions against the triatomine vectors. One concern with fluralaner treatment is that rapid death of the insect vectors may make the insects more available to oral ingestion by dogs; a more effective transmission pathway than stercorarian, the usual route for T. cruzi transmission. Using a mathematical model, we explored 3 different epidemiologic scenarios: high prevalence endemic disease within a domestic T. cruzi cycle, low prevalence endemic disease within a domestic T. cruzi cycle, and low prevalence endemic disease within a semi-sylvatic T. cruzi cycle. We found a range of beneficial to detrimental effects of fluralaner xenointoxication depending on the epidemiologic scenario. Our results suggest that careful field trials should be designed and carried out before wide scale implementation of fluralaner xenointoxication to reduce T. cruzi transmission.

Assessing and Validating a Model of Study Completion for a Prospective Cohort of Healthy Newborns.

OBJECTIVES: To identify potentially modifiable or actionable factors related to study completion among healthy mother-infant dyads participating in prospective research. PATIENTS/METHODS: We conducted a secondary analysis of completion data from a prospective study on newborn jaundice in the first week of life at a tertiary-care hospital in Philadelphia, PA, from 2015 to 2019. Participation in the original study involved enrollment before newborn discharge and subsequent follow-up for a jaundice assessment between 2 and 6 days of life. For this study, our primary outcome was completion of all study procedures. Associations between predictor variables and the outcome were assessed using bivariate and multivariable analyses. We fit a predictive model of study completion using logistic regression and validated the model using 5-fold cross-validation. RESULTS: Of 501 mother-infant dyads enrolled in the original study, 304 completed the study. Median maternal age was 28 years and 81.8% of mothers delivered via vaginal birth. Study completion was associated with colocation of the study visit with the initial well-child visit (adjusted odds ratio [aOR], 2.99, 95% confidence interval [CI], 2.01-4.46) and provision of an alternate phone number by the participant (aOR, 1.99; 95% CI, 1.34-2.96). The cross-validated model performed similarly to our final predictive model and had an average area under the receiver operating characteristic curve of 0.67 (range, 0.59-0.72), with a sensitivity of 68% and specificity of 60%. CONCLUSIONS: Findings demonstrate the importance of communication and patient-centric approaches for recruitment and retention in newborn research. Future work should incorporate these approaches while continuing to evaluate study retention strategies.

Data Quality in Electronic Health Record Research: An Approach for Validation and Quantitative Bias Analysis for Imperfectly Ascertained Health Outcomes Via Diagnostic Codes.

It is incumbent upon all researchers who use the electronic health record (EHR), including data scientists, to understand the quality of such data. EHR data may be subject to measurement error or misclassification that have the potential to bias results, unless one applies the available computational techniques specifically created for this problem. In this article, we begin with a discussion of data-quality issues in the EHR focusing on health outcomes. We review the concepts of sensitivity, specificity, positive and negative predictive values, and demonstrate how the imperfect classification of a dichotomous outcome variable can bias an analysis, both in terms of prevalence of the outcome, and relative risk of the outcome under one treatment regime (aka exposure) compared to another. This is then followed by a description of a generalizable approach to probabilistic (quantitative) bias analysis using a combination of regression estimation of the parameters that relate the true and observed data and application of these estimates to adjust the prevalence and relative risk that may have existed if there was no misclassification. We describe bias analysis that accounts for both random and systematic errors and highlight its limitations. We then motivate a case study with the goal of validating the accuracy of a health outcome, chronic infection with hepatitis C virus, derived from a diagnostic code in the EHR. Finally, we demonstrate our approaches on the case study and conclude by summarizing the literature on outcome misclassification and quantitative bias analysis.

Perceived Barriers to and Facilitators of Long-Acting Injectable HIV PrEP Use Among Black, Hispanic/Latino, and White Gay, Bisexual, and Other Men Who Have Sex With Men.

Long-acting injectable pre-exposure prophylaxis (LAI-PrEP) was recently approved for HIV prevention as an alternative to daily oral PrEP. We explored preferences and attitudes toward LAI-PrEP among Black, Hispanic/Latino, and White gay, bisexual, and other men who have sex with men (GBM) using focus groups (n = 13) and in-depth interviews (n = 17). Participants expressed differing levels of interest in LAI-PrEP. While important benefits of LAI-PrEP included convenience, provider-facilitated PrEP discussion, and expansion of PrEP options, participants raised concerns about treatment efficacy and side effects, discomfort with needles/injections, cost, and frequency of clinic visits. Our findings highlight ongoing challenges with accessing HIV-prevention tools and provide guidance for developing strategies to enhance LAI-PrEP uptake among GBM.

Accessibility of HIV Services in Philadelphia: Location-Allocation Analysis.

INTRODUCTION: As the first step in the HIV care continuum, timely diagnosis is central to reducing transmission of the virus and ending the HIV epidemic. Studies have shown that distance from a testing site is essential for ease of access to services and educational material. This study shows how location-allocation analysis can be used to improve allocation of HIV testing services utilizing existing publicly available data from 2015 to 2019 on HIV prevalence, testing site location, and factors related to HIV in Philadelphia, Pennsylvania. METHODS: The ArcGIS Location-Allocation analytic tool was used to calculate locations for HIV testing sites using a method that minimizes the distance between demand-point locations and service facilities. ZIP code level demand was initially specified on the basis of the percentage of late HIV diagnoses and in a sensitivity analysis on the basis of a composite of multiple factors. Travel time and distance from demand to facilities determined the facility location allocation. This analysis was conducted from 2021 to 2022. RESULTS: Compared with the 37 facilities located in 20 (43%) Philadelphia ZIP codes, the model proposed reallocating testing facilities to 37 (79%) ZIP codes using percent late diagnoses to define demand. On average, this would reduce distance to the facilities by 65% and travel time to the facilities by 56%. Results using the sensitivity analysis were similar. CONCLUSIONS: A wider distribution of HIV testing services across the city of Philadelphia may reduce distance and travel time to facilities, improve accessibility of testing, and in turn increase the percentage of people with knowledge of their status.

Partisan Polarization of Childhood Vaccination Policies, 1995‒2020.

Objectives. To examine trends in partisan polarization of childhood vaccine bills and the impact of polarization on bill passage in the United States. Methods. We performed content analysis on 1497 US state bills (1995-2020) and obtained voting returns for 228 legislative votes (2011‒2020). We performed descriptive and statistical analyses using 2 measures of polarization. Results. Vote polarization rose more rapidly for immunization than abortion or veterans' affairs bills. Bills in 2019-2020 were more than 7 times more likely to be polarized than in 1995-1996 (odds ratio [OR] = 7.04; 95% confidence interval [CI] = 3.54, 13.99). Bills related to public health emergencies were more polarized (OR = 1.76; 95% CI = 1.13, 2.75). Sponsor polarization was associated with 34% lower odds of passage (OR = 0.66; 95% CI = 0.42, 1.03). Conclusions. State lawmakers were more divided on vaccine policy, but partisan bills were less likely to pass. Bill characteristics associated with lower polarization could signal opportunities for future bipartisanship. Public Health Implications. Increasing partisan polarization could alter state-level vaccine policies in ways that jeopardize childhood immunization rates or weaken responsiveness during public health emergencies. Authorities should look for areas of bipartisan agreement on how to maintain vaccination rates. (Am J Public Health. 2022;112(10):1471-1479. https://doi.org/10.2105/AJPH.2022.306964).

Towards Eliminating Nonmedical Vaccination Exemptions Among School-Age Children.

The increase in childhood vaccine hesitancy and corresponding use of nonmedical exemptions to abstain from vaccination has deleteriously impacted the public's health. This has many in the field calling for widespread elimination of nonmedical school-entry exemptions, as has been done in six states to date: West Virginia, Mississippi, California, New York, Maine, and Connecticut. By eliminating nonmedical exemptions, vaccination rates can be improved, with the corresponding decline in vaccine-preventable disease incidence. Yet the path towards widespread adoption of these policies presents legislative and judicial implications which evolve with the changing political landscape. In this this article, we discuss legislative actions concerning the expansion of exemptions, whether the widespread elimination of nonmedical exemptions would be effective from a practical and legal end, and how the COVID-19 pandemic has influenced such legislation, with specific focus on Delaware.

Disparities of COVID-19 and HIV Occurrence Based on Neighborhood Infection Incidence in Philadelphia, Pennsylvania.

Objectives. To evaluate the occurrence of HIV and COVID-19 infections in Philadelphia, Pennsylvania, through July 2020 and identify ecological correlates driving racial disparities in infection incidence. Methods. For each zip code tabulation area, we created citywide comparison Z-score measures of COVID-19 cases, new cases of HIV, and the difference between the scores. Choropleth maps were used to identify areas that were similar or dissimilar in terms of disease patterning, and weighted linear regression models helped identify independent ecological predictors of these patterns. Results. Relative to COVID-19, HIV represented a greater burden in Center City Philadelphia, whereas COVID-19 was more apparent in Northeast Philadelphia. Areas with a greater proportion of Black or African American residents were overrepresented in terms of both diseases. Conclusions. Although race is a shared nominal upstream factor that conveys increased risk for both infections, an understanding of separate structural, demographic, and economic risk factors that drive the overrepresentation of COVID-19 cases in racial/ethnic communities across Philadelphia is critical. Public Health Implications. Difference-based measures are useful in identifying areas that are underrepresented or overrepresented with respect to disease occurrence and may be able to elucidate effective or ineffective mitigation strategies. (Am J Public Health. 2022;112(3):408-416. https://doi.org/10.2105/AJPH.2021.306538).

State-Level Social and Economic Policies and Their Association With Perinatal and Infant Outcomes.

Policy Points State-level social and economic policies that expand tax credits, increase paid parental leave, raise the minimum wage, and increase tobacco taxes have been demonstrated to reduce adverse perinatal and infant health outcomes. These findings can help prioritize evidence-based legislated policies to improve perinatal and infant outcomes in the United States. CONTEXT: Rates of preterm birth and infant mortality are alarmingly high in the United States. Legislated efforts may directly or indirectly reduce adverse perinatal and infant outcomes through the enactment of certain economic and social policies. METHODS: We conducted a narrative review to summarize the associations between perinatal and infant outcomes and four state-level US policies. We then used a latent profile analysis to create a social and economic policy profile for each state based on the observed policy indicators. FINDINGS: Of 27 articles identified, nine focused on tax credits, eight on paid parental leave, four on minimum wages, and six on tobacco taxes. In all but three studies, these policies were associated with improved perinatal or infant outcomes. Thirty-three states had tax credit laws, most commonly the earned income tax credit (n = 28, 56%). Eighteen states had parental leave laws. Two states had minimum wage laws lower than the federal minimum; 14 were equal to the federal minimum; 29 were above the federal minimum; and 5 did not have a state law. The average state tobacco tax was $1.76 (standard deviation = $1.08). The latent profile analysis revealed three policy profiles, with the most expansive policies in Western and Northeastern US states, and the least expansive policies in the US South. CONCLUSIONS: State-level social and economic policies have the potential to reduce adverse perinatal and infant health outcomes in the United States. Those states with the least expansive policies should therefore consider enacting these evidence-based policies, as they have shown a demonstratable benefit in other states.

Countering the rise of syphilis: A role for doxycycline post-exposure prophylaxis?

Doxycycline post-exposure prophylaxis (PEP) holds the potential to mitigate increasing rates of syphilis among sexual minority men (SMM) in the US yet has received limited attention. Since evaluation of this intervention in actual populations is not currently feasible, we used agent-based models (ABM) to assess the population-level impact of this strategy. We adapted ABM of HIV and HPV transmission, representing a population of 10,230 SMM in Philadelphia, Pennsylvania, US. Parameter inputs were derived from the literature, and ABM outputs during the pre-intervention period were calibrated to local surveillance data. Intervention scenarios varied doxycycline uptake by 20, 40, 60, 80 and 100%, while assuming continued condom use and syphilis screening and treatment. Under each intervention scenario, we incorporated treatment adherence at the following levels: 0, 20, 40, 60, 80 and 100%. Long-term population impact of prophylactic doxycycline was measured using the cumulative incidence over the 10-year period and the percentage of infections prevented attributable to doxycycline at year 10. An uptake scenario of 20% with an adherence level of 80% would reduce the cumulative incidence of infections by 10% over the next decade, translating to 57 fewer cases per 1000 SMM. At year 10, under the same uptake and adherence level, 22% of infections would be prevented due to doxycycline PEP in the instances where condoms were not used or failed. Findings suggest that doxycycline PEP will have a modest impact on syphilis incidence when assuming a reasonable level of uptake and adherence. Doxycycline PEP may be most appropriate as a secondary prevention measure to condoms and enhanced syphilis screening for reducing infections among SMM.

A narrative review on the validity of electronic health record-based research in epidemiology.

Electronic health records (EHRs) are widely used in epidemiological research, but the validity of the results is dependent upon the assumptions made about the healthcare system, the patient, and the provider. In this review, we identify four overarching challenges in using EHR-based data for epidemiological analysis, with a particular emphasis on threats to validity. These challenges include representativeness of the EHR to a target population, the availability and interpretability of clinical and non-clinical data, and missing data at both the variable and observation levels. Each challenge reveals layers of assumptions that the epidemiologist is required to make, from the point of patient entry into the healthcare system, to the provider documenting the results of the clinical exam and follow-up of the patient longitudinally; all with the potential to bias the results of analysis of these data. Understanding the extent of as well as remediating potential biases requires a variety of methodological approaches, from traditional sensitivity analyses and validation studies, to newer techniques such as natural language processing. Beyond methods to address these challenges, it will remain crucial for epidemiologists to engage with clinicians and informaticians at their institutions to ensure data quality and accessibility by forming multidisciplinary teams around specific research projects.