The Affordability Of Individual-Market Health Insurance In California Under The American Rescue Plan Act, 2021.

In 2021 the American Rescue Plan Act increased premium subsidies for people purchasing insurance from the Affordable Care Act Marketplaces and provided zero-premium Marketplace plans that covered 94 percent of medical care costs (silver 94 plans) to recipients of unemployment compensation. Using data on adult enrollees in on- and off-Marketplace individual plans in California in 2021, we found that 41 percent reported incomes at or below 400 percent of the federal poverty level and that 39 percent reported living in households receiving unemployment compensation. Overall, 72 percent of enrollees reported having no difficulty paying premiums, and 76 percent reported that out-of-pocket expenses did not affect their seeking of medical care. The majority of enrollees eligible for plans with cost-sharing subsidies were enrolled in Marketplace silver plans (56-58 percent). Many of these enrollees, however, may have missed opportunities for premium or cost-sharing subsidies: 6-8 percent enrolled in off-Marketplace plans and were more likely to have difficulty paying premiums than those in Marketplace silver plans, and more than one-quarter enrolled in Marketplace bronze plans and were more likely to delay care because of cost than those in Marketplace silver plans. In the coming era of expanded Marketplace subsidies under the Inflation Reduction Act of 2022, helping consumers identify high-value and subsidy-eligible plans could mitigate remaining affordability problems.

Comparing The Effects Of Nudges And Automatic Plan Switching On Choice Errors Among Low-Income Marketplace Enrollees.

During the 2022 open enrollment period in California's Affordable Care Act Marketplace, we tested two interventions designed to reduce choice errors among low-income households enrolled in bronze plans that were eligible for zero-premium cost-sharing reduction (CSR) silver plans with more generous benefits. A randomized controlled trial nudge intervention used letter and email reminders to encourage consumers to switch plans, and a quasi-experimental crosswalk intervention automatically enrolled eligible households from bronze plans into zero-premium CSR silver plans with the same insurers and provider networks. The nudge intervention led to a statistically significant 2.3-percentage-point (26 percent) increase in CSR silver plan take-up relative to the control group, but nearly 90 percent of households remained in nonsilver plans. The automatic crosswalk intervention resulted in an 83.0-percentage-point (822 percent) increase in CSR silver plan take-up compared with the control group, with more than 90 percent of households enrolled in CSR silver plans. Our findings can inform health policy debates on the relative effectiveness of different approaches to reducing choice errors among low-income households in the Affordable Care Act Marketplaces.

Personalized Letters And Emails Increased Marketplace Enrollment Among Households Eligible For Zero-Premium Plans.

More than one million low-income uninsured people are eligible for zero-premium cost-sharing reduction (CSR) silver plans through the Affordable Care Act (ACA) Marketplaces. However, many are not aware of these options, and Marketplaces are uncertain about what types of informational messages will increase take-up. In 2021 and 2022, before and after the introduction of zero-premium plans in Covered California, California's individual ACA Marketplace, we conducted two randomized controlled trials among low-income households that submitted an application and were found eligible for $1 per month or zero-premium coverage but were not yet enrolled. We tested the effect of personalized letters and emails that informed households that they were eligible for a $1 per month or zero-premium CSR silver plan. Across both settings, low-cost personalized outreach increased rates of ACA enrollment, CSR silver plan take-up, and $1 per month or zero-premium CSR silver plan take-up. But even with free or nearly free coverage options, absolute rates of enrollment remained low, suggesting that more resource-intensive efforts are needed to help prospective enrollees overcome nonprice barriers.

Assessment of Churn in Coverage Among California's Health Insurance Marketplace Enrollees.

Importance: Individual health insurance marketplaces established through the Affordable Care Act of 2010 (ACA) fill a critical gap for those who lack other coverage options. The high degree of coverage turnover, or churn, has raised concerns about affordability and strategic behavior on the part of individuals to sign up only when they need care. Objective: To assess the role of California's ACA marketplaces in the broader health care landscape by understanding enrollment tenure and churn. Design, Setting, and Participants: This cross-sectional study analyzed survey data from a representative, probability-based sample of enrollees in California's ACA marketplace, Covered California, collected immediately after the open enrollment periods in 2018, 2019, and 2021. Administrative data from Covered California from January 1, 2014, to December 31, 2021, were used to analyze marketplace tenure. Survey data included 9571 heads of households aged 18 to 64 years who were newly enrolled or had recently terminated their plan, directly drawn from Covered California's administrative records. Administrative data included individuals up to age 65 years who enrolled in the marketplace during 2014 to 2021. Exposures: New enrollment in or termination from health care coverage through California's ACA marketplace. Main Outcomes and Measures: Enrollment tenure in California's ACA marketplace, sources of coverage prior to enrolling and after terminating coverage, and demographic or plan characteristics associated with the decision to go uninsured. Results: Median (IQR) length of coverage among 5.4 million enrollees (mean [SD] age, 38 [16] years; 17% Asian American/Native Hawaiian or other Pacific Islander, 2.5% Black or African American, 23% Latino [response options were Hispanic, Spanish, or Latino origin], 29% White, 7.5% categorized as other [including American Indian/Alaskan Native, multiple races, and other], and 21% of unknown race or ethnicity) was 14 (6-35) months, and 41% to 46% of enrollees disenrolled within 1 year, with substantial variation by subgroups. Despite this churn, only 14% (95% CI, 12%-15%) of 6474 terminating members surveyed across 3 years (2018, 2019, and 2021) reported being uninsured after leaving the marketplace, with the rest moving to job-based coverage or Medicaid. Most of those surveyed (mean [SE] percentage, 56% [0.016] individuals) reported having had employer-sponsored insurance or Medicaid prior to enrolling in the marketplace. Among subsidized renewal candidates, Latino candidates were 1.5 percentage points (95% CI, 0.8-2.3 percentage points) more likely to go uninsured compared with White candidates, and those with no expected physician visits in the coming year were 4.8 percentage points (95% CI, 2.4-7.2 percentage points) more likely to go uninsured vs those who expected physician visits. Conclusions and Relevance: The results of this cross-sectional study of coverage churn found that ACA marketplaces served 2 distinct types of individuals, long-term enrollees but, more often, individuals with short-term-coverage needs due to a change in eligibility for other insurance. These results suggest that marketplaces are smoothing coverage disruptions and that policies to reduce gaps in coverage should be designed with this in mind.

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.

Estimated Impact of Screening on Gonorrhea Epidemiology in the United States: Insights From a Mathematical Model.

The burden of gonorrhea infections in the United States is high. There are marked disparities by race/ethnicity and sexual orientation. We quantified the impact of screening and treatment on gonorrhea rates in the US population aged 15 to 39 years for the period 2000 to 2015 and estimated the impact that alternative screening strategies might have had over the same period. METHODS: We developed a national-level transmission model that divides the population by race/ethnicity, preferred gender of sex partners, age, gender, and sexual activity level. We compared our fitted model ("base case") to 4 alternative strategies: (i) no screening, (ii) full adherence to current screening guidelines, (iii) annual universal screening, or (iv) enhanced screening in groups with the highest infection burden. Main outcomes were incidence, infections averted, and incidence rate ratios by race/ethnicity. Mean values and 95% credible intervals were calculated from 1000 draws from parameter posterior distributions. RESULTS: The calibrated model reproduced observed trends in gonorrhea, including disparities in infection burden by race/ethnicity. We estimated that screening for gonorrhea from 2000 to 2015 averted 30% (95% credible intervals, 18-44%) of total infections that would otherwise have occurred. All alternative active screening strategies were estimated to further reduce, but not eliminate, gonorrhea infections relative to the base case, with differential impacts on the subpopulations of interest. CONCLUSIONS: Our model results suggest that screening has reduced gonorrhea incidence in the US population. Additional reductions in infection burden may have been possible over this period with increased screening, but elimination was unlikely.

Prospects for Tuberculosis Elimination in the United States: Results of a Transmission Dynamic Model.

We estimated long-term tuberculosis (TB) trends in the US population and assessed prospects for TB elimination. We used a detailed simulation model allowing for changes in TB transmission, immigration, and other TB risk determinants. Five hypothetical scenarios were evaluated from 2017 to 2100: 1) maintain current TB prevention and treatment activities (base case); 2) provision of latent TB infection testing and treatment for new legal immigrants; 3) increased uptake of latent TB infection screening and treatment among high-risk populations, including a 3-month isoniazid-rifapentine regimen; 4) improved TB case detection; and 5) improved TB treatment quality. Under the base case, we estimate that by 2050, TB incidence will decline to 14 cases per million, a 52% (95% posterior interval (PI): 35, 67) reduction from 2016, and 82% (95% posterior interval: 78, 86) of incident TB will be among persons born outside of the United States. Intensified TB control could reduce incidence by 77% (95% posterior interval: 66, 85) by 2050. We predict TB may be eliminated in US-born but not non-US-born persons by 2100. Results were sensitive to numbers of people entering the United States with latent or active TB, and were robust to alternative interpretations of epidemiologic evidence. TB elimination in the United States remains a distant goal; however, strengthening TB prevention and treatment could produce important health benefits.

Progression from latent infection to active disease in dynamic tuberculosis transmission models: a systematic review of the validity of modelling assumptions.

Mathematical modelling is commonly used to evaluate infectious disease control policy and is influential in shaping policy and budgets. Mathematical models necessarily make assumptions about disease natural history and, if these assumptions are not valid, the results of these studies can be biased. We did a systematic review of published tuberculosis transmission models to assess the validity of assumptions about progression to active disease after initial infection (PROSPERO ID CRD42016030009). We searched PubMed, Web of Science, Embase, Biosis, and Cochrane Library, and included studies from the earliest available date (Jan 1, 1962) to Aug 31, 2017. We identified 312 studies that met inclusion criteria. Predicted tuberculosis incidence varied widely across studies for each risk factor investigated. For population groups with no individual risk factors, annual incidence varied by several orders of magnitude, and 20-year cumulative incidence ranged from close to 0% to 100%. A substantial proportion of modelled results were inconsistent with empirical evidence: for 10-year cumulative incidence, 40% of modelled results were more than double or less than half the empirical estimates. These results demonstrate substantial disagreement between modelling studies on a central feature of tuberculosis natural history. Greater attention to reproducing known features of epidemiology would strengthen future tuberculosis modelling studies, and readers of modelling studies are recommended to assess how well those studies demonstrate their validity.

The Use of Mathematical Models of Chlamydia Transmission to Address Public Health Policy Questions: A Systematic Review.

BACKGROUND: Mathematical models of chlamydia transmission can help inform disease control policy decisions when direct empirical evaluation of alternatives is impractical. We reviewed published chlamydia models to understand the range of approaches used for policy analyses and how the studies have responded to developments in the field. METHODS: We performed a literature review by searching Medline and Google Scholar (up to October 2015) to identify publications describing dynamic chlamydia transmission models used to address public health policy questions. We extracted information on modeling methodology, interventions, and key findings. RESULTS: We identified 47 publications (including two model comparison studies), which reported collectively on 29 distinct mathematical models. Nine models were individual-based, and 20 were deterministic compartmental models. The earliest studies evaluated the benefits of national-level screening programs and predicted potentially large benefits from increased screening. Subsequent trials and further modeling analyses suggested the impact might have been overestimated. Partner notification has been increasingly evaluated in mathematical modeling, whereas behavioral interventions have received relatively limited attention. CONCLUSIONS: Our review provides an overview of chlamydia transmission models and gives a perspective on how mathematical modeling has responded to increasing empirical evidence and addressed policy questions related to prevention of chlamydia infection and sequelae.