Complexity of the Basic Reproduction Number (R0)

The basic reproduction number (R₀), also called the basic reproduction ratio or rate or the basic reproductive rate, is an epidemiologic metric used to describe the contagiousness or transmissibility of infectious agents. R₀ is affected by numerous biological, sociobehavioral, and environmental factors that govern pathogen transmission and, therefore, is usually estimated with various types of complex mathematical models, which make R₀ easily misrepresented, misinterpreted, and misapplied. R₀ is not a biological constant for a pathogen, a rate over time, or a measure of disease severity, and R₀ cannot be modified through vaccination campaigns. R₀ is rarely measured directly, and modeled R₀ values are dependent on model structures and assumptions. Some R₀ values reported in the scientific literature are likely obsolete. R₀ must be estimated, reported, and applied with great caution because this basic metric is far from simple.

Early evidence from South Carolina's Medicare-Medicaid dual-eligible financial alignment initiative: an observational study to understand who enrolled, and whether the program improved health?

Background

Individuals dually eligible for Medicare and Medicaid coverage are among the sickest patients in the United States. Prior literature has identified a lack of care coordination or even conflicts of interest between the two programs as barriers to more efficient care and better health outcomes among dual-eligibles. The purpose of this study is to assess characteristics of dual eligibles who participated in South Carolina’s 2015 voluntary Medicare-Medicaid financial alignment demonstration project, and to evaluate whether their participation led to better observable health outcomes.

Methods

We obtained all inpatient and emergency department visits, and all Medicaid outpatient visits of individuals identified as Medicare-Medicaid dual eligibles from 2011 to 2016 from South Carolina’s Revenue and Fiscal Affairs Office. We employed logistic regressions to assess the characteristics of participants and quitters in the Medicare-Medicaid financial alignment demonstration project. To evaluate the impact of participation on health outcomes, we used an event study analysis that examines trends in outcomes over time, with participation in the demonstration project as the triggering event, and a difference-in-differences methodology that compares changes in health outcomes before and after participation in the demonstration project compared with a control group.

Results

Urban patients, female patients, and patients with heart problems, social and mental disorders, and importantly, patients with multiple comorbidities (as indicated by a higher Charlson comorbidity index) are less likely to join South Carolina’s demonstration project. Once having joined, female patients and patients with a higher Charlson index appear to be more likely to quit. Those who joined did not appear to enjoy better health outcomes in the short time frame.

Conclusions

Policy makers should explore and address reasons why dual eligibles with complex health problems hesitate to join the alignment project, and continue to monitor whether such a program improves health given that a prolonged period of exposure to the program may be required to achieve better health among the nation’s most vulnerable patients.

IGFBP2 promotes vasculogenic mimicry formation via regulating CD144 and MMP2 expression in glioma

Vasculogenic mimicry (VM) refers to the fluid-conducting channels formed by aggressive tumor cells rather than endothelial cells (EC) with elevated expression of genes associated with vascularization. VM has been considered as one of the reasons that glioblastoma becomes resistant to anti-VEGF therapy. However, the molecular basis underlying VM formation remains unclear. Here we report that the insulin-like growth factor-binding protein 2 (IGFBP2) acts as a potent factor to enhance VM formation in glioma. Evidence showed that elevated IGFBP2 expression was positively related with VM formation in patients with glioma. Enforced expression of IGFBP2 increased network formation of glioma cells in vitro by activating CD144 and MMP2 (Matrix Metalloproteinase 2). U251 cells with stable knockdown of IGFBP2 led to decreased VM formation and tumor progression in orthotopic mouse model. Mechanistically, IGFBP2 interacts with integrin α5 and β1 subunits and augments CD144 expression in a FAK/ERK pathway-dependent manner. Luciferase reporter and ChIP assay suggested that IGFBP2 activated the transcription factor SP1, which could bind to CD144 promoter. Thus, IGFBP2 acts as a stimulator of VM formation in glioma cells via enhancing CD144 and MMP2 expression.

Precision medicine and sharing medical data in real time: opportunities and barriers

Sharing massive amounts of medical data is critical to precision medicine. The California Department of Public Health recently started to partner with certain hospitals in the state to better understand cancer trends by collecting and securely sending standardized cancer data directly to the California Cancer Registry. This initiative is the first of its kind in the United States. This has afforded the cancer registry the opportunity to perform real-time surveillance on data reported via participating hospitals, and researchers can use advanced methods to analyze these data. Other states are likely to follow California's lead. However, there are barriers to increased data-sharing efforts. How these barriers can be addressed to facilitate data sharing while protecting individual privacy, reducing the risk of data misuse, and enhancing public trust becomes critical as precision medicine moves forward.

FDA's regulatory shift on tobacco control

In July 2017, the Food and Drug Administration (FDA) announced that it wants to reduce the nicotine in cigarettes to make them less addictive. Also, it is delaying for several years a key regulation affecting cigars and e-cigarettes, including flavored vaping products that tend to appeal to younger consumers. Specifically, it postponed the requirement that such products be approved by the agency. Both actions are part of a comprehensive plan to eventually wean smokers off conventional cigarettes and steer them toward less harmful alternative forms of nicotine. With its new approach to the fight against smoking, the FDA has unquestionably made great strides toward more effectively addressing the prevalence of related deaths and diseases in the U.S. However, much important work must be undertaken before this ultimate goal can be accomplished. For instance, further research into long-term effects of e-cigarettes must be conducted before these products can truly be seen as safer alternatives to combustible cigarettes. Additionally, public education is necessary to inform smokers about the range of tobacco products available and the actual harms associated with their use. Finally, the agency might have to work alongside the powerful tobacco industry to minimize potential legal challenges and to convince businesses that a shift to low-nicotine products and e-cigarettes is best for their future success and for the health of the American citizenry.

Immunization Mandates, Vaccination Coverage, and Exemption Rates in the United States

Background

Vaccination coverage among children entering kindergarten in the United States is high, but interstate variations exist. The relationship between state immunization laws and vaccination coverage has not been fully assessed. We evaluated associations of state laws on both measles, mumps, and rubella (MMR) and diphtheria, tetanus, and pertussis (DTaP) vaccination coverage and exemptions to school immunization requirements.

Methods

We conducted a retrospective, longitudinal analysis of the effect of state immunization laws on vaccination coverage and exemptions among US kindergarteners from SY 2008 to SY 2014. The primary outcome measures were state-level kindergarten entry vaccination coverage rates for 2-dose MMR and 4-dose DTaP vaccines. Secondary outcome measures included rates of state-level exemptions (ie, medical, religious, philosophical) to school immunization requirements.

Results

We found that state policies that refer to Advisory Committee on Immunization Practices recommendations were associated with 3.5% and 2.8% increases in MMR and DTaP vaccination rates. Health Department–led parental education was associated with 5.1% and 4.5% increases in vaccination rates. Permission of religious and philosophical exemptions was associated with 2.3% and 1.9% decreases in MMR and DTaP coverage, respectively, and a 1.5% increase in both total exemptions and nonmedical exemptions, respectively.

Conclusions

We found higher vaccination coverage and lower nonmedical exemption rates for MMR and DTaP vaccines in states adopting Advisory Committee on Immunization Practices guidelines for school entry. Adherence to these best practices was a successful strategy to increase vaccination coverage and reduce vaccination exemptions.

Examining the spatiotemporal evolution of vaccine refusal: nonmedical exemptions from vaccination in California, 2000-2013

BACKGROUND

Vaccine hesitancy continues to be an issue throughout the United States, as numerous vaccine hesitant parents are choosing to exempt their children from school-entry vaccination requirements for nonmedical reasons, despite the safety and effectiveness of vaccines. We conduct an analysis of how vaccine refusal, measured by the use of nonmedical exemptions (based on personal or religious beliefs) from vaccination (NMEs), evolved across space and over time in California.

METHODS

Using school-entry data from the California Department of Public Health, we examined NMEs for students entering kindergarten in California from 2000 to 2013. We conduct global and local spatial autocorrelation analysis to determine whether NME use became more geographically clustered over the study period and whether the location of local clusters of high use were temporally stable. We conducted a grouping analysis that identified the general temporal trends in NME use over the time period.

RESULTS

The use of NMEs increased from 0.73% of all kindergarteners in 2000 to 3.09% in 2013 and became more geographically clustered over the study period. Local geographic clusters of high use were relatively isolated early in the study period, but expanded in size over time. The grouping analysis showed that regions with high NME use early in the study period were generally few (15% of all US Census tracts) and relatively isolated. Regions that had low initial NME use and moderate to large increases over the study period were located in close proximity to the initial high use regions. The grouping analysis also showed that roughly half of all tracts had 0% or very low NME use throughout the study period.

CONCLUSIONS

We found an observable spatial structure to vaccine refusal and NME use over time, which appeared to be a self-reinforcing process, as well as a spatially diffusive process. Importantly, we found evidence that use of NMEs in the initially isolated regions appeared to stimulate vaccine refusal in geographically proximal regions. Thus, our results suggest that efforts aimed at decreasing future NME use may be most effective if they target regions where NME use is already high, as well as the nearby regions.

It could have been much worse: The Minnesota measles outbreak of 2017

In 2017, Minnesota battled its largest measles outbreak in nearly 30 years, with 79 cases, most of them Somali-American children. In this study, we gathered vaccination and enrollment data for incoming kindergarteners in Minnesota over fall 2012-2016 from the Minnesota Department of Health. We also gathered the number of measles cases by county in 2017. We found that MMR coverage has substantial variation across districts and district types. The minimum MMR coverage is 58.3% and the maximum is 100%. Private schools, which represent approximately six percent of Minnesota's kindergarten enrollment, have a substantially lower coverage rate, with an overall coverage of 83.00%. The 2017 outbreak was relatively isolated. However, the MMR coverage data suggests that other communities could have been at risk given their geographic proximity to the outbreak and modest coverage rates.

Damage to epitaxial GaN layer on Al2O3 by 290-MeV 238U32+ ions irradiation

Micro-structural characteristics and electrical properties of an n-type GaN epilayer on Al₂O₃ irradiated by 290-MeV ²³⁸U³²⁺ ions to various fluences were investigated using atomic force microscopy (AFM), scanning electron microscopy (SEM), high-resolution X-ray diffraction (HRXRD), and Raman scattering spectroscopy. AFM images show that the nano-hillocks generated, and the diameter and density of the nano-hillocks, increase obviously with increasing ion fluence, accompanied by an increase in surface roughness. SEM images display that the Al, O, and C elements appear on the GaN surface, along with a spiral-like, layered volcanic-cone structure formed at the highest-fluence irradiation. HRXRD reveals that the dislocation density increases, as the lattices gradually expand, and that Ga₂O₃ was produced with increasing ion fluence. Raman scattering spectra show that no N and Ga vacancies were produced, the free-carrier concentration decreases, while its mobility first increases and then exhibits a significant reduction with increasing ion fluence.

Mapping integration of midwives across the United States: Impact on access, equity, and outcomes

METHODS

Our multidisciplinary team examined published regulatory data to inform a 50-state database describing the environment for midwifery practice and interprofessional collaboration. Items (110) detailed differences across jurisdictions in scope of practice, autonomy, governance, and prescriptive authority; as well as restrictions that can affect patient safety, quality, and access to maternity providers across birth settings. A nationwide survey of state regulatory experts (n = 92) verified the 'on the ground' relevance, importance, and realities of local interpretation of these state laws. Using a modified Delphi process, we selected 50/110 key items to include in a weighted, composite Midwifery Integration Scoring (MISS) system. Higher scores indicate greater integration of midwives across all settings. We ranked states by MISS scores; and, using reliable indicators in the CDC-Vital Statistics Database, we calculated correlation coefficients between MISS scores and maternal-newborn outcomes by state, as well as state density of midwives and place of birth. We conducted hierarchical linear regression analysis to control for confounding effects of race.

RESULTS

MISS scores ranged from lowest at 17 (North Carolina) to highest at 61 (Washington), out of 100 points. Higher MISS scores were associated with significantly higher rates of spontaneous vaginal delivery, vaginal birth after cesarean, and breastfeeding, and significantly lower rates of cesarean, preterm birth, low birth weight infants, and neonatal death. MISS scores also correlated with density of midwives and access to care across birth settings. Significant differences in newborn outcomes accounted for by MISS scores persisted after controlling for proportion of African American births in each state.

CONCLUSION

The MISS scoring system assesses the level of integration of midwives and evaluates regional access to high quality maternity care. In the United States, higher MISS Scores were associated with significantly higher rates of physiologic birth, less obstetric interventions, and fewer adverse neonatal outcomes.

Change in Medical Exemptions From Immunization in California After Elimination of Personal Belief Exemptions

This study evaluates the statewide change in medical exemptions in the first year under California Senate bill 277 and if medical exemptions increased in regions with high personal belief exemption use prior to its enactment.

Tale of Two Erythropoiesis-Stimulating Agents: Utilization, Dosing, Litigation, and Costs of Darbepoetin and Epoetin Among South Carolina Medicaid-Covered Patients With Cancer and Chemotherapy-Induced Anemia

PURPOSE

The US Food and Drug Administration (FDA) has approved epoetin and darbepoetin for chemotherapy-induced anemia (CIA). Approved epoetin and darbepoetin dosing schedules were three times per week and weekly, respectively, although off-label, less frequent scheduling was common. In 2004, 2007, and 2008, a US Food and Drug Administration Advisory Committees warned of risks associated with erythropoiesis-stimulating agents. During this period, lawsuits alleging illegal darbepoetin marketing practices have concluded, resulting in $1.1 billion in fines and settlements and one criminal conviction. No prior study, to our knowledge, has reported on the use of darbepoetin versus epoetin for CIA.

METHODS

We evaluated the dosing, utilization, and costs of erythropoiesis-stimulating agents among 3,761 South Carolina Medicaid patients with CIA.

RESULTS

Epoetin and darbepoetin utilization rates were 22% and 28% in 2003, 10% and 33% in 2007, and 3% and 7% in 2010, respectively. Mean per-patient per-administration epoetin and darbepoetin doses were 40,983 IU and 191 µg, respectively, in 2003 and 47,753 IU and 369 µg, respectively, in 2010. Mean monthly patient costs for epoetin and darbepoetin were $1,030 and $981, respectively, in 2003 and $932 and $1,352, respectively, in 2010. Epoetin use decreased steadily between 2002 and 2010; darbepoetin use increased steadily between 2003 and 2007 and then decreased steadily thereafter. Per-patient dosing of darbepoetin, but not epoetin, increased steadily between 2003 and 2010, and monthly per-patient epoetin costs decreased 3% while the per-patients costs of darbepoetin increased 30% between 2003 and 2010.

CONCLUSION

To our knowledge, our findings are the first data reporting on epoetin versus darbepoetin use for CIA and support recently concluded lawsuits involving allegations of illegal marketing practices of the manufacturer of darbepoetin.