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As part of the Pathology, Alzheimer’s and Related Dementias Study, we conducted uniform structured interviews with knowledgeable informants (72% children) of 1,493 older (age > 65) Brazilian decedents.
The interview included measures of social isolation (number of family and friends in at least monthly contact with decedent), emotional isolation (short form of UCLA Loneliness Scale), and major depression plus the informant portion of the Clinical Dementia Rating Scale to diagnose dementia and its precursor, mild cognitive impairment (MCI).
Decedents had a median social network size of 8.0 (interquartile range = 9.0) and a median loneliness score of 0.0 (interquartile range = 1.0). On the Clinical Dementia Rating Scale, 947 persons had no cognitive impairment, 122 had MCI, and 424 had dementia. In a logistic regression model adjusted for age, education, sex, and race, both smaller network size (odds ratio [OR] = 0.975; 95% confidence interval [CI]: 0.962, 0.989) and higher loneliness (OR = 1.145; 95% CI: 1.060, 1.237) were associated with higher likelihood of dementia. These associations persisted after controlling for depression (present in 10.4%) and did not vary by race. After controlling for depression, neither network size nor loneliness was related to MCI.
Social and emotional isolation are associated with higher likelihood of dementia in older black and white Brazilians.
We evaluated the ability of an ultraviolet-C (UV-C) room decontamination device to kill Candida auris and C. albicans. With an organic challenge (fetal calf serum), the UV-C device demonstrated the following log10 reductions for C. auris of 4.57 and for C. albicans of 5.26 with direct line of sight, and log10 reductions for C. auris of 2.41 and for C. ablicans of 3.96 with indirect line of sight.
This case study was prompted by the identification, in observations and in discussion with the normal class teacher, of pupil demotivation and disaffection during Latin lessons, and the fact that this represented a considerable barrier to attainment and progress. My observation of this phenomenon coincided with Year 9 submitting their GCSE options. The combination of apparently ambiguous attitudes towards the subject and the fact that these attitudes were being brought to the fore explicitly because of the options choices drew my attention to pupil perceptions of the subject. It seemed to me that understanding the way in which pupils perceive the subject might be instructive for my own teaching practice, allowing me to better understand what pupils enjoy about the subject, what they find difficult, what enthuses them and what turns them off. Furthermore, the place of Latin within schools in general, and the particular school in which I conducted this study, is not something that should be taken for granted. It seemed to me, therefore, that this case study might provide some insight into whether Latin is a subject that young people feel is relevant and perhaps might offer some insight into what can allow Latin to have as inclusive an appeal as possible.
To describe a pilot project infection prevention and control (IPC) assessment conducted in skilled nursing facilities (SNFs) in New York State (NYS) during a pivotal 2-week period when the region became the nation’s epicenter for coronavirus disease 2019 (COVID-19).
A telephone and video assessment of IPC measures in SNFs at high risk or experiencing COVID-19 activity.
SNFs in 14 New York counties, including New York City.
A 3-component remote IPC assessment: (1) screening tool; (2) telephone IPC checklist; and (3) COVID-19 video IPC assessment (ie, “COVIDeo”).
In total, 92 SNFs completed the IPC screening tool and checklist: 52 (57%) were conducted as part COVID-19 investigations, and 40 (43%) were proactive prevention-based assessments. Among the 40 proactive assessments, 14 (35%) identified suspected or confirmed COVID-19 cases. COVIDeo was performed in 26 (28%) of 92 assessments and provided observations that other tools would have missed: personal protective equipment (PPE) that was not easily accessible, redundant, or improperly donned, doffed, or stored and specific challenges implementing IPC in specialty populations. The IPC assessments took ∼1 hour each and reached an estimated 4 times as many SNFs as on-site visits in a similar time frame.
Remote IPC assessments by telephone and video were timely and feasible methods of assessing the extent to which IPC interventions had been implemented in a vulnerable setting and to disseminate real-time recommendations. Remote assessments are now being implemented across New York State and in various healthcare facility types. Similar methods have been adapted nationally by the Centers for Disease Control and Prevention.
ABSTRACT IMPACT: Chronic kidney disease (CKD) affects ˜15% of the US population and the majority of patients are diagnosed too late to benefit from early intervention. We are developing a new diagnostic imaging tool (RadioCF-PET) for the kidney to enable early detection of diseases and to monitor overall kidney health. OBJECTIVES/GOALS: Nephron mass, or the number of functioning nephrons, is a measure of the functional capacity of the kidney. RadioCF-PET may enable early detection of nephron loss in patients with or at risk of CKD before changes are clinically detectable, facilitating early interventions to improve outcomes in these patients. METHODS/STUDY POPULATION: RadioCF-PET, labeled with Cu-64, has the advantage of using sub pharmacological doses for imaging, carrying low risk and can be used with the FDA’s exploratory IND (eIND) mechanism for early in human testing. We are developing the technology to be used in pre-eIND toxicology and pharmacology studies. We are also developing other aspects of translational science to propel this technology toward translation, including: market analysis, critical path to market, customer discovery, and commercialization strategy. RESULTS/ANTICIPATED RESULTS: Milestone 1: Apply technology in mouse model study and in human kidneys rejected for transplant. Anticipated Result 1: PET signal from RadioCF-PET correlates with glomerular density in healthy and diseased model male mice (R2 = 0.98). RadioCF-PET signal correlates with glomerular number in a donated human kidney (R2= 0.78). Milestone 2: Application to federal funding (STTR) and gap funding mechanisms to enable pre-eIND studies. Anticipated Result 1: Application for funding will aid to clarify and validate our market analysis and commercialization strategy. Milestone 3: Continued research and development with the technology in new studies. Other Anticipated Results: Future work with RadioCF-PET will enhance technology performance in preparation for pre-eIND studies. DISCUSSION/SIGNIFICANCE OF FINDINGS: We foresee a large clinical and commercial potential for RadioCF-PET to provide precise, early monitoring in patients at risk for or with CKD. The two biggest hurdles for clinical translation are validating safety and proving efficacy. This work targets both issues to facilitate RadioCF-PET toward clinical translation.
This SHEA white paper identifies knowledge gaps and challenges in healthcare epidemiology research related to coronavirus disease 2019 (COVID-19) with a focus on core principles of healthcare epidemiology. These gaps, revealed during the worst phases of the COVID-19 pandemic, are described in 10 sections: epidemiology, outbreak investigation, surveillance, isolation precaution practices, personal protective equipment (PPE), environmental contamination and disinfection, drug and supply shortages, antimicrobial stewardship, healthcare personnel (HCP) occupational safety, and return to work policies. Each section highlights three critical healthcare epidemiology research questions with detailed description provided in supplementary materials. This research agenda calls for translational studies from laboratory-based basic science research to well-designed, large-scale studies and health outcomes research. Research gaps and challenges related to nursing homes and social disparities are included. Collaborations across various disciplines, expertise and across diverse geographic locations will be critical.
In recent years, a variety of efforts have been made in political science to enable, encourage, or require scholars to be more open and explicit about the bases of their empirical claims and, in turn, make those claims more readily evaluable by others. While qualitative scholars have long taken an interest in making their research open, reflexive, and systematic, the recent push for overarching transparency norms and requirements has provoked serious concern within qualitative research communities and raised fundamental questions about the meaning, value, costs, and intellectual relevance of transparency for qualitative inquiry. In this Perspectives Reflection, we crystallize the central findings of a three-year deliberative process—the Qualitative Transparency Deliberations (QTD)—involving hundreds of political scientists in a broad discussion of these issues. Following an overview of the process and the key insights that emerged, we present summaries of the QTD Working Groups’ final reports. Drawing on a series of public, online conversations that unfolded at www.qualtd.net, the reports unpack transparency’s promise, practicalities, risks, and limitations in relation to different qualitative methodologies, forms of evidence, and research contexts. Taken as a whole, these reports—the full versions of which can be found in the Supplementary Materials—offer practical guidance to scholars designing and implementing qualitative research, and to editors, reviewers, and funders seeking to develop criteria of evaluation that are appropriate—as understood by relevant research communities—to the forms of inquiry being assessed. We dedicate this Reflection to the memory of our coauthor and QTD working group leader Kendra Koivu.1
To describe epidemiologic and genomic characteristics of a severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreak in a large skilled-nursing facility (SNF), and the strategies that controlled transmission.
Design, setting, and participants:
This cohort study was conducted during March 22–May 4, 2020, among all staff and residents at a 780-bed SNF in San Francisco, California.
Contact tracing and symptom screening guided targeted testing of staff and residents; respiratory specimens were also collected through serial point prevalence surveys (PPSs) in units with confirmed cases. Cases were confirmed by real-time reverse transcription–polymerase chain reaction testing for SARS-CoV-2, and whole-genome sequencing (WGS) was used to characterize viral isolate lineages and relatedness. Infection prevention and control (IPC) interventions included restricting from work any staff who had close contact with a confirmed case; restricting movement between units; implementing surgical face masking facility-wide; and the use of recommended PPE (ie, isolation gown, gloves, N95 respirator and eye protection) for clinical interactions in units with confirmed cases.
Of 725 staff and residents tested through targeted testing and serial PPSs, 21 (3%) were SARS-CoV-2 positive: 16 (76%) staff and 5 (24%) residents. Fifteen cases (71%) were linked to a single unit. Targeted testing identified 17 cases (81%), and PPSs identified 4 cases (19%). Most cases (71%) were identified before IPC interventions could be implemented. WGS was performed on SARS-CoV-2 isolates from 4 staff and 4 residents: 5 were of Santa Clara County lineage and the 3 others were distinct lineages.
Early implementation of targeted testing, serial PPSs, and multimodal IPC interventions limited SARS-CoV-2 transmission within the SNF.
Immunocompromised patients are at risk for infections due to above-ceiling activities in hospitals. Mobile dust-containment carts are available as environmental controls, but no published data support their efficacy. Using microbial air sampling and particle counts, we provide evidence of reduced risk of fungal exposure during open ceiling activities.
Background: Infection prevention efforts are complex, and sustaining reductions is even more challenging. At the UNC Medical Center, multidisciplinary hospital-wide work groups implement quality improvement initiatives to prevent healthcare-associated infections. The first and most successful initiative has been our catheter-associated urinary tract infection (CAUTI) prevention effort, which started in 2014. The program led to initial dramatic reductions, with continued reductions in CAUTI rates each year since then. Methods: A multidisciplinary workgroup formed in 2014 developed an evidence-based CAUTI prevention bundle and partnered with the nursing staff in 2015–2016 to implement practice changes as part of our hospital’s quality improvement “Spread of Innovations” model. These changes included (1) creation of a 2-person catheter-insertion checklist; (2) insertion skills validation for all nursing staff and nursing assistants; (3) standardization of a maintenance protocol and subsequent education and skills validation with nurses and nurse assistants; and (4) peer audits of urinary catheter maintenance. Additional initiatives implemented over the past 5 years include (1) routine resident education on CAUTI prevention; (2) annual nurse competencies to reinforce skills around CAUTI prevention; (3) introduction of products (eg, PureWick) as alternatives to indwelling catheters; (4) diagnostic stewardship efforts; (5) revisions to the electronic medical record; and (6) efforts to encourage removal of unnecessary catheters such as the “nurse-driven conversation” and Trial of Void. Results: Our CAUTI rates decreased 65% from 2.94 per 1,000 catheter days in the baseline period of 2014 to 1.02 in 2018. In our ICUs (excluding the neonatal ICU), the rate dropped 75% from 4.30 in 2014 to 1.08 per 1,000 catheter days in 2018. Conclusions: We attribute our continued reductions and successful sustainment of low CAUTI rates to several factors. First, the use of a multidisciplinary team was critical to obtaining buy-in from key stakeholders including nursing, nurse assistants, physicians, pharmacists, performance improvement specialists, and administration. Second, continuation of the maintenance peer audits outside the initial project year has provided an important framework for this project, giving regular opportunities for frontline staff to evaluate patients’ catheter condition and to give feedback to colleagues or “just in time education.” These activities potentially prevent infections in real time. Third, with the many competing priorities demanding clinicians’ attention, it has been important for the CAUTI workgroup to continue to evaluate the problem, to determine where opportunities for improvement remain, and to tailor initiatives to meet those needs. In this way, new work can focus on priorities identified by staff, and CAUTI prevention initiatives remain relevant.
Background: Most medical and surgical devices used in healthcare facilities are made of materials that are sterilized by heat (ie, heat stable), primarily steam sterilization. Low-temperature sterilization methods developed for heat and moisture sensitive devices include ethylene oxide gas (ETO), hydrogen peroxide gas plasma (HPGP), vaporized hydrogen peroxide (VHP), and hydrogen peroxide plus ozone. This study is the first to evaluate the microbicidal activity of the FDA-cleared VHP sterilizer and other methods (Table 1) in the presence of salt and serum (10% FCS). Methods: Brushed stainless steel discs (test carriers) were inoculated with test microbes (Table 1) and subjected to 4 sterilization methods: steam, ETO, VHP and HPGP. Results: Steam sterilization killed all 5 vegetative and 3 spore-forming test organisms in the presence of salt and serum (Table 1). Similarly, the ETO and the HPGP sterilizers inactivated the test organisms with a failure rate of 1.9% for each (ie, 6 of 310 for ETO and 5 of 270 for HPGP). Although steam had no failures compared to both ETO and HPGP, which demonstrated some failures for vegetative bacteria, there was no significant difference comparing the failure rate of steam to either ETO (P > .05) or HPGP (P > .05). However, the VHP system tested failed to inactivate all the test organisms in 76.3% of the tests (206 of 270; P < .00001) (Table 1). Conclusions: This investigation demonstrated that steam sterilization was the most effective method, followed by ETO and HPGP and, lastly, VHP.
Disclosures: Dr. Rutala was a consultant to ASP (Advanced Sterilization Products)
Background: Despite clear guidance for appropriate testing of symptomatic patients for Clostridioides difficile testing (McDonald et al), the ideal testing methodology remains unresolved. Laboratories currently use different algorithms that incorporate enzyme immunoassay (EIA) testing for toxin, glutamate dehydrogenase (GDH) antigen, and polymerase chain reaction (PCR) testing in combination or as a single test. At UNC Hospitals, a large academic hospital with nearly 1,000 beds in the ninth most populous state in the United States, patients are currently tested by an EIA test for toxin and GDH antigen first, and discordant toxin/GDH results are referred for PCR testing. Previous studies have demonstrated that detection of toxin by EIA is a better predictor of C. difficile infection (CDI) complications (Polage et al). Methods: We investigated all patients who were tested for C. difficile from July 2018 to June 2019. Within each testing methodology and result, we assessed the percentage of patients with at least 3 loose stools documented within a 24-hour period, percentage with a severe episode based on white blood cell (WBC) counts >15,000 cells/mL, or percentage with a serum creatinine level >1.5 mg/dL. Fisher-type confidence intervals were calculated for each proportion. Results: Patients positive for C. difficile by the EIA method had 66.9% appropriate loose stool documentation (95% CI, 57.4%–75.5%), whereas patients with EIA-indeterminate (toxin negative, GDH positive) and positive by only PCR had 49.7% appropriate loose stool documentation (95% CI, 42.7%–56.8%). C. difficile patients that tested negative had 48.1% appropriate loose stool documentation (95% CI, 46.0–50.2%). In addition, patients positive by the EIA method had nearly double the proportion of severe disease by WBC or creatinine criteria compared to patients who were either positive by PCR or who tested negative (Table 1). Conclusions: Patients positive for C. difficile by the EIA method were statistically more likely to meet criteria for loose stool documentation. There was no statistically significant difference between patients that tested positive only by PCR or who tested negative. The percentage of patients with severe episode criteria based on WBC or creatinine was nearly doubled between those who tested positive by EIA and PCR (20% vs 10%), although this finding was not statistically significant. The percentage with severe disease (WBC or creatinine) was nearly identical among patients who were positive by PCR and who tested negative. These findings demonstrate that documentation of loose stool is a more sensitive indicator of toxin detection than either clinical parameter, reinforcing the importance of stool documentation in evaluating patients for C. difficile testing.
Background:Candida auris is an emerging fungal pathogen that is often resistant to major classes of antifungal drugs. It is considered a serious global health threat because it has caused severe infections with frequent mortality in over a dozen countries. C. auris can survive on healthcare environmental surfaces for at least 7 days, and it causes outbreaks in healthcare facilities. C. auris has an environmental route of transmission. Thus, infection prevention strategies, such as surface disinfection and room decontamination technologies (eg, ultraviolet [UV-C] light), will be essential to controlling transmission. Unfortunately, data are limited regarding the activity of UV-C to inactivate this pathogen. In this study, a UV-C device was evaluated for its antimicrobial activity against C. auris and C. albicans. Methods: We tested the antifungal activity of a single UV-C device using the vegetative bacteria cycle, which delivers a reflected dose of 12,000 µW/cm2. This testing was performed using Formica sheets (7.6 × 7.6 cm; 3 × 3 inches). The carriers were inoculated with C. auris or C. albicans and placed horizontal on the surface or vertical (ie, perpendicular) to the vertical UV-C lamp and at a distance from 1. 2 m (~4 ft) to 2.4 m (~8 ft). Results: Direct UV-C, with or without FCS (log10 reduction 4.57 and 4.45, respectively), exhibited a higher log10 reduction than indirect UV-C for C. auris (log10 reduction 2.41 and 1.96, respectively), which was statistically significant (Fig. 1 and Table 1). For C. albicans, although direct UV-C had a higher log10 reduction (log10 reduction with and without FCS, 5.26 and 5.07, respectively) compared to indirect exposure (log10 reduction with and without FCS, 3.96 and 3.56, respectively), this difference was not statistically significant. The vertical UV had statistically higher log10 reductions than horizontal UV against C. auris and C. albicans with FCS and without FCS. For example, for C. auris with FCS the log10 reduction for vertical surfaces was 4.92 (95% CI 3.79, 6.04) and for horizontal surfaces the log10 reduction was 2.87 (95% CI, 2.36–3.38). Conclusions:C. auris can be inactivated on environmental surfaces by UV-C as long as factors that affect inactivation are optimized (eg, exposure time). These data and other published UV-C data should be used in developing cycle parameters that prevent contaminated surfaces from being a source of acquisition by staff or patients of this globally emerging pathogen.
Background: Carbapenem-resistant Enterobacteriaceae (CRE) are increasingly common in the United States and have the potential to spread widely across healthcare networks. Only a fraction of patients with CRE carriage (ie, infection or colonization) are identified by clinical cultures. Interventions to reduce CRE transmission can be explored with agent-based models (ABMs) comprised of unique agents (eg, patients) represented by a synthetic population or model-generated representation of the population. We used electronic health record data to determine CRE carriage risk, and we discuss how these results can inform CRE transmission parameters for hospitalized agents in a regional healthcare network ABM. Methods: We reviewed the laboratory data of patients admitted during July 1, 2016−June 30, 2017, to any of 7 short-term acute-care hospitals of a regional healthcare network in North Carolina (N = 118,022 admissions) to find clinically detected cases of CRE carriage. A case was defined as the first occurrence of Enterobacter spp, Escherichia coli, or Klebsiella spp resistant to any carbapenem isolated from a clinical specimen in an admitted patient. We used Poisson regression to estimate clinically detected CRE carriage risk according to variables common to data from both the electronic health records and the ABM synthetic population, including patient demographics, systemic antibiotic administration, intensive care unit stay, comorbidities, length of stay, and admitting hospital size. Results: We identified 58 (0.05%) cases of CRE carriage among all admissions. Among these cases, 30 (52%) were ≥65 years of age and 37 (64%) were female. During their admission, 47 cases (81%) were administered systemic antibiotics and 18 cases (31%) had an intensive care unit stay. Patients administered systemic antibiotics and those with an intensive care unit stay had CRE carriage risk 6.5 times (95% CI, 3.4–12.5) and 4.9 times (95% CI, 2.8–8.5) higher, respectively, than patients without these exposures (Fig. 1). Patients ≥50 years of age and those with a higher Elixhauser comorbidity index score and with longer length of stay also had increased CRE carriage risk. Conclusions: Among admissions in our dataset, CRE carriage risk was associated with systemic antibiotic exposure, intensive care unit stay, higher Elixhauser comorbidity index score, and longer length of stay. We will use these risk estimates in the ABM to inform agents’ CRE carriage status upon hospital admission and the CRE transmission parameters for short-term acute-care hospitals. We will explore CRE transmission interventions in the parameterized regional healthcare network ABM and assess the impact of CRE carriage underestimation.
Funding: This work was supported by Centers for Disease Control and Prevention (CDC) Cooperative Agreement number U01CK000527. The conclusions, findings, and opinions expressed do not necessarily reflect the official position of CDC.
Background: Antibiotic time outs (ABTOs), formal reassessments of all new antimicrobial regimens by the care team, can optimize antimicrobial regimens, reducing antimicrobial overuse and potentially improving outcomes. Implementation of ABTOs is a substantial challenge. We used quality improvement methods to implement robust, meaningful, team-driven ABTOs in general medicine ward services. Methods: We identified and engaged stakeholders to serve as champions for the quality improvement initiative. On October 1, 2018, 2 internal medicine teaching services (services A and B), began conducting ABTOs on all patients admitted to their services receiving systemic antimicrobials for at least 36 hours. Eligible patients were usually identified by the team pharmacist. ABTOs were completed within 72 hours of antibiotic initiation and were documented in the electronic medical record (EMR) by providers using a template. The process was modified as necessary in response to feedback from frontline clinicians using plan-do-study-act (PDSA) methods. We subsequently spread the project to 2 additional internal medicine services (services C and D); 2 family medicine teams (services E and F); and 1 general pediatric service (service G). The project is ongoing. We collected data for the following metrics: (1) proportion of ABTO-eligible patients with an ABTO; (2) proportion of ABTOs conducted within the recommended time frame; (3) documented plan changes as a result of ABTO (eg, change IV antibiotics to PO); (4) proportion of documented plan changes actually completed within 24 hours. Results: Within 12 weeks, services A and B were successfully completing time outs in >80% of their patients. This target was consistently reached by services C, D, E, F, and G almost immediately following launch on those services. As of June 29, 2019, >80% of eligible patients across all participating services have had a time out conducted for 16 consecutive weeks. ABTOs have resulted in a change in management in 35% of cases, including IV-to-PO change in 19% of cases and discontinuation in 5%. Overall, 77% of time outs occurred during the 36–72-hour window. Ultimately, 95% of documented plan changes were completed within 24 hours. Conclusions: ABTOs are effective but implementation is challenging. We achieved high compliance with ABTOs without using electronic reminders. Our results suggest that ABTOs were impactful in the non–critical-care general medicine setting. Next steps include (1) development of EMR-based tools to facilitate identifying eligible patients and ABTO documentation; (2) continued spread through our health care system; and (3) analysis of ABTO impact using ABTO-unexposed patients as a control group.
The algicolous and lichenicolous species Psammina filamentosa is described from the Netherlands and the UK, and is characterized by long (generally over 50 μm) and somewhat tapered conidial arms. Psammina filamentosa is compared with other Psammina specimens found in the same habitat, growing on algae or lichens on the dry side of trees and stones. Psammina filamentosa, P. inflata and P. stipitata differ in the dimensions of their conidial arms. Psammina simplex, however, may be a synonym of P. stipitata, and a DNA study is needed to determine whether it is a distinct species or developing material of P. stipitata. Psammina inflata is also reported as new for the Netherlands. A new worldwide key to the 10 species of Psammina currently known is provided, including three species described from plant material.
To compare the microbicidal activity of low-temperature sterilization technologies (vaporized hydrogen peroxide [VHP], ethylene oxide [ETO], and hydrogen peroxide gas plasma [HPGP]) to steam sterilization in the presence of salt and serum to simulate inadequate precleaning.
Test carriers were inoculated with Pseudomonas aeruginosa, Escherichia coli, Staphylococcus aureus, vancomycin-resistant Enterococcus, Mycobacterium terrae, Bacillus atrophaeus spores, Geobacillus stearothermophilus spores, or Clostridiodes difficile spores in the presence of salt and serum and then subjected to 4 sterilization technologies: steam, ETO, VHP and HPGP.
Steam, ETO, and HPGP sterilization techniques were capable of inactivating the test organisms on stainless steel carriers with a failure rate of 0% (0 of 220), 1.9% (6 of 310), and 1.9% (5 of 270), respectively. The failure rate for VHP was 76.3% (206 of 270).
Steam sterilization is the most effective and had the largest margin of safety, followed by ETO and HPGP, but VHP showed much less efficacy.
A numerical model, based on the two-phase incompressible Navier–Stokes equations, is used to study transmission of regular water waves by a thin floating plate in two dimensions. The model is shown to capture the phenomenon of waves overwashing the plate, and the generation of turbulent bores on the upper plate surface. It is validated against laboratory experimental measurements, in terms of the transmitted wave field and overwash depths, for a set of incident wave periods and steepness values. Corresponding simulations are performed for a thick plate that does not experience overwash, which are validated using experiments where an edge barrier prevents thin-plate overwash. The model accurately reproduces (i) the linear relationship between the transmitted and incident amplitudes for the thick plate, and (ii) the decrease in proportion of incident-wave transmission for the thin plate, as incident steepness increases. Model outputs are used to link the decreasing transmission to wave-energy dissipation in the overwash, particularly where bores collide, and in the surrounding water, particularly at the plate ends. It is shown that most energy dissipation occurs in the overwash for the shortest incident waves tested, and in the surrounding water for the longer incident waves. Further, evidence is given that overwash suppresses plate motions, and causes asymmetry in plate rotations.