[Management of COVID-19 pandemic in hospital at home in two regional Spanish hospitals. what it meant, who we cared for, who died and how assistance has evolved over time]. / Manejo de la pandemia de COVID-19 en hospitalización domiciliaria en dos hospitales comarcales españoles: qué significó, quiénes atendimos, quién falleció y como evolucionó la asistencia a lo largo del tiempo.

OBJECTIVE: Home Hospitalization (HH) is an alternative hospitalization modality that can be very useful in times of health stress such as the COVID-19 pandemic. This paper includes the management of patients admitted with COVID-19 in HH in two county spanish hospitals for two years. METHODS: A descriptive, observational and retrospective study of all patients admitted at HH with a diagnosis of COVID-19 disease was carried out. Subsequently, further analysis was carried out to characterize the patients who died in HH or 30 days after discharge and another to compare the management between the first phase of the study (2020) and the second one (2021 and part of 2022). RESULTS: A total of 167 patients were recruited. A 52.1% moved to watch that the recovery continued compared to 40.7% in which it was done to watch that they did not worsen. The patients who died in HAD were older (mean 87.5 years), more comorbid and more likely to have do-not resucitate orders (DNR) in case of cardiac arrest (85%). In the second phase of the study, older patients, more comorbid patients and with a greater degree of DNR orders were admitted than those admitted throughout 2020. CONCLUSIONS: HAD is a useful resource to increase the resilience of health systems in cases of stress such as the disease caused by COVID-19. The development and growth of existing units, as well as the creation of new ones where they do not exist, could be a basic tool for the medicine of the future.

Evaluating dry vs. wet disinfection in boot baths on detection of porcine epidemic diarrhea virus and porcine reproductive and respiratory virus RNA.

Maintaining biosecurity between swine barns is challenging, and boot baths are an easily implementable option some utilize to limit pathogen spread. However, there are concerns regarding their efficacy, especially when comparing wet or dry disinfectants. The objective of this study was to evaluate the efficacy of boot baths in reducing the quantity of detectable porcine epidemic diarrhea virus (PEDV) and porcine reproductive and respiratory syndrome virus (PRRSV) genetic material using wet or dry disinfectants. Treatments included 1) control, 2) dry chlorine powder (Traffic C.O.P., PSP, LLC, Rainsville, AL), and 3) wet quaternary ammonium/glutaraldehyde liquid (1:256 Synergize, Neogen, Lexington, KY). Prior to disinfection, rubber boots were inoculated with 1 mL of a co-inoculants of PRRSV (1 × 105 TCID50 per mL) and PEDV (1 × 105 TCID50 per mL) and dried for 15 min. After the drying period, a researcher placed the boot on the right foot and stepped directly on a stainless steel coupon (control). Alternatively, the researcher stepped first into a boot bath containing either the wet or dry sanitizer, stood for 3 s, and then stepped onto a steel coupon. After one minute, an environmental swab was then collected and processed from each boot and steel coupon. The procedure was replicated 12 times per disinfectant treatment. Samples were analyzed using a duplex qPCR at the Kansas State Veterinary Diagnostic Laboratory. Cycle threshold values were analyzed using SAS GLIMMIX v 9.4 (SAS, Inc., Cary, NC). There was no evidence of a disinfectant × surface × virus interaction (P > 0.10). An interaction between disinfectant × surface impacted (P < 0.05) the quantity of detectable viral RNA. As expected, the quantity of the viruses on the coupon was greatest in the control, indicating that a contaminated boot has the ability to transfer viruses from a contaminated surface to a clean surface. Comparatively, the dry disinfectant treatment resulted in no detectable viral RNA on either the boot or subsequent coupon. The wet disinfectant treatment had statistically similar (P > 0.05) viral contamination to the control on the boot, but less viral contamination compared to the control on the metal coupon. In this experiment, a boot bath with dry powder was the most efficacious in reducing the detectable viral RNA on both boots and subsequent surfaces.

Improving Medical Student Mentorship in Orthopaedic Surgery.

Introduction: Owing to limited clinical clerkships and travel restrictions related to COVID-19, recent medical student mentorship in orthopaedic surgery has been impacted negatively. The purpose of this quality improvement (QI) project was to determine if medical student awareness of orthopaedics as a possible career field may be improved through a mentoring program designed and delivered by orthopaedic residents. Methods: A five-resident QI team developed four educational sessions aimed at a medical student audience. Forum topics included: (1) orthopaedics as a career, (2) fracture conference, (3) splinting workshop, and (4) residency application process. Pre- and post-forum surveys were administered to student participants to assess changes in their perceptions regarding orthopaedic surgery. Data derived from the questionnaires were analyzed with nonparametric statistical tests. Results: Of 18 forum participants, 14 were men and 4 were women. A total of 40 survey pairs were collected, averaging 10 per session. In the all-participant encounter analysis, there were statistically significant improvements in all outcome measures including interest in, exposure to, and knowledge of orthopaedics; exposure to our training program; and ability to interact with our residents. Those undecided regarding their specialty demonstrated larger increases in post-forum responses, suggesting that the learning experience was more impactful for that subgroup. Conclusions: This QI initiative was a successful demonstration of orthopaedic resident mentorship of medical students, wherein perceptions of orthopaedics were influenced favorably by the educational experience. For some students with limited access to orthopaedic clerkships or formal one-on-one mentoring, forums like these may be an acceptable alternative.

Dopamine Dysregulation and Altered Responses to Drugs Affecting Dopaminergic Transmission in a New Dopamine Transporter Knockout (DAT-KO) Rat Model.

Under normal conditions, dopamine (DA) clearance after release largely depends on uptake by the DA transporter (DAT). DAT expression/activity is reduced in some neuropsychiatric and neurological disorders. Our aim was to characterize the behavioral, neurochemical and electrophysiological effects of eliminating DAT in a novel knockout rat model we generated using CRISPR/Cas9. Consistent with existing DAT-KO models, our DAT-KO rats displayed increased locomotion, paradoxical calming by amphetamine, and reduced kinetics of DA clearance after stimulated release. Reduced DA kinetics were demonstrated using fast-scan cyclic voltammetry in brain slices containing the striatum or substantia nigra pars compacta (SNc) and in the dorsal striatum in vivo. Cocaine enhanced DA release in wild-type (WT) but not DAT-KO rats. Basal extracellular DA concentration measured with fast-scan controlled-adsorption voltammetry was higher in DAT-KO rats both in the striatum and SNc and was enhanced by L-DOPA (particularly after pharmacological block of monoamine oxidase), confirming that DA release after L-DOPA is not due to DAT reversal. The baseline firing frequency of SNc neurons was similar in both genotypes. However, D2 receptor-mediated inhibition of firing (by quinpirole or L-DOPA) was blunted in DAT-KO rats, while GABAB-mediated inhibition was preserved. We have also provided new data for the DAT-KO rat regarding the effects of slowing DA diffusion with dextran and blocking organic cation transporter 3 with corticosterone. Together, our results validate our DAT-KO rat and provide new insights into the mechanisms of chronic dysregulation of the DA system by addressing several unresolved issues in previous studies with other DAT-KO models.

Loss-of-function mutation in Omicron variants reduces spike protein expression and attenuates SARS-CoV-2 infection (preprint)

SARS-CoV-2 Omicron variants emerged in 2022 with >30 novel amino acid mutations in the spike protein alone. While most studies focus on the impact of receptor binding domain changes, mutations in the C-terminal of S1 (CTS1), adjacent to the furin cleavage site, have largely been ignored. In this study, we examined three Omicron mutations in CTS1: H655Y, N679K, and P681H. Generating a SARS-CoV-2 triple mutant (YKH), we found that the mutant increased spike processing, consistent with prior reports for H655Y and P681H individually. Next, we generated a single N679K mutant, finding reduced viral replication in vitro and less disease in vivo. Mechanistically, the N679K mutant had reduced spike protein in purified virions compared to wild-type; spike protein decreases were further exacerbated in infected cell lysates. Importantly, exogenous spike expression also revealed that N679K reduced overall spike protein yield independent of infection. Together, the data show that N679K is a loss-of-function mutation reducing overall spike levels during omicron infection, which may have important implications for disease severity, immunity, and vaccine efficacy.

Severe Acute Respiratory Syndrome Coronavirus-2 Lambda Variant Collected from a Child from Arkansas and Sequenced.

An eleven-year-old tested positive for SARS-CoV-2 Lambda variant. Sequencing was performed on the Oxford Nanopore and the Illumina NextSeq 500. Both platforms identified all 7 of the synonymous mutations in the sample, while all 28 nonsynonymous mutations were identified from Oxford Nanopore and 20 nonsynonymous mutations were identified from Illumina.

IMPROVING COMMUNICATION WITH RELATIVES IN THE COVID ERA - DEVELOPMENT OF A NEW SERVICE STANDARD

Background: Quality improvement project undertaken by the Ageing and Complex Medicine team to improve the quality and quantity of communication with patients' relatives. Introduction: Visitation restrictions at RAEI since the onset of the COVID pandemic have created barriers to effective communication between patients' relatives and the medical team. Patients' relatives were frequently receiving poorly structured information, incorrect information, or even no information. This problem was hospital wide and likely to have affected other trusts. It particularly affected elderly care wards, where the cohort of patients were often less able provide their relatives with updates themselves. We therefore agreed a service standard whereby the medical team would provide a medical update via phone to the patients' next of kin within 24 hours of admission followed by twice weekly updates by any member of the wider MDT. Our aim was to improve the quality and quantity of communication with the patients' relatives. Method: So far 6 data capture cycles have seen us implement change in various ways such as utilisation of a white board to highlight when updates are due, a staff feedback survey to highlight barriers to providing the service and a relative feedback survey to evaluate their experience. Results: Compared to baseline data we have seen an improvement in the quantity of relative updates with most cycles. Conclusion: We have improved the quantity of relative updates and embedded it as established culture on Astley ward. Barriers to success include staffing levels, time burden, and low confidence levels amongst junior doctors. Cycle 7 will see implementation of a teaching session for new junior doctor cohorts to improve their confidence. I would like to share our learning and success with the wider hospital and see implementation of the service standard across all wards within the trust.

EVALUATING THE EFFECTS OF SOCIAL DETERMINANTS OF HEALTH ON COVID-19 SEVERITY AT DIAGNOSIS, AND ANXIETY, DEPRESSION AND QUALITY OF LIFE OUTCOMES ≥ 6 MONTHS AFTER DIAGNOSIS

BACKGROUND: COVID-19 continues to be an ongoing problem worldwide, especially for those who are disproportionately affected due to their social determinants of health, as they are often at a socioeconomic disadvantage. We are primarily interested in evaluating how education level, income, race, ethnicity, and obesity are correlated with acute COVID-19 severity, and anxiety, depression, and quality of life ≥ 6 months post-infection. Specifically, obesity (BMI > 30), has been previously identified as a risk factor for COVID- 19 regarding severity and mortality. We found it imperative to further investigate these demographic variables, as they are vital in understanding how social determinants of health are impacting COVID-19 outcomes. Insights from this study can assist with identifying gaps in care for those with poor social determinants of health, as well as help shape care for those who have been disproportionately affected. METHODS: We examined records of COVID-19 patients through the COVID-19 Recovery Clinic at George Washington University in Washington, D.C. that has been collecting data on patient short and long-term COVID-19 outcomes in various domains along with demographic information since November 2020. Using RStudio with calculations of descriptive data, odds ratios, and p-values using Fisher's exact test, we assessed education level, income, race, ethnicity, and obesity and looked at how they correlated with COVID-19 severity at diagnosis, presence of anxiety, depression and quality of life ≥ 6 months after acute infection. RESULTS: From our sample (n=150), we found African Americans had greater acute COVID-19 severity (OR=7.56, 95% CI 2.22, 25.68, p=0.0015) relative to white individuals. We also found that obesity was associated with higher levels of acute COVID-19 severity (OR=4.89, 95% CI 1.36, 17.60, p=0.022).Additionally, during acute COVID-19 infection, 7/32 (21.9%) obese patients compared to 9/112 (8.0%) non-obese patients were hospitalized (OR=3.79, 95%CI=1.23, 11.68, p=0.03).No significant association was found between anxiety, depression, quality of life or COVID- 19 severity and persistent symptoms. CONCLUSIONS: We observed associations between the African American race and more severe acute COVID-19 infection. Further, in the acute phase, we observed that obese patients were more likely than non-obsese patients to have more severe infection and be hospitalized. These findings highlight preexisting gaps in healthcare outcomes regarding social determinants of health. It is essential to analyze many of the potential longer-term effects of COVID-19 infection, as they remain poorly understood. We conclude that larger studies are necessary to better understand the effects of social determinants of health on both short and long-term outcomes of COVID-19.

RISK FACTORS ASSOCIATED WITH THE CLINICAL OUTCOMES OF ACUTE AND POST-ACUTE COVID-19 IN ADULT PATIENTS

BACKGROUND: During the COVID-19 pandemic, most attention has been focused on the acute phase of the disease, but lingering symptoms from the postacute sequelae of COVID-19 (PASC) merit concern. The George Washington University COVID-19 Recovery Clinic is documenting these presentations to better understand PASC and its precipitating factors. The group implemented definitions for six phenotype categories: pulmonary, cardiac, connective tissue, vascular, central nervous system (CNS), and other. This research seeks to identify pre-existing factors that could affect disease severity, understand their effect on PASC symptoms at 6-15 months post-infection, and determine associations between patient history and PASC phenotypes. METHODS: An IRB-approved, retrospective cohort study was performed from charts of adult patients with persistent symptoms after acute COVID-19. Data were ed from clinical history prior to COVID-19 diagnosis, during acute COVID-19, and during the post-acute phase, including laboratory results and responses from mental health assessment tools. PASC phenotypes were determined clinically and hospitalization was used as a proxy for disease severity. Descriptive statistics, unadjusted odds ratios, and significance tests (Fisher's exact test, Chi-square test, and Mann-Whitney U test) were calculated using RStudio (4.1.1). RESULTS: Study participants with persistent symptoms at 6-15 months postinfection (n=116) had a mean age of 45.16 (SD 13.23), of which 70% were female, 60% were Caucasian, 12% were African-American, 9% were Asian, and 3% were Hispanic/Latino. When including all patients who had persistent symptoms at 1-15 months post-infection, those with obesity (BMI ≥30) or type 2 diabetes were much more likely to undergo a severe acute phase of COVID19 (OR 12.75;95% CI 1.91-84.95;p=0.02;n=61 and OR 34.67;95% CI 4.43-271.46;p<0.001;n=61 respectively). At 6-15 months post-infection, those suffering from a pulmonary PASC phenotype were more likely to have smoked (OR 3.27;95% CI 1.18-9.11;p=0.02;n=91). At the same period, those presenting with at least one CNS phenotype had a significantly higher level of C-reactive protein (CRP) than those without a CNS phenotype presentation (Mean 3.70 mg/L, SD 5.19 vs. Mean 1.26 mg/L, SD 2.36;p=0.009;n=53). Additionally, acute phase severity was not significantly associated with the presence of PASC. CONCLUSIONS: Our research further demonstrates the increased risk of severe acute COVID-19 among patients with obesity and type 2 diabetes. Furthermore, we show that those with a smoking history were more likely to continue to have pulmonary symptoms of COVID-19 at 6-15 months postinfection. Additionally, our study suggests that there may be a relationship between CRP and persistent CNS symptoms. A better understanding of these associations can help predict the full burden of COVID-19 and improve clinical guidance.

Effects of reducing the standardized ileal digestible lysine and tryptophan to lysine ratio to slow growth of finishing pigs.

The COVID-19 global pandemic greatly affected pork processing plants in the United States. These pork processing plants were forced to either temporarily close or operate at reduced capacity due to the increased number of health-related employee absences. Because finishing pigs could not be timely marketed, methods to reduce growth performance were required to keep pigs from becoming too heavy at slaughter weight. Therefore, our objective was to determine the extent that reducing dietary standardized ileal digestible (SID) Lys and tryptophan-to-lysine ratio (Trp:Lys) ratio would slow finishing pig average daily gain (ADG) in a commercial setting. A total of 1,080 finishing pigs (327 × 1050, PIC; initially 32.3 kg) were used in a 119-d growth trial. Pigs were allotted by initial body weight (BW) and randomly assigned to 1 of 4 dietary treatments in a completely randomized block design with 27 pigs per pen and 10 pens per treatment. Three dietary regimes were formulated to contain either 100%, 90%, or 80% of the estimated SID Lys requirement for pigs in this facility, with a SID Trp:Lys ratio of 19%, with the exception of the last dietary phase formulated to 17% SID Trp:Lys. Seven different dietary phases were fed. The SID Lys concentrations in the 100% diets were: 1.10%, 1.01%, 0.91%, 0.83%, 0.79%, 0.71%, or 0.67% SID Lys from 32 to 40, 40 to 51, 51 to 72, 72 to 85, 85 to 98, 98 to 112, and 112 to 130 kg, respectively. A fourth regime was formulated to 80% SID Lys with a SID Trp:Lys ratio of 16% (80-16% SID Trp:Lys) throughout all phases. Overall from d 0 to 119, ADG (linear, P < 0.001), final BW (linear, P < 0.001), and gain-to-feed (G:F) decreased (linear, P = 0.087) as SID Lys decreased from 100% to 80% of the estimated requirement. Pigs fed the 80-16% SID Trp:Lys diets had an additional decrease in ADG (P < 0.05) and G:F (P < 0.10) compared with pigs fed 80% of the SID Lys requirement with the normal Trp:Lys ratio. The reduction in SID Lys (from 100% to 80%) and reduction in SID Lys and Trp:Lys ratio resulted in an 8.6 and 11.7 kg, respectively, decrease in final BW compared with pigs fed Lys and Trp at the requirement (100%). This study provides alternatives for pork producers to reduce growth rate of finishing pigs.

Antigenic and virological properties of an H3N2 variant that continues to dominate the 2021-22 Northern Hemisphere influenza season.

Influenza viruses circulated at very low levels during the beginning of the COVID-19 pandemic, and population immunity against these viruses is low. An H3N2 strain (3C.2a1b.2a2) with a hemagglutinin (HA) that has several substitutions relative to the 2021-22 H3N2 vaccine strain is dominating the 2021-22 Northern Hemisphere influenza season. Here, we show that one of these substitutions eliminates a key glycosylation site on HA and alters sialic acid binding. Using glycan array profiling, we show that the 3C.2a1b.2a2 H3 maintains binding to an extended biantennary sialoside and replicates to high titers in human airway cells. We find that antibodies elicited by the 2021-22 Northern Hemisphere influenza vaccine poorly neutralize the 3C.2a1b.2a2 H3N2 strain. Together, these data indicate that 3C.2a1b.2a2 H3N2 viruses efficiently replicate in human cells and escape vaccine-elicited antibodies.

Gain-of-Signal Assays for Probing Inhibition of SARS-CoV-2 Mpro/3CLpro in Living Cells.

The main protease, Mpro, of SARS-CoV-2 is required to cleave the viral polyprotein into precise functional units for virus replication and pathogenesis. Here, we report quantitative reporters for Mpro function in living cells in which protease inhibition by genetic or chemical methods results in robust signal readouts by fluorescence (enhanced green fluorescent protein [eGFP]) or bioluminescence (firefly luciferase). These gain-of-signal systems are scalable to high-throughput platforms for quantitative discrimination between Mpro mutants and/or inhibitor potencies as evidenced by validation of several reported inhibitors. Additional utility is shown by single Mpro amino acid variants and structural information combining to demonstrate that both inhibitor conformational dynamics and amino acid differences are able to influence inhibitor potency. We further show that a recent variant of concern (Omicron) has an unchanged response to a clinically approved drug, nirmatrelvir, whereas proteases from divergent coronavirus species show differential susceptibility. Together, we demonstrate that these gain-of-signal systems serve as robust, facile, and scalable assays for live cell quantification of Mpro inhibition, which will help expedite the development of next-generation antivirals and enable the rapid testing of emerging variants. IMPORTANCE The main protease, Mpro, of SARS-CoV-2 is an essential viral protein required for the earliest steps of infection. It is therefore an attractive target for antiviral drug development. Here, we report the development and implementation of two complementary cell-based systems for quantification of Mpro inhibition by genetic or chemical approaches. The first is fluorescence based (eGFP), and the second is luminescence based (firefly luciferase). Importantly, both systems rely upon gain-of-signal readouts such that stronger inhibitors yield higher fluorescent or luminescent signal. The high versatility and utility of these systems are demonstrated by characterizing Mpro mutants and natural variants, including Omicron, as well as a panel of existing inhibitors. These systems rapidly, safely, and sensitively identify Mpro variants with altered susceptibilities to inhibition, triage-nonspecific, or off-target molecules and validate bona fide inhibitors, with the most potent thus far being the first-in-class drug nirmatrelvir.

Preliminary evidence that brief exposure to vaccination-related internet memes may influence intentions to vaccinate against COVID-19.

Despite global efforts to rapidly distribute COVID-19 vaccines, early estimates suggested that 29-35% of the population were hesitant/unwilling to receive them. Countering such vaccine hesitancy is thus an important priority. Across two sets of online studies (total n = 1584) conducted in the UK before (August-October 2020) and immediately after the first effective vaccine was publicly announced (November 10-19, 2020), brief exposure (<1 min) to vaccination memes boosted the potentially life-saving intention to vaccinate against COVID-19. These intention-boosting effects, however, weakened once a COVID-19 vaccine became a reality (i.e., after the announcement of a safe/effective vaccine), suggesting meme-based persuasion may be context-dependent. These findings thus represent preliminary evidence that naturally circulating memes may-under certain circumstances-influence public intentions to vaccinate, although more research regarding this context-specificity, as well as the potential psychological mechanisms through which memes act, is needed.

Germinal center responses to SARS-CoV-2 mRNA vaccines in healthy and immunocompromised individuals.

Vaccine-mediated immunity often relies on the generation of protective antibodies and memory B cells, which commonly stem from germinal center (GC) reactions. An in-depth comparison of the GC responses elicited by SARS-CoV-2 mRNA vaccines in healthy and immunocompromised individuals has not yet been performed due to the challenge of directly probing human lymph nodes. Herein, through a fine-needle aspiration-based approach, we profiled the immune responses to SARS-CoV-2 mRNA vaccines in lymph nodes of healthy individuals and kidney transplant recipients (KTXs). We found that, unlike healthy subjects, KTXs presented deeply blunted SARS-CoV-2-specific GC B cell responses coupled with severely hindered T follicular helper cell, SARS-CoV-2 receptor binding domain-specific memory B cell, and neutralizing antibody responses. KTXs also displayed reduced SARS-CoV-2-specific CD4 and CD8 T cell frequencies. Broadly, these data indicate impaired GC-derived immunity in immunocompromised individuals and suggest a GC origin for certain humoral and memory B cell responses following mRNA vaccination.

COVID-19 vaccine hesitancy among university students in Lebanon.

Little is known about the decision-making process of college students in Lebanon regarding coronavirus disease-2019 (COVID-19) vaccination. The aim of this study was to identify factors predicting behavioural intentions of students enrolled at the American University of Beirut to obtain a COVID-19 vaccine. A total of 3805 students were randomly selected. Participants were divided into three groups: vaccine accepting (willing to take or already took the vaccine), vaccine hesitant (hesitant to take the vaccine) and vaccine resistant (decided not to take the vaccine). Overall, participants were vaccine accepting (87%), with 10% and 3% being hesitant and resistant, respectively. Vaccine hesitancy was significantly associated with nationality, residency status and university rank. Participants who believed the vaccine was safe and in agreement with their personal views were less likely to be hesitant. Participants who did not receive the flu vaccine were more hesitant than those who did. Moreover, a significant association between hesitancy and agreement with conspiracies was observed. A high level of knowledge about COVID-19 disease and vaccine resulted in lower odds of vaccine resistance among students. The factors identified explaining each of the three vaccine intention groups can be used as core content for health communication and social marketing campaigns to increase the rate of COVID-19 vaccination.

Risk quantification for SARS-CoV-2 infection through airborne transmission in university settings.

The COVID-19 pandemic has significantly impacted learning as many institutions switched to remote or hybrid instruction. An in-depth assessment of the risk of infection that considers environmental setting and mitigation strategies is needed to make safe and informed decisions regarding reopening university spaces. A quantitative model of infection probability that accounts for space-specific parameters is presented to enable assessment of the risk in reopening university spaces at given densities. The model uses the fraction of the campus population that are viral shedders, room capacity, face covering filtration efficiency, air exchange rate, room volume, and time spent in the space as parameters to calculate infection probabilities in teaching spaces, dining halls, dorms, and shared bathrooms. The model readily calculates infection probabilities in various university spaces, with face covering filtration efficiency and air exchange rate being among the dominant variables. When applied to university spaces, this model demonstrated that, under specific conditions that are feasible to implement, in-person classes could be held in large lecture halls with an infection risk over the semester <1%. Meal pick-ups from dining halls and usage of shared bathrooms in residential dormitories among small groups of students could also be accomplished with low risk. The results of applying this model to spaces at Harvard University (Cambridge and Allston campuses) and Stanford University are reported. Finally, a user-friendly web application was developed using this model to calculate infection probability following input of space-specific variables. The successful development of a quantitative model and its implementation through a web application may facilitate accurate assessments of infection risk in university spaces. However, since this model is thus far unvalidated, validation using infection rate and contact tracing data from university campuses will be crucial as such data becomes available at larger scales. In light of the impact of the COVID-19 pandemic on universities, this tool could provide crucial insight to students, faculty, and university officials in making informed decisions.

3D Printed frames to enable reuse and improve the fit of N95 and KN95 respirators.

BACKGROUND: In response to supply shortages caused by the COVID-19 pandemic, N95 filtering facepiece respirators (FFRs or "masks"), which are typically single-use devices in healthcare settings, are routinely being used for prolonged periods and in some cases decontaminated under "reuse" and "extended use" policies. However, the reusability of N95 masks is limited by degradation of fit. Possible substitutes, such as KN95 masks meeting Chinese standards, frequently fail fit testing even when new. The purpose of this study was to develop an inexpensive frame for damaged and poorly fitting masks using readily available materials and 3D printing. RESULTS: An iterative design process yielded a mask frame consisting of two 3D printed side pieces, malleable wire links that users press against their face, and cut lengths of elastic material that go around the head to hold the frame and mask in place. Volunteers (n = 45; average BMI = 25.4), underwent qualitative fit testing with and without mask frames wearing one or more of four different brands of FFRs conforming to US N95 or Chinese KN95 standards. Masks passed qualitative fit testing in the absence of a frame at rates varying from 48 to 94 % (depending on mask model). For individuals who underwent testing using respirators with broken or defective straps, 80-100 % (average 85 %) passed fit testing with mask frames. Among individuals who failed fit testing with a KN95, ~ 50 % passed testing by using a frame. CONCLUSIONS: Our study suggests that mask frames can prolong the lifespan of N95 and KN95 masks by serving as a substitute for broken or defective bands without adversely affecting fit. Use of frames made it possible for ~ 73 % of the test population to achieve a good fit based on qualitative and quantitative testing criteria, approaching the 85-90 % success rate observed for intact N95 masks. Frames therefore represent a simple and inexpensive way of expanding access to PPE and extending their useful life. For clinicians and institutions interested in mask frames, designs and specifications are provided without restriction for use or modification. To ensure adequate performance in clinical settings, fit testing with user-specific masks and PanFab frames is required.