The effect of pandemic-related stress on the decision-making process for individual outdoor leisure activities

This study investigates the decision-making process for outdoor leisure activities of the Chinese people in the context of COVID-19. An online survey of residents of Heilongjiang Province was conducted in September and October 2020. In total, 441 questionnaires were returned for empirical analysis. The results reveal that fears of contamination and compulsory checking/reassurance-seeking have had a significant impact on the respondents' goal-directed behavior for nature-based outdoor leisure activities during the pandemic. The theoretical contribution is that extended goal-directed behavior expands with the inclusion of emotional variables and can be used to predict individual outdoor activity intention and decision-making process in the COVID-19 situation relating to leisure. This study provides useful insights for public health ministries and local governments in any country to encourage nature-based outdoor leisure activities as a public health policy for the mental health of the people.

Current status of telemedicine in Japan: implications for Korea. TT -:.

Background: Since the coronavirus disease 2019 outbreak, telemedicine has become an important means of providing medical care worldwide. This study aims to highlight the implications of establishing telemedicine policies in Korea. Japan's telemedicine policies were reviewed from the time of the first trial to the present official allowance. Current Concepts: Since telemedicine demonstration work began in 1971, telemedicine in Japan has advanced in four stages. The first stage was the operation of a remote regional comprehensive medical information system from 1971 to 1997. The second stage was when telemedicine was officially institutionalized from 1997 to 2018. The third stage was the time of expansion of telemedicine, from the announcement of the "Guidelines for the Implementation of Proper Online Care" in 2018 to when online first-time examinations were temporarily allowed in 2020. The fourth stage began in 2021 when the "Permanent Establishment of Special Cases for Online Care" was announced, and telemedicine has been officially allowed to supplement face-to-face care. Telemedicine usage was estimated to be about 53.65 million in 2021, and the total number of treatments in Japan in 2021 was estimated to be about 1.32 billion, accounting for about 4.1% of medical care. Discussion and Conclusion(s): For the Korean government to establish telemedicine, it needs to be promoted step by step through discussions with the medical community. Also, an appropriate medical remuneration system needs to be prepared along with guidelines reflecting the opinions of the medical community to secure the safety of telemedicine.Copyright © Korean Medical Association.

Current status of telemedicine in Japan: implications for Korea

Background: Since the coronavirus disease 2019 outbreak, telemedicine has become an important means of providing medical care worldwide. This study aims to highlight the implications of establishing telemedicine policies in Korea. Japan's telemedicine policies were reviewed from the time of the first trial to the present official allowance. Current Concepts: Since telemedicine demonstration work began in 1971, telemedicine in Japan has advanced in four stages. The first stage was the operation of a remote regional comprehensive medical information system from 1971 to 1997. The second stage was when telemedicine was officially institutionalized from 1997 to 2018. The third stage was the time of expansion of telemedicine, from the announcement of the "Guidelines for the Implementation of Proper Online Care" in 2018 to when online first-time examinations were temporarily allowed in 2020. The fourth stage began in 2021 when the "Permanent Establishment of Special Cases for Online Care" was announced, and telemedicine has been officially allowed to supplement face-to-face care. Telemedicine usage was estimated to be about 53.65 million in 2021, and the total number of treatments in Japan in 2021 was estimated to be about 1.32 billion, accounting for about 4.1% of medical care. Discussion and Conclusion: For the Korean government to establish telemedicine, it needs to be promoted step by step through discussions with the medical community. Also, an appropriate medical remuneration system needs to be prepared along with guidelines reflecting the opinions of the medical community to secure the safety of telemedicine.

COVID-19-associated Pulmonary Aspergillosis: A New Entity

In March 2020, the World Health Organization declared the COVID-19 outbreak a pandemic. This resulted in the discovery of a new clinical Aspergillus disease phenotype, COVID-19-associated pulmonary aspergillosis. This review aimed to collect and share clinical experiences from this new disease. Copyright © 2021 by The Korean Society for Medical Mycology. All right reserved.

Comparison of Supervised Learning Models for COVID-19 Confirmed Cases Prediction using Correlation Analysis

The COVID-19 virus, which first appeared in 2019, has a strong contagious power and is highly spread by people's mobility. In this study, correlation analysis is used in statistical preprocessing of dataset which further used to predict the COVID-19 confirmed cases for next day. Data is divided into two sets by organizing the data set by data preprocessing using correlation analysis. The first dataset is Google Mobility Data of COVID-19 infection with six variables. The second dataset is Google Mobility Data of COVID-19 infection with two variables: (1) Retail stores and leisure facilities (2) Grocery stores and pharmacies. The results of predicting the number of confirmed cases are compared using four supervised machine learning models. Furthermore, the soft voting method is used to show more improved results than the individual performances of each method. © 2022 IEEE.

The effect of digital literacy in the elderly on life satisfaction: Focusing on depression and social participation

Purpose Modern society is facing many changes due to the Fourth Industrial Revolution. In addition, as daily life became non-face-to-face due to the prolonged COVID-19, the use of non-face-to-face digital devices using information and communication technology was further accelerated. Due to these changes, various digital services such as telemedicine and mobile financial services could be used, and functions such as work and school could be maintained even in the COVID-19 situation. However, the rapid transition to an information society further revealed the information vulnerability of the elderly. This is because digital literacy, which is a key competency to adapt in the information society, has acted as a limitation for the elderly, who are vulnerable to information, and their ability to use digital devices. Many previous studies pointed out the low level of informatization in the elderly and various problems that may arise from this(H. S. Kim, J. S. Shim, 2019;NIA, 2020;S. Y. Lee, 2021). The elderly, who are digital vulnerable, are feared to intensify social isolation in the current network era, which is likely to have a negative impact on mental health (Park et al., 2022). Social participation is a representative factor that can control mental health(Kim et al., 2019). Social participation has been verified as a factor that can improve life satisfaction, such as self-realization and overcoming alienation. Therefore, this study attempts to verify the moderated mediating effect of social participation through depression in the relationship between digital literacy and life satisfaction of the elderly. Method This study analyzed 8,664 elderly aged 65 or older who responded to the 2020 Senior Survey conducted jointly with the Korea Institute for Health and Social Affairs and the Ministry of Health and Welfare, and attempted to verify the moderated mediating effect using SPSS 23.0 and SPSS PROCESS 3.4.1. The verification of the research model proceeds in a total of three steps. First, the mediating effect of depression in the relationship between digital literacy and life satisfaction of the elderly is verified using the bootstrapping method. Second, in order to examine the moderating effect of social participation in the relationship between depression and life satisfaction, multiple regression analysis is conducted after averaging. Finally, in the relationship between digital literacy and life satisfaction, the moderated mediating effect of depression is verified by social participation. Results and Discussion The main findings are as follows. First, it was verified that depression had a partial mediating effect in the relationship between digital literacy and life satisfaction. Second, it was verified that social participation had a moderating effect in the relationship between depression and life satisfaction. Third, it was verified that in the relationship between digital literacy and life satisfaction, the mediating effect of depression decreases as social participation increases. This study is meaningful in that it confirmed the effectiveness of digital literacy and social participation as a way to increase life satisfaction of the elderly. Therefore, it is necessary to prepare an informatization education plan to improve the level of digital device use of the elderly, and to provide opportunities to continuously participate in society. These research results will be the basis for suggesting ways to solve problems such as digital information gap and digital inequality for the elderly by establishing welfare for the elderly, education for the elderly, and policies to improve self-efficacy. © 2022, Gerontechnology. All Rights Reserved.

Association of COVID-19 vaccine attitudes and cognitions of COVID-19-related stigma with vaccine hesitancy among college students

This study aimed to examine the association of COVID-19 vaccine attitudes and cognitions of COVID-19-related stigma with vaccine hesitancy among college students. Methods: This cross-sectional study using a web-based survey was conducted with 242 college students in April 2021 before Korea’s national COVID-19 vaccination program had begun. Data were analyzed using multinominal logistic regression analyses. Results: Of the participants who were unsure of their intention to receive the COVID-19 vaccine, 66.0% had less experience with flu vaccinations and were 1.43 times more likely to report a mistrust of vaccine benefits (OR=1.43, CI=1.22, 1.68). Those with no intention of receiving the vaccine were 25.0% less likely to be aware of COVID-19 stigma (OR=0.75, CI=0.65, 0.86), 2.08 times more likely to mistrust vaccine benefits (OR=2.08, CI=1.62, 2.68), and 1.53 times more likely to worry about an unforeseen future negative side effects from vaccination (OR=1.53. CI=1.16, 2.00). Conclusion: Nurses could play an important role in educating college students about vaccination benefits, including reviewing vaccines’ side effects with evidence, to reduce vaccine hesitancy. College students who have less empathy for others regarding COVID-19 infection might have higher COVID-19 vaccine hesitancy. Accordingly, explaining to students the necessity of their vaccination in preventing transmission to the surrounding community and vulnerable populations is critical. © 2022 Korean Academic Society of Nursing Education.

Participation in physical activity among people with disabilities during the COVID-19 pandemic in South Korea

Background: Quarantine, social distancing, and restricted movement and social interaction due to the eoronavinis disease (COVID-19) have been reported reduce physical activity across several countries. However, few studies have evaluated the changes in physical activity patterns before and after COVID-19 among people with disabilities. Therefore, this study aimed to evaluate how physical activity participation has changed during COVID-19 among people with disabilities in South Korea. Methods: This study was conducted among 3871 persons with disabilities, aged 10-69 years, who participated in the 2020 Sports Survey for the Disabled conducted by the Korean Ministry of Culture, Sports and Tourism in March 2020. This survey collected data regarding participants' demographic characteristics (age, gender, etc.) and disability along with the type of physical activity (intensity, frequency, time, etc.), method (facilities, home training, classes/lectures, club), and type (swimming, resistance training, walking and jogging, etc.) of participation in physical activity before and after COVID-19. A chi-squared frequency test was performed to confirm the difference in the ratio of participation frequency, time, intensity, and method and type of physical activity before and after COVID-19. Results: After the COVID-19 outbreak, the frequency, duration, and intensity of physical activity of people with disabilities were reduced compared to before the COVID-19 pandemic. Additionally, in terms of physical activity participation method, attendance of classes, lectures, and clubs decreased, while physical activity at home increased. In participation types of physical activity, participation in walking and jogging, gymnastics, mountain climbing, and cycling increased, whereas swimming, weight training, and other activities decreased. Conclusion: Public health guidelines and social distancing due to COVID-19 have reduced the frequency, duration, and intensity of physical activity, while changing the types and methods of participation in physical activity for people with disabilities. Therefore, public health support to promote adherence to physical activity should be needed.

Gastrointestinal Manifestations in Hospitalized Children With Acute SARS-CoV-2 Infection and Multisystem Inflammatory Condition: An Analysis of the VIRUS COVID-19 Registry

BACKGROUND: Describe the incidence and associated outcomes of gastrointestinal (GI) manifestations of acute coronavirus disease 2019 (COVID-19) and multisystem inflammatory syndrome in hospitalized children (MIS-C). METHODS: Retrospective review of the Viral Infection and Respiratory Illness Universal Study registry, a prospective observational, multicenter international cohort study of hospitalized children with acute COVID-19 or MIS-C from March 2020 to November 2020. The primary outcome measure was critical COVID-19 illness. Multivariable models were performed to assess for associations of GI involvement with the primary composite outcome in the entire cohort and a subpopulation of patients with MIS-C. Secondary outcomes included prolonged hospital length of stay defined as being >75th percentile and mortality. RESULTS: Of the 789 patients, GI involvement was present in 500 (63.3%). Critical illness occurred in 392 (49.6%), and 18 (2.3%) died. Those with GI involvement were older (median age of 8 yr), and 18.2% had an underlying GI comorbidity. GI symptoms and liver derangements were more common among patients with MIS-C. In the adjusted multivariable models, acute COVID-19 was no associated with the primary or secondary outcomes. Similarly, despite the preponderance of GI involvement in patients with MIS-C, it was also not associated with the primary or secondary outcomes. CONCLUSIONS: GI involvement is common in hospitalized children with acute COVID-19 and MIS-C. GI involvement is not associated with critical illness, hospital length of stay or mortality in acute COVID-19 or MIS-C.

Clinical characteristics and treatments of multi-system inflammatory syndrome in children: a systematic review.

OBJECTIVE: Multisystem inflammatory syndrome in children (MIS-C) can occur in association with coronavirus disease 2019 (COVID-19). It is not easy to differentiate MIS-C from severe COVID-19 or Kawasaki disease based on symptoms. The aim of this study was to describe the clinical and laboratory characteristics of MIS-C. PATIENTS AND METHODS: We searched PubMed/Medline for case series and reports of MIS-C published until June 20, 2020. From a total of nine articles involving 45 cases, various clinical and laboratory data were extracted. Each target case was evaluated by using different diagnostic criteria. RESULTS: The average age at onset of MIS-C was 8.6 years. In 80% of cases, the age of patients ranged from 5 to 15 years. Fever (100%) and shock (82%) were the most common presenting symptoms. Sixty percent of cases met the diagnostic criteria for typical or atypical Kawasaki disease. Biomarkers indicative of inflammation, coagulopathy, or cardiac injury were characteristically elevated as follows: ferritin (mean: 1,061 ng/mL), CRP (217 mg/L), ESR (69 mm/hr), IL-6 (214.8 pg/mL), TNFα (63.4 pg/mL), D-dimer (3,220 ng/mL), PT (15.5 s), troponin I (1,006 ng/L), and BNP (12,150 pg/mL). Intravenous immunoglobulin was administered in all target cases, and inotropic agents were commonly used as well. No case of death was observed. CONCLUSIONS: This study demonstrated that MIS-C is a serious condition that presents with fever, rash, as well as cardiovascular and gastrointestinal symptoms. Although it is challenging to differentiate MIS-C from Kawasaki disease or severe COVID-19, initiation of appropriate treatments through early diagnosis is warranted.

Cancer control in Latin America and the Caribbean: recent advances and opportunities to move forward

The increasing burden of cancer represents a substantial problem for Latin America and the Caribbean. Two Lancet Oncology Commissions in 2013 and 2015 highlighted potential interventions that could advance cancer care in the region by overcoming existing challenges. Areas requiring improvement included insufficient investment in cancer control, non-universal health coverage, fragmented health systems, inequitable concentration of cancer services, inadequate registries, delays in diagnosis or treatment initiation, and insufficient palliative services. Progress has been made in key areas but remains uneven across the region. An unforeseen challenge, the COVID-19 pandemic, strained all resources, and its negative effect on cancer control is expected to continue for years. In this Series paper, we summarise progress in several aspects of cancer control since 2015, and identify persistent barriers requiring commitment of additional resources to reduce the cancer burden in Latin America and the Caribbean.

Engineering of Materials for Respiratory Protection: Salt-Coated Antimicrobial Fabrics for Their Application in Respiratory Devices

CONSPECTUS: The development of a highly effective, low-cost method for protection against direct transmission through infectious media associated with respiratory diseases has been considered to be a major challenge in the management of the pandemic outbreak. Currently, filtration in respirators and masks depends on the mesh size, raising safety concerns about direct contact with the virus-laden layers of masks and respirators during use and disposal. Also, conventional medical face masks and respirators are recommended for single use only because long-term use and reuse of masks increase the risk of contact transmission of pathogens. As a result, mask reusability has gained much attention in addressing the global problem of respirator and mask shortages during the COVID-19 pandemic. Furthermore, coinfection by influenza, SARSCoV-2, and bacteria has been an ongoing issue in the current COVID-19 pandemic. In our response to the increasing demand for more convenient forms of disease control, our group has investigated antimicrobial technologies for respiratory devices against pandemic/epidemic diseases and developed two universal antimicrobial coating technologies: (1) nonwashable, reusable salt-coated fabrics and (2) washable, photopolymerizable polymer-coated fabrics which efficiently inactivate infectious viruses by contact with the filter. This is an opportune time to assess research efforts toward antimicrobial face mask technology for its expected impact on society and the economy. In this Account, we introduce the importance of respiratory devices for protection against respiratory diseases, decontamination methods, technical challenges for reuse and extended use, antimicrobial substances used in masks, antimicrobial functionalization strategies for mask fibers, and the characterization of antimicrobial performance and the limitations of the current procedure. Then, the major focus will be directed to discussing the continued efforts of our group to develop antimicrobial fabrics for face mask covers and face masks/respirators based on salt-coated polypropylene (PP) fibers. In the following sections of this Account, we will first discuss salt coating methods and pathogen inactivation mechanisms in salt-coated filters. Then, an overview of our recent progress in evaluating the antimicrobial performance of salt-coated PP fabrics against five different bacterial species, influenza viruses, and human coronaviruses will be presented. The technical challenges in the implementation of the technology will be highlighted in the last section. We believe that easy-to-implement antimicrobial respiratory devices would guarantee improved protection without decontamination processes and enable rapid responses to future pandemic/epidemic outbreaks.

P-137: ITHACA, a randomized multicenter phase 3 study of Isatuximab in combination with Lenalidomide and Dexamethasone in high-risk smoldering Multiple Myeloma: safety run-in preliminary results

Background: High-risk smoldering multiple myeloma (HR-SMM) is associated with a greater risk of progression to symptomatic disease, suggesting the need for early, efficacious therapeutic interventions to improve outcomes. The ongoing, randomized Phase 3 ITHACA study (NCT04270409) is evaluating efficacy and safety of the anti-CD38 monoclonal antibody isatuximab (Isa) in combination with lenalidomide (R) and dexamethasone (d) (Isa-Rd) vs Rd in patients (pts) with HR-SMM. We report here preliminary results from the safety run-in part of this trial. Methods: The primary objective was to confirm the recommended dose of Isa in combination with Rd. Pts were eligible if diagnosed with SMM within 5 years and HR-SMM defined by the Mayo ‘20-2-20’ and/or updated PETHEMA model criteria. Minimal residual disease and imaging by MRI and low-dose whole-body CT/PET-CT will be assessed at fixed time points. Results: As of April 12, 2021, 23 pts (median age, 63 [28–85] years;median time from initial diagnosis, 1.14 [0.1–5.2] years) had received Isa 10 mg/kg once weekly then biweekly (QW-Q2W) in combination with Rd. The median number of cycles was 7 (range, 4–10) and median duration of treatment exposure was 29.7 (range, 16.0–38.0) weeks. Two pts met the Mayo clinical model criteria, 13 pts the PETHEMA model criteria, and 8 pts both models’ criteria for HR-SMM. No pt presented with focal lesions at baseline. Seven (30.4%) pts developed 8 grade ≥3 non-hematologic treatment-emergent adverse events (TEAEs): COVID-19 pneumonia, insomnia (2 each), papular rash, muscle spasm, retinal detachment and hyperglycemia (1 each);no pt experienced a grade 5 TEAE and no pt discontinued treatment due to a TEAE. Serious TEAEs were COVID-19 pneumonia (n=2, grade ≥3) and pneumonia, musculoskeletal chest pain and pyrexia (n=1 each, grade <3). The most common, mostly grade 1–2 TEAEs were insomnia (39%) and constipation, headache, and peripheral edema (22% each). Infusion reactions were reported in 2 pts (8.7%) (grade 2, infusion day 1/cycle 1). By laboratory results, no grade 3–4 anemia or thrombocytopenia was observed;grade 3 neutropenia was reported in 5 pts (21.7%), with no grade 4. Isa exposure and CD38 receptor occupancy were in accordance with other MM studies, reaching target saturation in bone marrow plasma cells. The overall response rate was 86.9%;21.7%, 17.4%, and 4.3% of pts have so far achieved very good partial response (VGPR), complete response (CR) and stringent CR (sCR), respectively. Conclusions: Addition of Isa 10 mg/kg QW-Q2W to Rd was associated with a favorable safety profile in pts with HR-SMM, which compares well with Rd literature data in the same patient population. Isa-Rd has shown encouraging preliminary efficacy (21.7% sCR/CR and 43.4% ≥VGPR rates) in pts with HR-SMM. These results confirm the recommended dose of Isa for the randomized part of the Phase 3 ITHACA study, which will further evaluate efficacy and safety of Isa-Rd in HR-SMM. Funding: Sanofi.

Electrospun Polystyrene and Acid-Treated Cellulose Nanocrystals with Intense Pulsed Light Treatment for N95-Equivalent Filters

The coronavirus (SARS-CoV-2) has prompted a global need and shortage of face masks and respirators. Electrospinning of polystyrene and cellulose nanocrystals (CNCs) is used to fabricate filter materials exceeding N95 standards set by the National Institute for Occupational Health and Safety. The desired filtration efficiency and pressure drop are achieved from filters with varying amounts of input material. The water contact angle, fiber morphology, and surface potential are reported to explain the enhancements in filtration performance after the addition of CNCs or application of intense pulsed light (IPL). The improved durability in the form of increased mechanical properties and lower pressure drop after testing are also examined. The samples exhibited filtration efficiencies greater than 99% and an initial pressure drop as low as 231 Pa. The combination of CNCs and IPL shows the potential to use thinner membranes with less material to achieve comparable filtration performance, which may result in lower manufacturing costs. © 2021 American Chemical Society.

Non-Woven Textiles Formed from Contact Drawn Poly(ethylene oxide) Fibers Provide Tunable Filtration and Virucidal Properties via Entrapment of Silver Nanoparticles

Filtering facepiece respirators (FFRs) protect wearers from inhalation of fine particulates and help prevent transmission of airborne viruses. Here, an FFR material is produced by successive deposition of contact drawn poly(ethylene oxide) (PEO) fibers. Fibers are formed by immersing an array of pins in a highly viscous precursor solution of PEO and then rapidly removing the pins such that polymer entanglement occurs, forming multiple liquid bridges that rapidly dry as they extend. Tunable filtration is achieved by varying the number of PEO fiber elongation cycles. Placing the PEO textiles between two woven cotton cloths provides structural support and additional filtration capacity, achieving a maximum filtration efficiency of 95% with a corresponding initial pressure drop of 281 Pa. The entrapment of silver nanoparticles in the PEO fibers imparts virucidal properties to PEO-based textiles, as demonstrated by inactivation of a human coronavirus HCoV-OC43 and influenza A virus inoculum. The ability to tune filtration efficiency to application needs and provide advanced function through entrapment of active materials represents a versatile tool for limiting exposure to airborne particulates and pathogens.

Effect of Non-face-to-face Voice Therapy Using the Self-Voice Health Care Program for Vocal fatigue

Objectives: Covid-19 has increased the need for non-face-to-face treatment. In particular, professional voice users have a high risk of voice disease due to continuous voice use. The purpose of this study was to investigate the effect of the Self-Voice Health Care Program (SVHCP) which was developed on the basis of Korean speech-language pathologist's vocal behaviors, status and vocal fatigue. Methods: Fifteen speech-language pathologists (2 males and 13 females, the average age was 31.19 years) with voice problems who have more than 25 sessions per week participated via an experimental recruitment SMS and posting from the online speech-language pathologists internet community. Participants watched a 5-minute SVHCP video with instructions and carried out SVHCP daily for one week. The voice measures were carried out before and after SVHCP. Results: K-VHI-10 (p = .017), K-VFI-fatigue (p = .004), K-VFI-physical (p = .019), K-VFI-rest (p = .003), K-VFI-total (p = .005) and total subjective vocal symptoms (p = .009) were significantly lower than before. Additionally, among the subjective vocal symptoms, hypertension when speaking (p = .007), roughness when speaking (p = .007), pain when speaking (p = .034), difficulty with high pitch when singing (p = .017), feelings of voice fatigue (p = .017) were significantly lower than before. Conclusion: Our outcomes demonstrated that the SVHCP was effective in reducing vocal fatigue and subjective vocal symptoms. The SVHCP can help improve voice-related quality of life and voice health for professional voice users. Further research is needed in conjunction with the IT field for the utilization of the SVHCP.

Vaccination Prioritization Strategies for COVID-19 in Korea: A Mathematical Modeling Approach

Coronavirus disease 2019 (COVID-19) vaccination has recently started worldwide. As the vaccine supply will be limited for a considerable period of time in many countries, it is important to devise the effective vaccination strategies that reduce the number of deaths and incidence of infection. One of the characteristics of COVID-19 is that the symptom, severity, and mortality of the disease differ by age. Thus, when the vaccination supply is limited, age-dependent vaccination priority strategy should be implemented to minimize the incidences and mortalities. In this study, we developed an age-structured model for describing the transmission dynamics of COVID-19, including vaccination. Using the model and actual epidemiological data in Korea, we estimated the infection probability for each age group under different levels of social distancing implemented in Korea and investigated the effective age-dependent vaccination strategies to reduce the confirmed cases and fatalities of COVID-19. We found that, in a lower level of social distancing, vaccination priority for the age groups with the highest transmission rates will reduce the incidence mostly, but, in higher levels of social distancing, prioritizing vaccination for the elderly age group reduces the infection incidences more effectively. To reduce mortalities, vaccination priority for the elderly age group is the best strategy in all scenarios of levels of social distancing. Furthermore, we investigated the effect of vaccine supply and efficacy on the reduction in incidence and mortality.

Risk factors of COVID-19 mortality: a systematic review of current literature and lessons from recent retracted articles.

OBJECTIVE: Recently, two influential articles that reported the association of (hydroxy)chloroquine or angiotensin converting enzyme (ACE) inhibitors and coronavirus disease 2019 (COVID-19) mortality were retracted due to significant methodological issues. Therefore, we aimed to analyze the same clinical issues through an improved research method and to find out the differences from the retracted papers. We systematically reviewed pre-existing literature, and compared the results with those of the retracted papers to gain a novel insight. MATERIALS AND METHODS: We extracted common risk factors identified in two retracted papers, and conducted relevant publication search until June 26, 2020 in PubMed. Then, we analyzed the risk factors for COVID-19 mortality and compared them to those of the retracted papers. RESULTS: Our systematic review demonstrated that most demographic and clinical risk factors for COVID-19 mortality were similar to those of the retracted papers. However, while the retracted paper indicated that both (hydroxy)chloroquine monotherapy and combination therapy with macrolide were associated with higher risk of mortality, our study showed that only combination therapy of hydroxychloroquine and macrolide was associated with higher risk of mortality (odds ratio 2.33; 95% confidence interval 1.63-3.34). In addition, our study demonstrated that use of ACE inhibitors or angiotensin receptor blockers (ARBs) was associated with reduced risk of mortality (0.77; 0.65-0.91). CONCLUSIONS: When analyzing the same clinical issues with the two retracted papers through a systematic review of randomized controlled trials and relevant cohort studies, we found out that (hydroxy)chloroquine monotherapy was not associated with higher risk of mortality, and that the use of ACE inhibitors or ARBs was associated with reduced risk of mortality in COVID-19 patients.

Data-driven mobility models for COVID-19 simulation

Agent-based models (ABM) play a prominent role in guiding critical decision-making and supporting the development of effective policies for better urban resilience and response to the COVID-19 pandemic. However, many ABMs lack realistic representations of human mobility, a key process that leads to physical interaction and subsequent spread of disease. Therefore, we propose the application of Latent Dirichlet Allocation (LDA), a topic modeling technique, to foot-traffic data to develop a realistic model of human mobility in an ABM that simulates the spread of COVID-19. In our novel approach, LDA treats POIs as "words"and agent home census block groups (CBGs) as "documents"to extract "topics"of POIs that frequently appear together in CBG visits. These topics allow us to simulate agent mobility based on the LDA topic distribution of their home CBG. We compare the LDA based mobility model with competitor approaches including a naive mobility model that assumes visits to POIs are random. We find that the naive mobility model is unable to facilitate the spread of COVID-19 at all. Using the LDA informed mobility model, we simulate the spread of COVID-19 and test the effect of changes to the number of topics, various parameters, and public health interventions. By examining the simulated number of cases over time, we find that the number of topics does indeed impact disease spread dynamics, but only in terms of the outbreak's timing. Further analysis of simulation results is needed to better understand the impact of topics on simulated COVID-19 spread. This study contributes to strengthening human mobility representations in ABMs of disease spread. © 2020 ACM.