Investigation on external quantum efficiency droops and inactivation efficiencies of AlGaN-based ultraviolet-c LEDs at 265-285 nm.

The temperature-dependent external quantum efficiency (EQE) droops of 265 nm, 275 nm, 280 nm, and 285 nm AlGaN-based ultraviolet-c light-emitting diodes (UVC-LEDs) differed in Al contents have been comprehensively investigated. The modifiedABCmodel (R = An+Bn2+Cn3) with the current-leakage related term,f(n)= Dn4, has been employed to analyze the recombination mechanisms in these UVC-LED samples. Experimental results reveal that, at relatively low electrical-current levels, the contribution of Shockley-Read-Hall (SRH) recombination exceeds those of the Auger recombination and carrier leakage. At relatively high electrical-current levels, the Auger recombination and carrier leakage jointly dominate the EQE droop phenomenon. Moreover, the inactivation efficiencies of 222 nm excimer lamp, 254 nm portable Mercury lamp, 265 nm, 280 nm, and 285 nm UVC-LED arrays in the inactivation ofEscherichia colihave been experimentally investigated, which could provide a technical reference for fighting against the new COVID-19.

Safety, Efficacy, and Immunogenicity of Varying Types of COVID-19 Vaccines in Children Younger Than 18 Years: An Update of Systematic Review and Meta-Analysis.

Vaccination is one of the most effective measures for children as the epidemic progresses. However, there is a significant research gap in the meta-analysis of the COVID-19 vaccines for children younger than 18 years. This study is a comprehensive review of different COVID-19 vaccines. Published articles were retrieved from PubMed, Embase, and the Cochrane Library. Twelve randomized controlled trials (RCTs) of COVID-19 vaccines were included in the review until 21 October 2022. Most local and systemic adverse reactions were predominantly mild to moderate in severity and disappeared quickly after different types of vaccines. The subunit vaccine had the highest safety. The significant risk was lower in the subunit vaccine group after the initial (RR 1.66, 95% CI 1.26-2.17, p = 0.0003) and booster vaccination (RR 1.40, 95% CI 1.02-1.92, p = 0.04). Younger children had a more outstanding safety profile in the mRNA and inactivated vaccine groups. The humoral immune response was proportional to the number of doses in the inactivated and the adenovirus vaccine groups, and the strength of immunogenicity was negatively correlated with age in the inactivated vaccine. The mRNA and the subunit vaccines provided satisfactory prevention against COVID-19, especially seven days after the booster dose. However, more research and longer-term follow-up are needed to assess the duration of immune responses, efficacy, and safety.

Guidelines for the prevention and management of children and adolescents with COVID-19.

Children are the future of the world, but their health and future are facing great uncertainty because of the coronavirus disease 2019 (COVID-19) pandemic. In order to improve the management of children with COVID-19, an international, multidisciplinary panel of experts developed a rapid advice guideline at the beginning of the outbreak of COVID-19 in 2020. After publishing the first version of the rapid advice guideline, the panel has updated the guideline by including additional stakeholders in the panel and a comprehensive search of the latest evidence. All recommendations were supported by systematic reviews and graded using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) system. Expert judgment was used to develop good practice statements supplementary to the graded evidence-based recommendations. The updated guideline comprises nine recommendations and one good practice statement. It focuses on the key recommendations pertinent to the following issues: identification of prognostic factors for death or pediatric intensive care unit admission; the use of remdesivir, systemic glucocorticoids and antipyretics, intravenous immunoglobulin (IVIG) for multisystem inflammatory syndrome in children, and high-flow oxygen by nasal cannula or non-invasive ventilation for acute hypoxemic respiratory failure; breastfeeding; vaccination; and the management of pediatric mental health. CONCLUSION: This updated evidence-based guideline intends to provide clinicians, pediatricians, patients and other stakeholders with evidence-based recommendations for the prevention and management of COVID-19 in children and adolescents. Larger studies with longer follow-up to determine the effectiveness and safety of systemic glucocorticoids, IVIG, noninvasive ventilation, and the vaccines for COVID-19 in children and adolescents are encouraged. WHAT IS KNOWN: • Several clinical practice guidelines for children with COVID-19 have been developed, but only few of them have been recently updated. • We developed an evidence-based guideline at the beginning of the COVID-19 outbreak and have now updated it based on the results of a comprehensive search of the latest evidence. WHAT IS NEW: • The updated guideline provides key recommendations pertinent to the following issues: identification of prognostic factors for death or pediatric intensive care unit admission; the use of remdesivir, systemic glucocorticoids and antipyretics, intravenous immunoglobulin for multisystem inflammatory syndrome in children, and high-flow oxygen by nasal cannula or non-invasive ventilation for acute hypoxemic respiratory failure; breastfeeding; vaccination; and the management of pediatric mental health.

Attitudes and Factors Associated With Intention to the Third Dose of COVID-19 Vaccine Among Adolescents: A Cross-Sectional Survey in 3 Provinces of China.

OBJECTIVE: The COVID-19 caused a world pandemic, posing a huge threat to global health. Widespread vaccination is the most effective way to control the pandemic. Vaccination with the third dose of the COVID-19 vaccine is currently underway. We aimed to determine the attitude of adolescents toward the third dose of COVID-19 vaccine. METHODS: A structured questionnaire was administered between 16 August and 28 October 2021 among adolescents aged 12-17 years in three provinces of eastern region of China based on convenience sampling. The questionnaire was specifically developed to assess the adolescents' attitude toward and willingness to accept a third dose of the COVID-19 vaccine. RESULTS: In total, 94.3% (1742/1847) of the adolescents intended to accept the third dose of the COVID-19 vaccine. Age between 15-17 years, no worry about vaccine safety, confidence for vaccine effectiveness, and supporting opinion from parents were independently associated with acceptance of the third dose (p < 0.05). CONCLUSIONS: It is necessary for governments and school administrators to raise adolescents' and parents' awareness of the benefits and safety of the third dose of vaccination, which should be effective to increase the vaccination coverage among adolescents.

The role of children in household transmission of COVID-19: a systematic review and meta-analysis.

OBJECTIVES: To explore household transmissibility of SARS-CoV-2 in children in new-variants dominating periods. METHODS: Through retrieval in PubMed and Embase, studies were included in two parts: meta-analysis of the household secondary attack rate (SAR) and case analysis of household pediatric infections. RESULTS: A total of 95 articles were included: 48 for meta-analysis and 47 for case analysis. Pediatric COVID-19 only comprised a minority of the household transmission. The total pooled household SAR of child index cases and contacts were 0.20 (95% confidence interval [CI]: 0.15-0.26) and 0.24 (95% CI: 0.18-0.30). Lower household transmissibility was reported in both child index cases and contacts than in adults (relative risk [RR] = 0.64, 95% CI: 0.50-0.81; RR = 0.74, 95% CI: 0.64-0.85). Younger children were as susceptible as the older children (RR = 0.89, 95% CI: 0.72-1.10). Through subgroup analyses of different variants and periods, increased household SAR was observed in children (Wild: 0.20; Alpha: 0.42; Delta: 0.35; Omicron: 0.56), and no significant difference was found in household SAR between children and adults when new variants dominated. CONCLUSION: Although children were found not to be dominant in the household transmission, their transmissibility of SARS-CoV-2 appeared to be on the rise as new variants emerged.

Safety, Immunogenicity, and Efficacy of COVID-19 Vaccines in Adolescents, Children, and Infants: A Systematic Review and Meta-Analysis.

Background: As the epidemic progresses, universal vaccination against COVID-19 has been the trend, but there are still some doubts about the efficacy and safety of COVID-19 vaccines in adolescents, children, and even infants. Purpose: To evaluate the safety, immunogenicity, and efficacy of COVID-19 vaccines in the population aged 0-17 years. Method: A comprehensive search for relevant randomized controlled trials (RCTs) was conducted in PubMed, Embase, and the Cochrane Library from inception to November 9, 2021. All data were pooled by RevMan 5.3 statistical software, with risk ratio (RR) and its 95% confidence interval as the effect measure. This study protocol was registered on PROSPERO (CRD42021290205). Results: There was a total of six randomized controlled trials included in this systematic review and meta-analysis, enrolling participants in the age range of 3-17 years, and containing three types of COVID-19 vaccines. Compared with mRNA vaccines and adenovirus vector vaccines, inactivated vaccines have a more satisfactory safety profile, both after initial (RR 1.40, 95% CI 1.04-1.90, P = 0.03) and booster (RR 1.84, 95% CI 1.20-2.81, P = 0.005) vaccination. The risk of adverse reactions was significantly increased after the first and second doses, but there was no significant difference between the first two doses (RR 1.00, 95%CI 0.99-1.02, P = 0.60). Nevertheless, the two-dose regimen is obviously superior to the single-dose schedule for immunogenicity and efficacy. After booster vaccination, both neutralizing antibodies (RR 144.80, 95%CI 44.97-466.24, P < 0.00001) and RBD-binding antibodies (RR 101.50, 95%CI 6.44-1,600.76, P = 0.001) reach optimal levels, but the cellular immune response seemed not to be further enhanced. In addition, compared with younger children, older children and adolescents were at significantly increased risk of adverse reactions after vaccination, with either mRNA or inactivated vaccines, accompanied by a stronger immune response. Conclusion: The available evidence suggests that the safety, immunogenicity and efficacy of COVID-19 vaccines are acceptable in people aged 3-17 years. However, there is an urgent need for additional multicenter, large-sample studies, especially in younger children under 3 years of age and even in infants, with long-term follow-up data. Systematic Review Registration: https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42021290205, identifier: CRD42021290205.

Booster COVID-19 vaccination against the SARS-CoV-2 Omicron variant: A systematic review.

There is a wealth of data suggesting that the effectiveness of existing vaccines against the Omicron variant, the most mutated SARS-CoV-2 variant to date, has been substantially reduced if only primary vaccination is administered. Therefore, the effectiveness of booster vaccination against the Omicron variant has become a topic of current interest. We conducted a comprehensive search in PubMed, Embase, and the Cochrane Library to collect various pseudovirus neutralization tests or live virus neutralization tests for the Omicron variant, with serum specimens from booster vaccinees. We extracted neutralization titers for the Omicron variant, the original strain, and the other variants before and after booster vaccination, and then manually calculated the fold increase or decrease in neutralization titers for the Omicron variant relative to the other variants, and the fold increase in neutralization titers for the Omicron variant after booster vaccination compared with that before booster vaccination. In the two-dose vaccination regimen, the neutralization titers against the Omicron variant decreased substantially compared to the original strain and other variants. However, after booster vaccination, both homologous and heterologous booster vaccination, the neutralization of serum antibodies against the Omicron variant was significantly improved, although still lower than that of the original strain and other variants. The booster vaccination program based on existing vaccines can produce broad but incomplete immunity against the Omicron variant.

Parents' and Guardians' Willingness to Vaccinate Their Children against COVID-19: A Systematic Review and Meta-Analysis.

COVID-19 vaccination for children is crucial to achieve herd immunity. This is the first systematic review and meta-analysis to estimate parents' and guardians' willingness to vaccinate their children against COVID-19 and identify the determinants of vaccination intention. Systematic research was performed on the two databases (PubMed and EMBASE) from inception to 6 November 2021. Acceptance rates were pooled by use of a random-effects model and all predictors of vaccine acceptance were identified according to the health belief model (HBM) framework. This analysis was registered with PROSPERO (CRD42021292326) and reported in compliance with the PRISMA guidelines. Of 452 identified records, 29 eligible studies were included (N = 68,327 participants). The estimated worldwide vaccination acceptance rate was 61.40% (95% CI: 53.56-68.69%, I2 = 99.3%), ranging from 21.6% to 91.4% across countries and regions. In the determinant assessment, the age of parents and guardians, access to scientific information and recommendations, routine and influenza vaccination behavior, and the willingness of parents and guardians to vaccinate themselves were potentially significant predictors of the vaccination willingness. Given the limited quality and quantity of included articles, future studies with a rigorous design will be necessary for the confirmation of our findings.

The Effectiveness of Convalescent Plasma for the Treatment of Novel Corona Virus Disease 2019: A Systematic Review and Meta-Analysis.

Background: Coronavirus disease 2019 (COVID-19), sweeping across the world, has created a worldwide pandemic. Effective treatments of COVID-19 are extremely urgent. Objective: To analyze the efficacy and safety of convalescent plasma (CCP) on patients with COVID-19. Methods: All the relevant studies were searched from PubMed, EMBASE,Cochrane library, Scopus, Web of Science, CBM, CNKI, Wan fang, VIP, Medrxiv, Biorxiv, and SSRN on July 19, 2021. PICOS criteria were as follows: (P) the study interests were human subjects with the infection of COVID-19; (I) the intervention of interest was CCP; (C) comparator treatments contained placebo, sham therapy, and standard treatment; (O) the primary outcome was mortality rates by the novel coronavirus. The secondary outcomes included the incidence of serious adverse events, the rate of ICU admission and mechanical ventilation (MV); the length of hospital stay; the duration of MV and ICU stay; the antibody levels, inflammatory factor levels, and viral loads. (S) Only randomized controlled trials (RCTs) of CCP were included. Subanalysis, quality assessment, sensitive analysis, and publication bias were conducted by two reviewers independently. Results: Sixteen RCTs were included and enrolled a total of 16,296 participants in this meta-analysis. The pooled data showed that no significant difference was observed in reducing the rate of overall mortality between CCP treatment group and placebo group (OR 0.96; 95% CI 0.90 to 1.03; p = 0.30; I 2 = 6%). According to the results of subgroup analysis, severe or critical patients with CCP showed significant difference in reducing the 28-day mortality of compared with placebo (OR 0.58, 95% CI 0.36 to 0.93, p = 0.02, I 2 = 0%). CCP groups have a significantly shorter duration of MV compared with the control group (weighted MD -1.00, 95% CI -1.86 to -0.14 d p = 0.02, I 2 = 0%). No significant difference was observed in the length of hospital stay, the duration of ICU, and the rate of ICU and MV. There is no conclusive evidence about the safety of CCP. Conclusion: Convalescent plasma can significantly reduce the 28-day mortality of severe or critical COVID-19 patients and the duration of MV. However, more evidence was needed to prove the safety of convalescent plasma.

Extracorporeal membrane oxygenation (ECMO): does it have a role in the treatment of severe COVID-19? (Coronavirus (COVID-19) collection.)

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has emerged since December 2019 in Wuhan city, and has quickly spread throughout China and other countries. To date, no specific treatment has been proven to be effective for SARS-CoV-2 infection. According to World Health Organization (WHO), management of coronavirus disease 19 (COVID-19) has mainly focused on infection prevention, case detection and monitoring, and supportive care. Given to the previous experience, extracorporeal membrane oxygenation (ECMO) has been proven to be an effective therapy in the treatment of respiratory failure or acute respiratory distress syndrome (ARDS). On the basis of similar principle, ECMO may be also an effective therapy in the treatment of severe COVID-19. In this study, we described and discussed the clinical outcomes of ECMO for ARDS patients, ECMO use for severe COVID-19 in China, the indications of ECMO use, and some important issues associated with ECMO.

Extracorporeal membrane oxygenation (ECMO) for critically ill patients with coronavirus disease 2019 (COVID-19): A retrospective cohort study.

PURPOSE: The role of extracorporeal membrane oxygenatio (ECMO) for rescue therapy of respiratory failure in critically ill coronavirus disease 2019 (COVID-19) patients remains controversial. We aimed to evaluate the clinical outcomes of ECMO in the treatment of COVID-19 compared with conventional ventilation support. METHODS: In this retrospective cohort study, data were collected on extremely critical patients with COVID-19 from January 2020 to March 2020 in intensive care unit of a hospital in charge by national rescue team in Wuhan, China, the epicenter of pandemic. Patients were classified into the ECMO group and the conventional ventilation non-ECMO group. Clinical characteristics, technical characteristics, laboratory results, mortality, and complications of the two groups were analyzed. RESULTS: 88 patients with extremely critical COVID-19 were screened; 34 received ECMO support and 31 received conventional ventilation support. Both groups had comparable characteristics at baseline in terms of age, gender, and comorbidities. Before ECMO or conventional therapy, patients in the two groups had sever acute respiratory distress syndrome with a mean partial pressure of arterial oxygen to the fraction of inspired oxygen (PaO2 /FiO2 ) ratio of 69.6 and 75.4, respectively. At the time of reporting, patients in the ECMO had significantly lower in-hospital mortality compared with the control group (58.8 vs. 93.5%, p = .001). CONCLUSION: ECMO is shown to decrease the mortality of extremely critical ill COVID-19 patients compared with the conventional treatment. Although complications occurred frequently, ECMO could still be a rescue therapy for the treatment of COVID-19 during the pandemic.

Psychosocial and behavioral problems of children and adolescents in the early stage of reopening schools after the COVID-19 pandemic: a national cross-sectional study in China.

This study aims to explore the psychosocial and behavioral problems of children and adolescents in the early stage of reopening schools. In this national cross-sectional study, a total of 11072 students from China were naturally divided into two groups based on their schooling status: reopened schools (RS) and home schooling (HS) group. The psychosocial and behavioral functioning were measured by Achenbach Child Behaviour Checklist (CBCL) and compared in these two groups. Multivariable logistic regression analyses were conducted to explore the independent predictors associated with the psychosocial and behavioral problems. Our results showed that the students in the RS group had more adverse behaviors than that of HS group. The RS group had the higher rates of parent-offspring conflict, prolonged homework time, increased sedentary time and sleep problems (all p < 0.001). When separate analyses were conducted in boys and girls, the RS group had the higher scores for (1) overall behavioral problems (p = 0.02 and p = 0.01), internalizing (p = 0.02 and p = 0.02) and externalizing (p = 0.02 and p = 0.004) behaviors in the 6-11 age group; (2) externalizing (p = 0.049 and p = 0.006) behaviors in the 12-16 age group. Multivariable regression showed parent-offspring conflict and increased sedentary time were the most common risk factors, while physical activity and number of close friends were protective factors for behavior problems in RS students (p < 0.01 or 0.05). The present study revealed that students' psychosocial and behavioral problems increased in the early stage of schools reopened unexpectedly. These findings suggest that close attention must be paid and holistic strategies employed in the school reopening process of post-COVID-19 period.

Multi-angle head pose classification with masks based on color texture analysis and stack generalization.

Head pose classification is an important part of the preprocessing process of face recognition, which can independently solve application problems related to multi-angle. But, due to the impact of the COVID-19 coronavirus pandemic, more and more people wear masks to protect themselves, which covering most areas of the face. This greatly affects the performance of head pose classification. Therefore, this article proposes a method to classify the head pose with wearing a mask. This method focuses on the information that is helpful for head pose classification. First, the H-channel image of the HSV color space is extracted through the conversion of the color space. Then use the line portrait to extract the contour lines of the face, and train the convolutional neural networks to extract features in combination with the grayscale image. Finally, stacked generalization technology is used to fuse the output of the three classifiers to obtain the final classification result. The results on the MAFA dataset show that compared with the current advanced algorithm, the accuracy of our method is 94.14% on the front, 86.58% on the more side, and 90.93% on the side, which has better performance.

Mesenchymal Stem Cell-Based Therapy for COVID-19: Possibility and Potential.

A novel coronavirus, named severe acute respiratory syndrome coronavirus 2 (SARS-CoV- 2) has emerged in Wuhan, China since the end of December 2019 and has quickly spread all over the world in a matter of two months. To date, no specific treatment has been proven to be effective for coronavirus (COVID-19). With the rapid increase of infected patients and deaths, it is vital to explore an effective treatment for COVID-19. Current studies suggest that there exists cytokine storm in SARS-CoV-2-infected patients; some of the them will develop acute respiratory distress syndrome (ARDS) and multiple organ dysfunction, and even death. Mesenchymal stem cells (MSCs) possess the property of immunomodulation. Given the previous preclinical and clinical studies, MSCs therapy has shown safety and efficacy in the treatment of respiratory failure or ARDS. Based on similar principles, MSCs therapy may also be an effective therapy in the treatment of COVID-19. In this study, we summarized the clinical outcomes of MSCs for ARDS patients in some preclinical and clinical studies and discussed the application of MSCs for patients with COVID-19 in China and the related important issues with MSCs used during the outbreak.

Mesenchymal Stromal Cell-Based Therapy: A Promising Approach for Severe COVID-19.

During the outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), many critically ill patients died of severe pneumonia, acute respiratory distress syndrome (ARDS), or multiple organ dysfunction syndrome. To date, no specific treatments have been proven to be effective for coronavirus disease 2019 (COVID-19). In the animal models and clinical applications, mesenchymal stromal/stem cells (MSCs) have been shown safety and efficacy for the treatment of respiratory virus infection through their abilities of differentiation and immunomodulation. Besides, possessing several advantages of MSC-derived extracellular vesicles (EVs) over MSCs, EV-based therapy also holds potential therapeutic effects in respiratory virus infection. In this review, we summarized the basic characteristics and mechanisms of COVID-19 and MSCs, outlined some preclinical and clinical studies of MSCs or MSC-EVs for respiratory virus infection such as influenza virus and SARS-CoV-2, shed light on the common problems that we should overcome to translate MSC therapy into clinical application, and discussed some safe issues related to the use of MSCs.

Multisystem inflammatory syndrome in children during the coronavirus disease 2019 (COVID-19) pandemic: a systematic review of published case studies.

BACKGROUND: Many cases have been reported recently on multisystem inflammatory syndrome in children (MIS-C), a newly emerged disease that seemed to correlate with coronavirus disease 2019 (COVID-19). The aim of this review was to describe the clinical features, treatment and outcomes of MIS-C, as well as to assess the risk of bias of published case studies, analyzing their reporting quality. METHODS: We searched all articles reporting on multisystem inflammatory condition in children and adolescents in the context of COVID-19 through MEDLINE (via PubMed), Web of Science, China Biology Medicine disc (CBM) and China National Knowledge Infrastructure (CNKI) from their inception to June 17, 2020. We used CARE and IHE checklists to evaluate the risk of bias and quality of the included studies. We combined the data of clinical manifestations, imaging findings, treatments and outcomes using STATA version 15. RESULTS: Twenty-four studies were included, with a total of 270 participants. Most cases were from Europe and the United States, and the terms of MIS-C in different articles were varied. Fever and gastrointestinal symptoms were the most experienced symptoms. Shock, rash, conjunctivitis, lips or oral cavity changes, hand and feet anomalies, and lymphadenopathy were observed, while respiratory symptoms seemed relatively infrequent. Seventy-eight percent to 100% of patients had evidence of SARS-CoV-2 infection, and patients positive for SARS-CoV-2 by serology [86% (95% CI: 78%, 95%)] were more than those by RT-PCR [36% (95% CI: 26%, 46%)]. Most patients had one or more increased inflammatory markers including C-reactive protein (CRP), procalcitonin (PCT), erythrocyte sedimentation rate (ESR), ferritin, interleukin-6 (IL-6), and D-dimer, accompanied by neutrophilia and lymphopenia. Impaired cardiac function was seen from elevated biomarkers and abnormal echocardiography. Intravenous immunoglobulin (IVIG), anticoagulants, inotropic agents and glucocorticoids were the main treatments, along with other intensive supportive care. Overall, the outcomes of MIS-C were favorable, and only one death was recorded. In terms of the quality assessment of included studies, most of the case studies did not follow the standard reporting checklist, so that they failed to get higher scores in the risk of bias assessment. CONCLUSIONS: Patients with MIS-C present with symptoms more severe than children with COVID-19, with fever and gastrointestinal symptoms as the primary manifestations and multisystem involvement, particularly cardiovascular system. Longer follow-up and further researches for the pathophysiology of MIS-C are urgently needed. In addition, attention should be paid to the quality of case studies to improve the completeness and transparency of scientific reports.