Masks for COVID-19.

Sustainable solutions on fabricating and using a face mask to block the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spread during this coronavirus pandemic of 2019 (COVID-19) are required as society is directed by the World Health Organization (WHO) toward wearing it, resulting in an increasingly huge demand with over 4 000 000 000 masks used per day globally. Herein, various new mask technologies and advanced materials are reviewed to deal with critical shortages, cross-infection, and secondary transmission risk of masks. A number of countries have used cloth masks and 3D-printed masks as substitutes, whose filtration efficiencies can be improved by using nanofibers or mixing other polymers into them. Since 2020, researchers continue to improve the performance of masks by adding various functionalities, for example using metal nanoparticles and herbal extracts to inactivate pathogens, using graphene to make masks photothermal and superhydrophobic, and using triboelectric nanogenerator (TENG) to prolong mask lifetime. The recent advances in material technology have led to the development of antimicrobial coatings, which are introduced in this review. When incorporated into masks, these advanced materials and technologies can aid in the prevention of secondary transmission of the virus.

Fabrication of a High-Performance and Reusable Planar Face Mask in Response to the COVID-19 Pandemic.

The coronavirus disease 2019 (COVID-19) pandemic has caused a surge in demand for face masks, with the massive consumption of masks leading to an increase in resource-related and environmental concerns. In this work, we fabricated meltblown polypropylene (mb-PP)-based high-performance planar face masks and investigated the effects of six commonly used disinfection methods and various mask-wearing periods on the reusability of these masks. The results show that, after three cycles of treatment using hot water at 70 °C for 30 min, which is one of the most scalable, user-friendly methods for viral disinfection, the particle filtration efficiency (PFE) of the mask remained almost unchanged. After mask wearing for 24 h and subsequent disinfection using the same treatment procedures, the PFE decreased to 91.3%; the average number of bacterial and fungal colonies was assessed to be 9.2 and 51.6 colony-forming units per gram (CFU∙g- 1), respectively; and coliform and pyogenic bacteria were not detected. Both the PFE and the microbial indicators are well above the standard for reusable masks after disinfection. Schlieren photography was then used to assess the capabilities of used and disinfected masks during use; it showed that the masks exhibit a high performance in suppressing the spread of breathed air.

Uncovering a conserved vulnerability site in SARS-CoV-2 by a human antibody.

An essential step for SARS-CoV-2 infection is the attachment to the host cell receptor by its Spike receptor-binding domain (RBD). Most of the existing RBD-targeting neutralizing antibodies block the receptor-binding motif (RBM), a mutable region with the potential to generate neutralization escape mutants. Here, we isolated and structurally characterized a non-RBM-targeting monoclonal antibody (FD20) from convalescent patients. FD20 engages the RBD at an epitope distal to the RBM with a KD of 5.6 nM, neutralizes SARS-CoV-2 including the current Variants of Concern such as B.1.1.7, B.1.351, P.1, and B.1.617.2 (Delta), displays modest cross-reactivity against SARS-CoV, and reduces viral replication in hamsters. The epitope coincides with a predicted "ideal" vulnerability site with high functional and structural constraints. Mutation of the residues of the conserved epitope variably affects FD20-binding but confers little or no resistance to neutralization. Finally, in vitro mode-of-action characterization and negative-stain electron microscopy suggest a neutralization mechanism by which FD20 destructs the Spike. Our results reveal a conserved vulnerability site in the SARS-CoV-2 Spike for the development of potential antiviral drugs.

Targeting lysophospholipid acid receptor 1 and ROCK kinases promotes antiviral innate immunity.

Growing evidence indicates the vital role of lipid metabolites in innate immunity. The lipid lysophosphatidic acid (LPA) concentrations are enhanced in patients upon HCV or SARS-CoV-2 infection, but the function of LPA and its receptors in innate immunity is largely unknown. Here, we found that viral infection promoted the G protein­coupled receptor LPA1 expression, and LPA restrained type I/III interferon production through LPA1. Mechanistically, LPA1 signaling activated ROCK1/2, which phosphorylated IRF3 Ser97 to suppress IRF3 activation. Targeting LPA1 or ROCK in macrophages, fibroblasts, epithelial cells, and LPA1 conditional KO mice promoted interferon-induced clearance of multiple viruses. LPA1 was colocalized with the receptor ACE2 in lung and intestine. Together with previous findings that LPA1 and ROCK1/2 promoted vascular leaking or lung fibrosis, we propose that the current available preclinical drugs targeting the LPA1-ROCK module might protect from SARS-CoV-2 or various virus infections in the intestine or lung.

Comparison of acute pneumonia caused by SARS-COV-2 and other respiratory viruses in children: a retrospective multi-center cohort study during COVID-19 outbreak.

BACKGROUND: Until January 18, 2021, coronavirus disease-2019 (COVID-19) has infected more than 93 million individuals and has caused a certain degree of panic. Viral pneumonia caused by common viruses such as respiratory syncytial virus, rhinovirus, human metapneumovirus, human bocavirus, and parainfluenza viruses have been more common in children. However, the incidence of COVID-19 in children was significantly lower than that in adults. The purpose of this study was to describe the clinical manifestations, treatment and outcomes of COVID-19 in children compared with those of other sources of viral pneumonia diagnosed during the COVID-19 outbreak. METHODS: Children with COVID-19 and viral pneumonia admitted to 20 hospitals were enrolled in this retrospective multi-center cohort study. A total of 64 children with COVID-19 were defined as the COVID-19 cohort, of which 40 children who developed pneumonia were defined as the COVID-19 pneumonia cohort. Another 284 children with pneumonia caused by other viruses were defined as the viral pneumonia cohort. The epidemiologic, clinical, and laboratory findings were compared by Kolmogorov-Smirnov test, t-test, Mann-Whitney U test and Contingency table method. Drug usage, immunotherapy, blood transfusion, and need for oxygen support were collected as the treatment indexes. Mortality, intensive care needs and symptomatic duration were collected as the outcome indicators. RESULTS: Compared with the viral pneumonia cohort, children in the COVID-19 cohort were mostly exposed to family members confirmed to have COVID-19 (53/64 vs. 23/284), were of older median age (6.3 vs. 3.2 years), and had a higher proportion of ground-glass opacity (GGO) on computed tomography (18/40 vs. 0/38, P < 0.001). Children in the COVID-19 pneumonia cohort had a lower proportion of severe cases (1/40 vs. 38/284, P = 0.048), and lower cases with high fever (3/40 vs. 167/284, P < 0.001), requiring intensive care (1/40 vs. 32/284, P < 0.047) and with shorter symptomatic duration (median 5 vs. 8 d, P < 0.001). The proportion of cases with evaluated inflammatory indicators, biochemical indicators related to organ or tissue damage, D-dimer and secondary bacterial infection were lower in the COVID-19 pneumonia cohort than those in the viral pneumonia cohort (P < 0.05). No statistical differences were found in the duration of positive PCR results from pharyngeal swabs in 25 children with COVID-19 who received antiviral drugs (lopinavir-ritonavir, ribavirin, and arbidol) as compared with duration in 39 children without antiviral therapy [median 10 vs. 9 d, P = 0.885]. CONCLUSION: The symptoms and severity of COVID-19 pneumonia in children were no more severe than those in children with other viral pneumonia. Lopinavir-ritonavir, ribavirin and arbidol do not shorten the duration of positive PCR results from pharyngeal swabs in children with COVID-19. During the COVID-19 outbreak, attention also must be given to children with infection by other pathogens infection.

An Antioxidant Enzyme Therapeutic for COVID-19.

The COVID-19 pandemic has taken a significant toll on people worldwide, and there are currently no specific antivirus drugs or vaccines. Herein it is a therapeutic based on catalase, an antioxidant enzyme that can effectively breakdown hydrogen peroxide and minimize the downstream reactive oxygen species, which are excessively produced resulting from the infection and inflammatory process, is reported. Catalase assists to regulate production of cytokines, protect oxidative injury, and repress replication of SARS-CoV-2, as demonstrated in human leukocytes and alveolar epithelial cells, and rhesus macaques, without noticeable toxicity. Such a therapeutic can be readily manufactured at low cost as a potential treatment for COVID-19.

Can Masks Be Reused After Hot Water Decontamination During the COVID-19 Pandemic?

Masks have become one of the most indispensable pieces of personal protective equipment and are important strategic products during the coronavirus disease 2019 (COVID-19) pandemic. Due to the huge mask demand-supply gap all over the world, the development of user-friendly technologies and methods is urgently needed to effectively extend the service time of masks. In this article, we report a very simple approach for the decontamination of masks for multiple reuse during the COVID-19 pandemic. Used masks were soaked in hot water at a temperature greater than 56 °C for 30 min, based on a recommended method to kill COVID-19 virus by the National Health Commission of the People's Republic of China. The masks were then dried using an ordinary household hair dryer to recharge the masks with electrostatic charge to recover their filtration function (the so-called "hot water decontamination + charge regeneration" method). Three kinds of typical masks (disposable medical masks, surgical masks, and KN95-grade masks) were treated and tested. The filtration efficiencies of the regenerated masks were almost maintained and met the requirements of the respective standards. These findings should have important implications for the reuse of polypropylene masks during the COVID-19 pandemic. The performance evolution of masks during human wear was further studied, and a company (Zhejiang Runtu Co., Ltd.) applied this method to enable their workers to extend the use of masks. Mask use at the company was reduced from one mask per day per person to one mask every three days per person, and 122 500 masks were saved during the period from 20 February to 30 March 2020. Furthermore, a new method for detection of faulty masks based on the penetrant inspection of fluorescent nanoparticles was established, which may provide scientific guidance and technical methods for the future development of reusable masks, structural optimization, and the formulation of comprehensive performance evaluation standards.