Computational analysis of affinity dynamics between the variants of SARS- CoV-2 spike protein (RBD) and human ACE-2 receptor (preprint)

The novel coronavirus SARS-CoV-2 resulted in a significant worldwide health emergency known as the COVID-19 pandemic. This crisis has been marked by the widespread of various variants, with certain ones causing notable apprehension. In this study, we harnessed computational techniques to scrutinize these Variants of Concern (VOCs), including various Omicron subvariants. Our approach involved the utilizing protein structure prediction algorithms and molecular docking techniques, we aim to investigate the effects of mutations within the Receptor Binding Domain (RBD) of SARS-CoV-2 and how these mutations influence its interactions with the human angiotensin-converting enzyme 2 (hACE-2) receptor. Our focus extends to predicting the structural alterations in the RBD of naturally occurring SARS-CoV-2 variants using the tr-Rosetta algorithm. Subsequent docking and binding analysis employing HADDOCK and PRODIGY illuminated crucial interactions occurring at the Receptor-Binding Motif (RBM). Our findings revealed a hierarchy of increased binding affinity between the human ACE2 receptor and the various RBDs, in the order of wild type (Wuhan-strain) < Beta < Alpha < Gamma < Omicron-B.1.1.529 < Delta < Omicron-BA.2.12.1 < Omicron-BA.5.2.1 < Omicron-BA.1.1. Notably, Omicron-BA.1.1 demonstrated the highest binding affinity of -17.4 kcal mol− 1 to the hACE2 receptor when compared to all the mutant complexes. Additionally, our examination indicated that mutations occurring in active residues of the Receptor Binding Domain (RBD) consistently improved the binding affinity and intermolecular interactions in all mutant complexes. Analyzing the differences among variants has laid a foundation for the structure-based drug design targeting the RBD region of SARS-CoV-2.

Cross-neutralizing antibody against emerging Omicron subvariants of SARS-CoV-2 in infection-naïve individuals with homologous BNT162b2 or BNT162b2(WT+ BA.4/5) bivalent booster vaccination (preprint)

Since the emergence of SARS-CoV-2, different variants and subvariants successively emerged to dominate global virus circulation as a result of immune evasion, replication fitness or both. COVID-19 vaccines continue to be updated in response to the emergence of antigenically divergent viruses, the first being the bivalent RNA vaccines that encodes for both the Wuhan-like and Omicron BA.5 subvariant spike proteins. Repeated infections and vaccine breakthrough infections have led to complex immune landscapes in populations making it increasingly difficult to assess the intrinsic neutralizing antibody responses elicited by the vaccines. Hong Kong’s intensive COVID-19 containment policy through 2020–2021 permitted us to identify sera from a small number of infection naïve individuals who received 3 doses RNA vaccine BNT162b2 of vaccines encoding the Wuhan-like spike who were boosted with a fourth dose monovalent Wuhan-like (WT) vaccine or the bivalent Wuhan-like and BA.4/5 spike (WT + BA.4/5) expressing vaccine. While neutralizing antibody to wild-type virus was comparable in both vaccine groups, BNT162b2 bivalent vaccine elicited significantly higher plaque neutralizing antibodies to Omicron subvariants BA.5, XBB.1.5, XBB.1.16, XBB.1.9.1, XBB.2.3.2, EG.5.1, HK.3, BA.2.86 and JN.1, compared to BNT162b2 monovalent vaccine. The single amino acid substitution that differentiates the spike of JN.1 from BA.2.86 resulted in a profound antigenic change.

Incidence and outcome of covid-19 in AIRD patients on concomitant treatment with tofacitinib-results from KRA covid cohort (KRACC) subset

Background: We assessed the risk factors and outcome of COVID-19 in patients with autoimmune rheumatic diseases (AIRD) who contracted infection while on background treatment with tofacitinib. Method(s): This is a non-interventional, cross-sectional, questionnaire based telephonic study which included consecutive AIRD patients on tofacitinib co-treatment. Data related to the AIRD subset, disease modifying anti rheumatic drugs (DMARDs) including glucocorticoids and comorbidities, was collected from 7 rheumatology centers across Karnataka during the second wave of COVID-19 pandemic. The information about COVID-19 occurrence and COVID-19 vaccination was recorded. Result(s): During the study period (June-July 2021), 335 AIRD patients (80.6% female) on treatment with tofacitinib were included. The mean duration of tofacitinib use was 3.4 +/- 3.1 months. Thirty-six (10.75%) patients developed COVID-19. Diabetes mellitus P = 0.04 (OR 2.60 [1.13-5.99]) was identified as a risk factors for COVID-19 in our cohort. Almost half of our cohort was COVID-19 vaccinated with at least one dose, with resultant decline in incidence of COVID-19 (OR 0.15 [0.06-0.39]) among the vaccinated. Recovery among COVID-19 infection group was 91.2%. Conclusion(s): The AIRD patients on co-treatment with tofacitinib had a higher incidence of COVID-19 than the general population during the same time period. Diabetes mellitus was identified as an independent risk factor in our cohort. COVID-19 vaccinated patients contracted COVID-19 at a significantly lesser rate than the non-vaccinated patients.

Plasma Proteome of Long-covid Patients Indicates Hypoxia-mediated Vasculo-proliferative Disease With Impact on Brain and Heart Function (preprint)

Aims Long-COVID occurs after SARS-CoV-2 infection and results in diverse, prolonged symptoms. The present study aims to determine the underlying mechanisms, and to inform prognosis and treatment.Methods Plasma proteome from Long-COVID outpatients was analyzed in comparison to acutely ill COVID-19 (mild and severe) inpatients and healthy control subjects. The expression of approximately 3000 protein biomarkers was determined with proximity extension assays and then deconvoluted with multiple bioinformatics tools into both cell types and signaling mechanisms, as well as organ specificity.Results Compared to age- and sex-matched acutely ill COVID-19 inpatients and healthy control subjects, Long-COVID outpatients showed natural killer cells with a resting phenotype, as opposed to active, and neutrophils that formed extracellular traps. This resetting of cell phenotypes was reflected in vascular events mediated by both angiopoietin-1 (ANGPT1) and vascular-endothelial growth factor-A (VEGFA). Levels of ANGPT1 and VEGFA were validated by serological methods in different patient cohorts. Silent signaling of transforming growth factor-β1 with elevated EP300 favored not only vascular inflammation, but also tumor necrosis factor-α driven pathways. In addition, a vascular proliferative state associated with hypoxia inducible factor 1 pathway was predicted that progressed from COVID-19 to Long-COVID. The vasculo-proliferative process identified in Long-COVID was associated with significant changes in the organ-specific proteome reflective of neurological and cardiometabolic dysfunction.Conclusions Taken together, our study uncovered a vasculo-proliferative process in Long-COVID initiated by prior hypoxia, and identified potential organ-specific prognostic biomarkers and therapeutic targets.

E-learning course recommendation based on sentiment analysis using hybrid Elman similarity

Online learning is also referred to as E-learning which has gained huge attention and attracted most people during the COVID-19 lockdowns. Due to the excess of online information, users face severe challenges and difficulties realizing the best course that is being competitive in the global market. Therefore, it is necessary to develop an online recommendation system that supports the users in selecting the finest course with E-learning. Thus, the proposed work develops a robust RS model using different approaches. Initially, the pre-processing stage is performed to reduce the presented noise in the website data. Then, the feature extraction stage is done to extract the needed features using Improved TF-IDF, W2V (Word 2 Vector), and Hybrid N-gram. Finally, Elman Minimal Redundancy Maximum Relevance and Enhanced Aquila Optimization (EMRMR_EAO) model is proposed to provide Robust course recommendations. In this work, the ERNN method is used to classify the sentiments based on the similarity measure of the MRMR model. The top course recommendation is afforded depending on the similarity scores like Jaccard similarity, cosine similarity and euclidean similarity. Also, the loss function in the classifier is reduced by optimizing the weight parameters using the EAO approach. The performance analysis shows that the proposed recommendation model obtains improved results in terms of accuracy of 99.98%, recall of 99.81%, precision of 99.65%, and F-measure of 99.95%. The comparative analysis exhibit that the proposed EMRMR_EAO model attains better performance than the other existing works in the literature.

Detection of Genomic Variations of SARS‐CoV‐2 on the S‐Gene in the Orange County, CA Population

Severe Acute Respiratory Syndrome Coronavirus 2 (SARS‐CoV‐2), more commonly known as COVID‐19, is a virus that has spread at a rapid rate beginning in 2019 causing a pandemic. Currently, we remain in this pandemic, and as this virus progresses it is creating mutations of itself, called variants. With these variants, it has become increasingly difficult to control COVID‐19 and keep track of new variants that continue to infect people everywhere. In Orange County, California, COVID‐19 and its variants have enabled county wide shut downs and thousands of infections and deaths. To investigate its devastating effect, five positive COVID‐19 nasal samples were collected between February 2021 to July 2021, and the RNA was extracted. After extraction, a Reverse Transcription Polymerase Chain Reaction (RT‐PCR) was done to amplify 1,727 base pairs of the S‐ Gene within the COVID‐19 genome and was sent to sequencing. These sequences were then aligned using the Basic Local Alignment Search Tool (BLAST) and compared to the original COVID‐19 S‐Gene genome to analyze possible variations. Within the five samples, 30 different mutations were detected and a phylogenetic tree was generated. Awareness of the genetic variation of SARS‐CoV‐2 provides potential future development for more effective targeted research.

Therapeutic Management of COVID-19 in a Pediatric Patient with Neurodegenerative CLN2 Disease and ICV-Enzyme Replacement Therapy: A Case Report.

The 12 years old male patient presented here suffers from neuronal ceroid lipofuscinoses 2 (CLN2) (MIM# 204500) and receives intracerebroventricular enzyme replacement therapy (ICV-ERT) every 14 days. After the emergence of the coronavirus disease 2019 (COVID-19) pandemic, routine care of children and adolescents with rare chronic diseases has become challenging. Although, in general, children do not develop severe COVID-19, when severe acute respiratory syndrome coronavirus 2 infection was detected by polymerase chain reaction-screening examination in our CLN2 patient before hospital admission for ICV-ERT, he was regarded to be at risk. Upon diagnosis, the patient developed respiratory deterioration symptoms and was admitted to our pediatric intensive care unit to receive oxygen, remdesivir, and steroids. As far as we know, this is the first CLN2 patient receiving intraventricular enzyme therapy with COVID-19 who required intensive care treatment and specific therapy.

The association of ABO and Rhesus blood type with the risks of developing SARS-CoV-2 infection: A meta-analysis.

Coronavirus Disease 2019 (COVID-19) has been spreading like a wildfire everywhere in the globe. It has been challenging the global health care system ever since the end of 2019, with its virulence and pathogenicity. Recent studies have shown the association between ABO blood group, Rhesus blood type and susceptibility to COVID-19 infection. Various studies and few meta-analyses have been done and some might be inconsistent; therefore, this meta-analysis was done to assess the relationship between different ABO and Rhesus blood types on the susceptibility to COVID-19 infections. This meta-analysis assessed the odds ratio of COVID-19 infection of different ABO and Rhesus blood types. Subgroup analyses according to (1) age and gender matched; (2) different blood group antigens; (3) Rhesus positive and negative of each blood group were carried out. Publication bias and Quality Assessment of Diagnostic Accuracy Studies-2 (QUADAS-2) were also done to assess the risk of bias in these publications. It was found that blood group A showed significant difference in odds ratio of COVID-19 infection (OR, 1.16; 95% CI, 1.08-1.24). Blood group AB showed significant difference in odds ratio when studies with lower QUADAS-2 score were removed. This means that populations with blood group A and AB are more likely to be infected with COVID-19. As there is a higher tendency that blood group A and AB to be infected with COVID- 19, precautious care should be taken by these populations.

SARS-CoV-2 infection induces inflammatory bone loss in golden Syrian hamsters (preprint)

Extrapulmonary complications of different organ systems have been increasingly recognized in patients with severe or chronic Coronavirus Disease 2019 (COVID-19). However, limited information on the skeletal complications of COVID-19 is known, even though inflammatory diseases of the respiratory tract have been known to perturb bone metabolism and cause pathological bone loss. In this study, we characterized the effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection on bone metabolism in an established golden Syrian hamster model for COVID-19. SARS-CoV-2 causes significant multifocal loss of bone trabeculae in the long bones and lumbar vertebrae of all infected hamsters. The bone loss progressively worsens from the acute phase to the post-recovery phase. Mechanistically, the bone loss was associated with SARS-CoV-2-induced cytokine dysregulation which upregulates osteoclastic differentiation of monocyte-macrophage lineage. The pro-inflammatory cytokines further trigger a second wave of cytokine storm in the skeletal tissues to augment their pro-osteoclastogenesis effect. Our findings in this established hamster model suggest that pathological bone loss may be a neglected complication which warrants more extensive investigations during the long-term follow-up of COVID-19 patients. The benefits of potential prophylactic and therapeutic interventions against pathological bone loss should be further evaluated. O_FIG O_LINKSMALLFIG WIDTH=188 HEIGHT=200 SRC="FIGDIR/small/463665v1_ufig1.gif" ALT="Figure 1"> View larger version (81K): org.highwire.dtl.DTLVardef@c5b1d6org.highwire.dtl.DTLVardef@11e8728org.highwire.dtl.DTLVardef@13b8902org.highwire.dtl.DTLVardef@1a00cfe_HPS_FORMAT_FIGEXP M_FIG C_FIG Graphical abstractSARS-CoV-2 infection causes pathological bone loss in golden Syrian hamsters through induction of cytokine storm and inflammation-induced osteoclastogenesis.

Air dispersal of multidrug-resistant Acinetobacter baumannii: implications for nosocomial transmission during the COVID-19 pandemic.

AIM: To describe the nosocomial transmission of Air, multidrug-resistant, Acinetobacter baumannii, nosocomial, COVID-19 Acinetobacter baumannii (MRAB) in an open-cubicle neurology ward with low ceiling height, where MRAB isolates collected from air, commonly shared items, non-reachable high-level surfaces and patients were analysed epidemiologically and genetically by whole-genome sequencing. This is the first study to understand the genetic relatedness of air, environmental and clinical isolates of MRAB in the outbreak setting. FINDINGS: Of 11 highly care-dependent patients with 363 MRAB colonization days during COVID-19 pandemic, 10 (90.9%) and nine (81.8%) had cutaneous and gastrointestinal colonization, respectively. Of 160 environmental and air samples, 31 (19.4%) were MRAB-positive. The proportion of MRAB-contaminated commonly shared items was significantly lower in cohort than in non-cohort patient care (0/10, 0% vs 12/18, 66.7%; P<0.001). Air dispersal of MRAB was consistently detected during but not before diaper change in the cohort cubicle by 25-min air sampling (4/4,100% vs 0/4, 0%; P=0.029). The settle plate method revealed MRAB in two samples during diaper change. The proportion of MRAB-contaminated exhaust air grills was significantly higher when the cohort cubicle was occupied by six MRAB patients than when fewer than six patients were cared for in the cubicle (5/9, 55.6% vs 0/18, 0%; P=0.002). The proportion of MRAB-contaminated non-reachable high-level surfaces was also significantly higher when there were three or more MRAB patients in the cohort cubicle (8/31, 25.8% vs 0/24, 0%; P=0.016). Whole-genome sequencing revealed clonality of air, environment, and patients' isolates, suggestive of air dispersal of MRAB. CONCLUSIONS: Our findings support the view that patient cohorting in enclosed cubicles with partitions and a closed door is preferred if single rooms are not available.

[Mild COVID-19 disease in healthcare workers at a German university clinic : The "first wave" at the University Medical Center Hamburg-Eppendorf]. / Milde COVID-19-Verläufe bei Mitarbeitenden einer Universitätsklinik : Die "erste Welle" am Universitätsklinikum Hamburg-Eppendorf.

BACKGROUND: Healthcare workers are among the most exposed and potentially most threatened populations of the ongoing COVID-19 pandemic. Despite some reports on numbers of infections with SARS-CoV­2 in German healthcare workers, the courses of their clinical presentation when affected by COVID-19 are not well described. OBJECTIVE: In this contribution, characteristics and progressions of infected cases among healthcare workers at the University Medical Center Hamburg-Eppendorf during the first wave of the COVID-19 pandemic will be presented. METHODS: Between 1 July and 28 July 2020, 67 healthcare workers, who previously tested positive for SARS-CoV­2 via PCR, were invited via E­mail to participate in an anonymous online questionnaire; 39 persons participated. RESULTS: Participants (58%) were mostly ≤ 39 years old (64%) and female (70%). Most healthcare workers were involved in direct patient management (85%), including contact with SARS-CoV­2 positive patients (62%). All participants reported acute symptoms with a median duration of 19 days. The most frequent symptoms were fatigue (85%), anosmia (67%), cough (64%), headache (62%), and shortness of breath (51%). The disease course was mostly mild with low admission rates (5%). Ongoing symptoms lasting more than four weeks post-symptom-onset, particularly anosmia, fatigue, and shortness of breath, were reported by 38%. This group more frequently had pre-existing conditions (53% vs. 12%, p = 0.010), specifically hypertension (27% vs. 4%, p = 0.062). DISCUSSION: Healthcare workers reported mostly mild courses of COVID-19 despite increased contact with SARS-CoV-2 patients. However, some reported persistent symptoms months after infection.

Fighting the SARS CoV-2 (COVID-19) Pandemic with Soap (preprint)

The greatest pandemic of the century, COVID-19, is an ongoing global public health problem. With a clinically approved treatment available only for those who are acutely ill and are hospitalized, the control of this disease in the general population is still largely dependent on the preventive measures issued by the World Health Organization. Among the general control measures other than immunization with the COVID-19 vaccines, handwashing with soap and water has been emphasized the most because it is cost-effective and easily accessible to the general public. Studies have reported that soaps offer unique chemical properties that can completely destroy enveloped viruses. However, the general public seems to be still uncertain about whether soaps can shield us from a highly contagious disease such as COVID-19. In an attempt to help eliminate the uncertainty, we analyzed the mechanisms underlying the efficacy of soap and its prospect for preventing the spread of COVID-19. In this paper, we provide an overview of the history and characteristics of the SARS-CoV-2 virus, the current global COVID-19 situation, the possible mechanisms of the deactivation of viruses by soaps, and the potential effectiveness of soap in eliminating coronaviruses including SARS-CoV-2.

Age-Based Disparities in Hospitalizations and Mortality for Coronavirus Disease 2019 (COVID-19) (preprint)

Purpose: Evidence suggests that older adults, racial/ethnic minorities, and those with comorbidities all face elevated risk for morbidity and mortality from COVID-19; but there are limited reports describing the potential for interactions between these factors. Methods: We sought to evaluate age-based heterogeneity in observed disparities in hospitalization, ICU admission, and mortality related to COVID-19 using CDC public use surveillance data on 3,662,325 COVID-19 cases reported from January 1 to August 30, 2020. Results: Racial/ethnic and comorbidity disparities in hospitalization were most pronounced during ages 20-29 and ages 10-19, with similar elevation seen for disparities in ICU risk. Racial/ethnic disparities in mortality were most pronounced during ages 20-29 while risk from comorbidity peaks among ages 10-39. Conclusions: As COVID-19 continues to affect younger populations, special attention to the implications for the most vulnerable subgroups are clearly warranted.

Newly designed analogues from SARS-CoV inhibitors mimicking the druggable properties against SARS-CoV-2 and its novel variants (preprint)

The emerging variants of SARS Coronavirus-2 (SARS-CoV-2) has been continuously spreading all over the world and raised global health concerns. The B.1.1.7 (United Kingdom), P.1 (Brazil), B.1.351 (South Africa) and B.1.617 (India) variants resulted due to multiple mutations in the spike glycoprotein (SGp), are resistant to neutralizing antibodies and enable increased transmission. Hence, new drugs might be of great importance against the novel variants of SARS-CoV-2. The SGp and main protease (Mpro) of SARS-CoV-2 are important targets to design and develop antiviral compounds for new drug discovery. In this study, we selected seventeen phytochemicals and later performed molecular docking to determine the binding interactions of the compounds with the two receptors and calculated several drug likeliness properties for each compound. Luteolin, myricetin and quercetin demonstrated higher affinity for both the proteins and interacted efficiently. To get better compounds, we designed three analogues from these compounds and showed the greater druggable properties than the parent compounds. Furthermore, we found that the analogues bind to the residues of both proteins including the recent novel variants of SARS-CoV-2. The binding study was further verified by molecular dynamics (MD) simulation and molecular mechanics/Poisson Boltzmann surface area (MM/PBSA) approaches by assessing the stability of the complexes. MD simulations revealed that Arg457 of SGp and Met49 of Mpro are the most important residues that interacted with the designed inhibitors. Our analysis may give some breakthroughs to develop new therapeutics to treat the proliferation of SARS-CoV-2 in vitro and in vivo.

Demographic benchmarks for equitable coverage of the COVID-19 vaccination program among priority populations (preprint)

We report the demographic distribution of non-institutionalized populations in the US who are prioritized for COVID-19 vaccination by ethnicity, age and sex and region. The composition of non-institutionalized priority populations was estimated using a nationally representative sample of 25,417 adults interviewed in the National Health Interview Survey (NHIS) in 2018. A relatively large fraction of individuals prioritized for the earliest distribution of the vaccine are women, non-Hispanic Black, and young to middle aged adults. Overall, the study provides a platform to track equity in vaccine coverage and to better tailor health communication strategies.

iWorkSafe: Towards Healthy Workplaces during COVID-19 with an Intelligent pHealth App for Industrial Settings (preprint)

The recent outbreak of the novel Coronavirus Disease (COVID-19) has given rise to diverse health issues due to its high transmission rate and limited treatment options. Almost the whole world, at some point of time, was placed in lock-down in an attempt to stop the spread of the virus, with resulting psychological and economic sequela. As countries start to ease lock-down measures and reopen industries, ensuring a healthy workplace for employees has become imperative. Thus, this paper presents a mobile app-based intelligent portable healthcare (pHealth) tool, called iWorkSafe, to assist industries in detecting possible suspects for COVID-19 infection among their employees who may need primary care. Developed mainly for low-end Android devices, the iWorkSafe app hosts a fuzzy neural network model that integrates data of employees' health status from the industry's database, proximity and contact tracing data from the mobile devices, and user-reported COVID-19 self-test data. Using the built-in Bluetooth low energy sensing technology and K Nearest Neighbor and K-means techniques, the app is capable of tracking users’ proximity and trace contact with other employees. Additionally, it uses a logistic regression model to calculate the COVID-19 self-test score and a Bayesian Decision Tree model for checking real-time health condition from intelligent e-health platform for further clinical attention of the employees. Rolled out in an apparel factory on 12 employees as a test case, the pHealth tool generates an alert to maintain social distancing among employees inside the industry. In addition, the app helps employee to estimate risk with possible COVID-19 infection based on the collected data and found that the score is effective in estimating personal health condition of the app user.

Health, Psychosocial, and Economic Impacts of the Covid-19 Pandemic on People with Chronic Conditions in India: A Mixed Methods Study (preprint)

Background: People with chronic conditions are disproportionately prone to be affected by the COVID-19 pandemic but there are limited data documenting this. We aimed to assess the health, psychosocial and economic impacts of the COVID-19 pandemic on people with chronic conditions in India.Methods: Between July 29, to September 12, 2020, we telephonically surveyed adults (n=2335) with chronic conditions across four sites in India. Data on participants’ demographic, socio-economic status, comorbidities, access to health care, treatment satisfaction, self-care behaviors, employment, and income were collected using pre-tested questionnaires. We performed multivariable logistic regression analysis to examine the correlates of difficulty in accessing medicines and worsening of diabetes or hypertension symptoms. Further, a diverse sample of 40 participants completed qualitative interviews that focused on eliciting patient’s experiences during the COVID-19 lockdowns and data analysed using thematic analysis.Findings: 1,734 individuals completed the survey (response rate=74%). The mean (SD) age of respondents was 57·8 years (11·3) and 50% were men. During the COVID-19 lockdowns in India, 83% of participants reported difficulty in accessing healthcare, 17% faced difficulties in accessing medicines, 59% reported loss of income, 38% lost jobs, and 28% reduced fruit and vegetable consumption. In the final-adjusted regression model, rural residence (OR, 95%CI: 4·01,2·90-5·53), having diabetes (2·42, 1·81-3·25) and hypertension (1·70,1·27-2·27), and loss of income (2·30,1·62-3·26) were significantly associated with difficulty in accessing medicines. Further, difficulties in accessing medicines (3·67,2·52-5·35), and job loss (1·90,1·25-2·89) were associated with worsening of diabetes or hypertension symptoms. Qualitative data suggest most participants experienced psychosocial distress due to loss of job or income and had difficulties in accessing in-patient services.Interpretation: People with chronic conditions, particularly among poor, rural, and marginalized populations, have experienced difficulties in accessing healthcare and been severely affected both socially and financially by the COVID-19 pandemic.Funding: None.Declaration of Interests: No conflict of interest to declare.Ethics Approval Statement: This study was approved by the Institutional Ethics Committees of the Centre for Chronic Disease Control, New Delhi, India, and the Madras Diabetes Research Foundation, Chennai, India. All participants provided verbal consent to this study over the phone.

Home-made masks with filtration efficiency for nano-aerosols for community mitigation of COVID-19 pandemic.

OBJECTIVES: The novel coronavirus disease 2019 (COVID-19) epidemic that emerged in December 2019 has rapidly evolved in recent months to become a worldwide and ongoing pandemic. Shortage of medical masks remains an unresolved problem. This study aims to investigate the filtration efficiency (FE) of home-made masks that could be used as alternatives for community mitigation of COVID-19. STUDY DESIGN: Experimental observational analytic study. METHODS: The FE of home-made masks and medical masks (as the control) were tested under laminar flow within a scaled air duct system using nebulised NaCl aerosols sized 6-220 nm. The size-resolved NaCl aerosol count was measured using a scanning mobility particle-sizer spectrometer. Home-made masks with an external plastic face shield also underwent a splash test. In addition, the fibre structures of medical masks were studied under an electron microscope after treatment with either 75% alcohol or soap and water at 60 °C. RESULTS: The FE of the home-made masks at 6-200 nm were non-inferior to that of medical masks (84.54% vs 86.94%, P = 0.102). Both types of masks achieved an FE of 90% at 6-89 nm. A significantly higher FE was achieved when one piece of tissue paper was added adjacent to the inner surface of the medical mask than medical mask alone (6-200 nm: 91.64% vs 86.94%, P < 0.0001; 6-89 nm: 94.27% vs 90.54%, P < 0.0001; 90-200 nm: 82.69% vs 73.81%, P < 0.0001). The plastic face shield prevented the home-made mask from fluid splash. The fibre structures of the external surface of medical masks were damaged after treatment with either 75% alcohol or soap and water at 60 °C. CONCLUSIONS: The home-made masks in this study, which were made of one piece of tissue paper and two pieces of kitchen towels, layered from face to external, had an FE at 6-200 nm non-inferior to that of medical mask materials, which had a certified FE of ≥95% at 3 µm. In the current COVID-19 pandemic with the shortage of medical masks, these home-made masks combined with an external plastic shield could be used as an alternative to medical masks for community mitigation. In addition, one piece of tissue paper could be placed adjacent to the inner surface of a medical mask to prolong effective lifespan of the medical mask. These demand reduction strategies could be used to reserve medical masks for use in healthcare and certain high-risk community settings, such as symptomatic persons, caregivers and attendees to healthcare institutions.