Transmission of COVID-19 virus by droplets and aerosols: A critical review on the unresolved dichotomy

Review of research advances in microbial sterilization technologies and applications in the built environment

As globalization accelerates, microbial contamination in the built environment poses a major public health challenge. Especially since Corona Virus Disease 2019 (COVID-19), microbial sterilization technology has become a crucial research area for indoor air pollution control in order to create a hygienic and safe built environment. Based on this, the study reviews sterilization technologies in the built environment, focusing on the principles, efficiency and applicability, revealing advantages and limitations, and summarizing current research advances. Despite the efficacy of single sterilization technologies in specific environments, the corresponding side effects still exist. Thus, this review highlights the efficiency of hybrid sterilization technologies, providing an in-depth understanding of the practical application in the built environment. Also, it presents an outlook on the future direction of sterilization technology, including the development of new methods that are more efficient, energy-saving, and targeted to better address microbial contamination in the complex and changing built environment. Overall, this study provides a clear guide for selecting technologies to handle microbial contamination in different building environments in the future, as well as a scientific basis for developing more effective air quality control strategies.

COVID-19 dynamic modeling of immune variability and multistage vaccination strategies: A case study in Malaysia

Hybrid-immune and immunodeficient individuals have been identified by the World Health Organization as two vulnerable groups in the context of COVID-19, but their distinct characteristics remain underexplored. To address this gap, we developed an extended SIVS compartmental model that simulates the spread of COVID-19 and the impact of administering three doses of the vaccine (first, second, and booster). This study aims to provide insights into how these vulnerable populations respond to vaccination and the dynamics of waning immunity. Using real-time data from the Ministry of Health of Malaysia (May 2023-April 2024), we estimated key parameters through numerical methods and fitted the model to the data using MATLAB's lsqcurvefit package. We carried out stability and equilibrium analyses, computed the basic reproduction number (R 0), and identified conditions for Hopf bifurcation. Sensitivity analysis highlights the parameters with the greatest impact on infection dynamics. The calculated basic reproduction number and stability results suggest that with current vaccination rates, COVID-19 will persist in the population over an extended period. Our findings provide valuable information for public health agencies, offering recommendations for vaccination strategies targeting hybrid-immune and immunodeficient groups. These insights can inform decisions about vaccine booster schedules and resource allocation to better manage the pandemic.

Analysis of SARS-CoV-2 Transmission by Airborne Droplets in a Restaurant Outbreak: A CFD Approach

Restaurants have played a vital role in spreading the respiratory virus due to the invalidation of certain preventive behaviors such as mask wearing. We analyzed a coronavirus disease 2019 (COVID-19) outbreak involving two clusters in a restaurant to analyze SARS-CoV-2 transmission by airborne droplets, including aerosols, in a restaurant outbreak. Computational fluid dynamics (CFD) was used to simulate the spread of respiratory droplets generated by coughing. The cough jet was modeled as a turbulent jet to study the dispersion of expiratory droplets, with the realizable k-ε model being applied in this simulation. This outbreak involved six diners (A, B, D, E, F, and G) in two clusters (X and Y). But the two clusters were seated at two tables separated by over 3 m from each other, while none of the 18 patrons at the other seven tables, even patrons at neighboring tables, became infected. Upon further investigation, we found that the index case in Cluster X coughed violently with his head facing posterior to the right when Diner F entered the restaurant and passed the posterior side of the index case. Adequate droplets were ejected from the index case and were inhaled by Diner F or trapped by the surfaces of Diner F's hands, clothing, and belongings. The virus-laden droplets and aerosols generated by coughing can be responsible for inhalation or contamination of surfaces that they fall onto, leading to spread of the disease.

Comparative Examination of Feline Coronavirus and Canine Coronavirus Effects on Extracellular Vesicles Acquired from A-72 Canine Fibrosarcoma Cell Line

Introduction: Coronavirus (CoV) is an extremely contagious, enveloped positive-single-stranded RNA virus, which has become a global pandemic that causes several illnesses in humans and animals. Hence, it is necessary to investigate viral-induced reactions across diverse hosts. Herein, we propose utilizing naturally secreted extracellular vesicles (EVs), mainly focusing on exosomes to examine virus-host responses following CoV infection. Exosomes are small membrane-bound vesicles originating from the endosomal pathway, which play a pivotal role in intracellular communication and physiological and pathological processes. We suggested that CoV could impact EV formation, content, and diverse immune responses in vitro. Methods: In this study, we infected A-72, which is a canine fibroblast cell line, with a feline coronavirus (FCoV) and canine coronavirus (CCoV) independently in an exosome-free media at 0.001 multiplicity of infection (MOI), with incubation periods of 48 and 72 h. The cell viability was significantly downregulated with increased incubation time following FCoV and CCoV infection, which was identified by performing the 3-(4,5-dimethylthiazo-1-2yl)-2,5-diphenyltetrazolium bromide (MTT) assay. After the infection, EVs were isolated through ultracentrifugation, and the subsequent analysis involved quantifying and characterizing the purified EVs using various techniques. Results: NanoSight particle tracking analysis (NTA) verified that EV dimensions fell between 100 and 200 nm at both incubation periods. At both periods, total protein and RNA levels were significantly upregulated in A-72-derived EVs following FCoV and CCoV infections. However, total DNA levels were gradually upregulated with increased incubation time. Dot blot analysis indicated that the expression levels of ACE2, IL-1β, Flotillin-1, CD63, caspase-8, and Hsp90 were modified in A-72-derived EVs following both CoV infections. Conclusions: Our results indicated that FCoV and CCoV infections could modulate the EV production and content, which could play a role in the development of viral diseases. Investigating diverse animal CoV will provide in-depth insight into host exosome biology during CoV infection. Hence, our findings contribute to the comprehension and characterization of EVs in virus-host interactions during CoV infection.

Infection prevention and control of epidemic-prone acute respiratory infections in healthcare setting

PURPOSE OF REVIEW

The recent COVID-19 pandemic sparked discussions and highlighted significant gaps on the most appropriate infection prevention and control (IPC) measures when dealing with acute respiratory infections (ARIs). This narrative review aims to provide an overview of the existing international and national guidelines on the IPC measures to control epidemic and pandemic-prone ARIs in healthcare settings.

RECENT FINDINGS

The WHO has recently produced a report proposing an updated terminology for respiratory pathogens. One of the key outcomes of this consultation was the adoption of the term 'infectious respiratory particles' (IRPs). According to the report, IRPs are defined as infectious particles that can be expired from an infected person through activities like breathing, talking, singing, coughing, sneezing, or even spitting. Most notably, there is no longer the clear and traditional distinction between droplet and aerosol based on the cut-off of particle size, but rather a continuum of particle sizes of IRPs.

SUMMARY

Among other recommendations, all international guidelines place emphasis on the use of standard and transmission-based precautions when dealing with respiratory viruses. It is important to assess how the new proposed terminology for respiratory pathogens may affect the current existing IPC measures.

Aerosol emission, transmission, and mitigation from performing singing and wind instruments

During the COVID-19 pandemic, concerns about potential airborne virus transmission and exposure during musical performances were raised. Past studies suggest that aerosols are emitted from exhaling and talking with varying magnitudes. Meanwhile, little was known about aerosol emissions from singing and playing wind instruments. The objective of this study was to examine the spatial and temporal build-up of aerosol concentration in a typical studio room where singing, talking, and playing wind instruments are involved, to represent musical practicing and teaching scenarios at the University of Cincinnati College-Conservatory of Music (CCM). Four condensation particle counters were strategically placed throughout a room at various distances from the performer. Besides singing, musical professionals played seven instruments (clarinet, flute, French horn, saxophone, trombone, trumpet, and tuba). Two types of tests were conducted for each instrument: 10 min of playing and 10 min of combined playing and talking to mimic the teaching session. The results show that singing increased aerosol concentration to 3.9 × 103 cm-3 at the performing point, more than double the background (1.2 × 103 cm-3). Most wind instruments had minimal but detectable emission of aerosols over time, suggesting instruments could provide wall deposition for aerosols compared to singing. Particle concentrations decreased further from the performing point; however, they were still detectable over the background level at 10 feet away. Use of a portable high-efficiency particulate air (HEPA) filtration reduced aerosol concentrations developed during musical performances to below background level. These findings suggest that there are risks associated with aerosolized transmission of infectious agents such as SARS-CoV-2 from musical performance if the performer is infected. Distancing beyond the 6 ft distancing recommendation and proper room and local ventilation combined with disinfecting procedures are needed to minimize the risk of exposure to infectious aerosols.

Research on Dynamic Outpatient Respiratory Nosocomial Infection Control Methods Through Multi-Data Prediction

Objective

This study aimed to develop a dynamic prevention and control method for fluctuating respiratory nosocomial infections in outpatients.

Methods

Six sets of surveillance data such as influenza-like case counts and their predicted results were used in the autoregressive integrated moving average model (ARIMA) to forecast the onset and end time points of the epidemic peak. A Delphi process was then used to build consensus on hierarchical infection control measures for epidemic peaks and plateaus. The data, predicted results, and hierarchical infection control measures can assist dynamic prevention and control of respiratory nosocomial infections with changes in the infection risk.

Results

The ARIMA model produced exact estimates. The mean absolute percentage errors (MAPE) of the data selected to estimate the time range of the high-risk and low-risk periods were 15.8%, 9.2%, 15.4%, 16.8%, 25.6%. The hierarchical infection control measures included three categories and nine key points. A risk-period judgment matrix was also designed to connect the surveillance data and the hierarchical infection control measures.

Conclusion

Through a mathematical model, dynamic prevention and control of respiratory tract infections in outpatients was constructed based on the daily medical service monitoring data of hospitals. It is foreseeable that when applied in medical institutions, this method will provide accurate and low-cost infection prevention and control outcomes.

Using Internet of Things to Deal with Pandemic: A Use Case Based Framework

OBJECTIVE

The objective of this study is to develop a conceptual framework for use cases applicable to the development of an Internet of Things (IoT) system, designed for intelligent environments capable of managing the pandemic.

METHODS

To achieve this objective, a comprehensive content analysis of scholarly articles from MDPI, PubMed, and Google Scholar was conducted. Best practices were identified, and various application examples were synthesized to establish an IoT-based framework.

RESULTS

The study proposes measures for the implementation of technologically advanced environments and services while ensuring public compliance with these developments. Based on the identified use cases and enabled applications, a conceptual framework was formulated. The key use cases for IoT applications include traffic management, patient health monitoring, early virus detection, remote work facilitation, smart hygiene solutions, tracking infected individuals, monitoring social distancing, enhancing health care facilities, and ensuring quarantine compliance. To ensure rapid and effective implementation of policies, regulations, and government orders, robust architecture, applications, and technological infrastructures must be developed.

CONCLUSIONS

This study explores new architectural frameworks, potential use cases, and avenues for future advancements in IoT-based applications. The use cases are categorized as near-field measures, hybrid measures, centralized control mechanisms, and their integration in the defense against COVID-19.

SARS-CoV-2: The Interplay Between Evolution and Host Immunity

The persistence of SARS-CoV-2 infections at a global level reflects the repeated emergence of variant strains encoding unique constellations of mutations. These variants have been generated principally because of a dynamic host immune landscape, the countermeasures deployed to combat disease, and selection for enhanced infection of the upper airway and respiratory transmission. The resulting viral diversity creates a challenge for vaccination efforts to maintain efficacy, especially regarding humoral aspects of protection. Here, we review our understanding of how SARS-CoV-2 has evolved during the pandemic, the immune mechanisms that confer protection, and the impact viral evolution has had on transmissibility and adaptive immunity elicited by natural infection and/or vaccination. Evidence suggests that SARS-CoV-2 evolution initially selected variants with increased transmissibility but currently is driven by immune escape. The virus likely will continue to drift to maintain fitness until countermeasures capable of disrupting transmission cycles become widely available.

Mortality Among Dental Healthcare Workers During the Coronavirus Disease 2019 Pandemic: A Public Domain Database Study

BACKGROUND

This study was conducted to assess the effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on dental healthcare workers (DHCWs) during the pandemic. Due to frequent exposure to aerosol-generating procedures, DHCWs are at an increased risk of a SARS-CoV-2 infection, increasing their mortality risk. Therefore, this retrospective study aimed to ascertain the mortality of DHCWs attributable to SARS-CoV-2 infection from databases in the public domain during the pandemic.

METHODS

The data were obtained from three public-domain online databases: Medscape, FNOMCeO, and X. All collected data from March 2020 to May 2024 were merged into a tabulated format. An analysis was conducted on the data collectively and through a subgroup analysis based on the country, detailed profession, age, gender, and date of death.

RESULTS

During the SARS-CoV-2 pandemic, 100 DHCWs were deceased. The DHCWs in the study were employed in 14 countries, with the United States (40%) and Italy (34%) listing the highest percentages of deaths of these workers. Dentists constituted 79% of the total DHCWs. The gender distribution among the deceased was 85 (85%) men and 15 (15%) women. The age of 57 deceased DHCWs was known, resulting in a mean age of 58 years (ranging from 28 to 88). The DHCWs at ages 60 to 70 years (49%) exhibited the highest mortality rate from SARS-CoV-2. The date of death was known for 73 DHCWs, who were deceased between March 2020 and February 2023.

CONCLUSION AND CLINICAL RELEVANCE

During the global pandemic, DHCWs worked in the context of general practice. The DHCWs adhered to infection prevention protocols according to standard guidelines and incorporated new adjunctive measures, especially for the pandemic, including adopting coronavirus disease 2019 guidelines for oral healthcare. These measures provided satisfactory protection, with less than 0.006% mortality of the estimated DHCWs worldwide.

CO2 and aerosol concentration during manual and mechanical chest compression while cardiopulmonary resuscitation

BACKGROUND

This study investigates the staff-to-staff transmission risk of Coronavirus disease 2019 during cardiopulmonary resuscitation in an ambulance vehicle.

METHODS

Comparing manual and mechanical chest compressions, CO2 concentrations were monitored as a proxy for infection risk.

RESULTS

Results suggest that mechanical chest compressions generate lower CO2 levels, indicating a reduced risk of infection among healthcare workers compared to manual compressions.

CONCLUSIONS

These findings highlight the potential benefits of employing mechanical chest compressions to mitigate staff-to-staff infections in small, confined spaces during aerosol-transmitted diseases.

Investigation of ritonavir analogs antiretroviral natural compounds against SARS-CoV-2 envelope protein

Since the pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) was first reported from Wuhan, China, there has been a surge in scientific research to find a permanent cure for the disease. The main challenge in effective drug discovery is the continuously mutating nature of the SARS-CoV-2 virus. Thus, we have used the I-TASSER modeling to predict the structure of the SARS-CoV-2 viral envelope protein followed by combinatorial computational assessment to predict its putative potential small molecule inhibitors. As early treatment with ritonavir in combination was associated with faster time to clinical improvement and/or virological clearance, we aimed to retrieve analogs of ritonavir to find ideal inhibitors for SARS-CoV-2 viral envelope protein. The collected ligands were screened against the predicted binding pocket of viral envelope protein using extra precision (XP) docking protocol and the first four best-docked compounds were studied for complex stability using 300 ns all-atom molecular dynamics simulations embedding within the cellular membrane. Among the selected compounds, ZINC64859171 and ZINC1221429 showed considerable stability and interactions by comparison to the reference compound, i.e., Ritonavir (ZINC3944422). Moreover, the post-simulation analysis suggested the considerable binding affinity and induced conformation changes in the respective docked complexes against Ritonavir. Altogether, the obtained results demonstrated the putative potential of screened ritonavir analogs, i.e., ZINC64859171, against the envelope protein of SARS-CoV-2 and can be considered for further drug development in the treatment of the COVID-19 pandemic.Communicated by Ramaswamy H. Sarma.

Monitoring of indoor air quality at a large sailing cruise ship to assess ventilation performance and disease transmission risk

Large passenger ships are characterised as enclosed and crowded indoor spaces with frequent interactions between travellers, providing conditions that facilitate disease transmission. This study aims to provide an indoor ship CO2 dataset for inferring thermal comfort, ventilation and infectious disease transmission risk evaluation. Indoor air quality (IAQ) monitoring was conducted in nine environments (three cabins, buffet, gym, bar, restaurant, pub and theatre), on board a cruise ship voyaging across the UK and EU, with the study conducted in the framework of the EU HEALTHY SAILING project. CO2 concentrations, temperature and relative humidity (RH) were simultaneously monitored to investigate thermal characteristics and effectiveness of ventilation performance. Results show a slightly higher RH of 68.2 ± 5.3 % aboard compared to ASHRAE and ISO recommended targets, with temperature recorded at 22.3 ± 1.4 °C. Generally, good IAQ (<1000 ppm) was measured with CO2 mainly varying between 400 and 1200 ppm. The estimated air change rates (ACH) and ventilation rates (VR) implied sufficient ventilation was provided in most locations, and the theatre (VR: 86 L s-1 person-1) and cabins (VR: >20 L s-1 person-1) were highly over-ventilated. Dining areas including the pub and restaurant recorded high CO2 concentrations (>2000 ppm) potentially due to higher footfall (0.6 person m-2 and 0.4 person m-2) and limited ACH (2.3 h-1 and 0.8 h-1), indicating a potential risk of infection; these areas should be prioritised for improvement. The IAQ and probability of infection indicate there is an opportunity for energy saving by lowering hotel load for the theatre and cabins and achieving the minimum acceptable VR (10 L s-1 person-1) for occupants' comfort and disease control. Our study produced a first-time dataset from a sailing cruise ship's ventilated areas and provided evidence that can inform guidelines about the optimisation of ventilation operations in large passenger ships, contributing to respiratory health, infection control and energy efficiency aboard.

Evaporation Kinetics and Final Particle Morphology of Multicomponent Salt Solution Droplets

In both nature and industry, aerosol droplets contain complex mixtures of solutes, which in many cases include multiple inorganic components. Understanding the drying kinetics of these droplets and the impact on resultant particle morphology is essential for a variety of applications including improving inhalable drugs, mitigating disease transmission, and developing more accurate climate models. However, the previous literature has only focused on the relationship between drying kinetics and particle morphology for aerosol droplets containing a single nonvolatile component. Here we investigate the drying kinetics of NaCl-(NH4)2SO4, NaCl-NH4NO3, and NaCl-CaCl2 mixed salt aqueous aerosol droplets (25-35 μm radius) and the resulting morphology and composition of the dried microparticles. A comparative kinetics electrodynamic balance was used to measure evaporation profiles for each mixed salt aerosol at a range of relative humidities (RH) (0-50% RH); measurements of the evaporation kinetics are shown to be consistent with predictions from the "Single Aerosol Drying Kinetics and Trajectories" model. Populations of the mixed salt droplets were dried in a falling droplet column under different RH conditions and imaged using scanning electron microscopy to observe the impact of the drying kinetics on the morphology. Energy dispersive spectroscopy was used in tandem to obtain atomic maps and view the impact of drying kinetics on the composition of the resultant particles. It has been shown that the relationship between drying kinetics and dry particle morphology in mixed salt solution droplets is compositionally dependent and determined by the predominant salts that crystallize (i.e., (NH4)2SO4, Na2SO4, or NaCl). The degree of homogeneity in composition throughout the particle microstructure is dependent on the drying rate.

Comparative Analysis of Virology and Pathogenesis of SARS-CoV-2 and HIV Infections: Implications for Public Health and Treatment Strategies

Introduction

Coronavirus Disease 19 (COVID-19), caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), and Human Immunodeficiency Virus (HIV) are significant 21st-century pandemics with distinct virological and clinical characteristics. COVID-19 primarily presents as an acute respiratory illness, while HIV leads to chronic immune suppression. Understanding their differences can enhance public health strategies and treatment approaches.

Purpose

This narrative review compares the virology, transmission, immune responses, and clinical outcomes of SARS-CoV-2 and HIV to inform treatment strategies and public health interventions.

Methods

A narrative review was conducted, synthesizing data from peer-reviewed literature and expert commentary from 2010 to 2024. Databases such as PubMed, Cochrane Library, and Google Scholar were searched for relevant studies.

Results

SARS-CoV-2 primarily spreads through airborne droplets and contaminated surfaces, while HIV transmits through direct contact with infected bodily fluids. The immune response to SARS-CoV-2 involves both innate and adaptive systems, potentially leading to a cytokine storm in severe cases. In contrast, HIV evades the immune system by integrating into host cells, resulting in chronic infection and progressive immune deterioration. Treatment for SARS-CoV-2 focuses on symptom management and prevention, with antiviral medications and vaccines playing crucial roles. Conversely, HIV treatment relies on antiretroviral therapy (ART) to suppress viral replication and maintain immune function.

Conclusion

The review highlights the acute nature of SARS-CoV-2 versus the chronic progression of HIV. Tailored prevention and treatment strategies are essential for effective disease management.

Recommendations

Public health strategies should address the unique transmission routes and progression of both viruses. Further research into vaccine development and therapeutic interventions is critical for improving disease management.

Leveraging artificial intelligence to promote COVID-19 appropriate behaviour in a healthcare institution from north India: A feasibility study

Background & Objectives Non-pharmacological interventions (NPI) were crucial in curbing the initial COVID-19 pandemic waves, but compliance was difficult. The primary aim of this study was to assess the changes in compliance with NPIs in healthcare settings using Artificial intelligence (AI) and examine the barriers and facilitators of using AI systems in healthcare. Methods A pre-post-intervention study was conducted in a north-Indian hospital between April and July 2022. YOLO-V5 and 3D Cartesian distance algorithm-based AI modules were used to ascertain compliance through several parameters like confidence threshold, intersection-over-union threshold, image size, distance threshold (6 feet), and 3D Euclidean Distance estimation. Validation was done by evaluating model performance on a labelled test dataset, and accuracy was 91.3 per cent. Interventions included daily sensitization and health education for the hospital staff and visitors, display of information, education and communication (IEC) materials, and administrative surveillance. In-depth interviews were conducted with the stakeholders to assess the feasibility issues. Flagged events during the three phases were compared using One-way ANOVA tests in SPSS. Results Higher social distancing (SD) compliance events were flagged by the module in the intervention phase compared to the pre-intervention and post-intervention phases (P<0.05). Mask non-compliance was significantly lower (P <0.05) in the pre-intervention phase and highest in the post-intervention phase, with varied differences between different intervention phases in the registration hall and medicine out-patient department (OPD). The modules' data safety, transfer, and cost were the most common concerns. Interpretation & conclusions AI can supplement our efforts against the pandemic and offer indispensable help with minimal feasibility issues that can be resolved through adequate sensitization and training.

The impact of the Covid-19 pandemic on work accidents with exposure to biological material in Brazil: an interrupted time series analysis

OBJECTIVE

To analyze the impact of the Covid-19 pandemic on the occurrence of work accidents involving biological materials (ATBio) and to assess changes in the epidemiological profile of these cases.

METHODS

An ecological time-series study with a cross-sectional component was conducted using ATBio notifications in Brazil from 2015 to 2022 in the Information System for Notifiable Diseases (Sinan). Interrupted time-series analyses were performed using Prais-Winsten regression models, temporal predictions, and multiple logistic regression to identify changes in the profile between the pandemic and pre-pandemic periods.

RESULTS

A total of 499,916 ATBio cases were recorded between 2015 and 2022, with an increasing trend from 2015 to 2019. During the first year of the pandemic, 57,731 (11.5%) accidents were reported, with an estimated reduction of 791.8 ATBio notifications per month during this period. There was a change in the accident profile, with a higher occurrence of ATBio during the first year of the pandemic among workers with 1 to 8 and 9 to 11 years of education, and a lower occurrence among pregnant women. There was also a higher occurrence of exposure to non-categorized biological materials, increased use of masks and face shields, and higher post-accident seroconversion rates.

CONCLUSION

The occurrence of ATBio was impacted by the Covid-19 pandemic, leading to a reduction in notifications and a change in the event profile on a national scale.

Detection of severe acute respiratory syndrome coronavirus 2 in bioaerosols using digital droplet polymerase chain reaction and loop-mediated isothermal amplification

In the present study, we simulated human passive breathing, sampled severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) bioaerosols, and compared the detection ability of quantitative polymerase chain reaction (qPCR), digital droplet polymerase chain reaction (ddPCR), and loop-mediated isothermal amplification (LAMP). The specificity of the primer set for the LAMP-based detection of SARS-CoV-2 was evaluated, and its sensitivity using the detection threshold in the amplification curve plots was determined. Next, we used an aerosol collection environment and collected solutions containing predetermined concentrations of plasmid containing SARS-CoV-2 N gene, which were dispersed into the environment, using a cyclone sampler. Finally, we compared the ability of qPCR, ddPCR, and LAMP in detecting SARS-CoV-2 in aerosols and stock solutions. After sampling, qPCR, LAMP and ddPCR can amplify the micro viral samples exponentially. By comparing the three assays, it was judged from the results that qPCR had a slightly higher detection limit, detecting 102 copies per μL, and therefore could not be used as a test for trace samples. qPCR, LAMP, and ddPCR were able to detect aerosol samples of 101 copies per μL. LAMP was able to qualitatively detect the samples, and ddPCR was able to quantitatively detect samples of this order of magnitude. There were 23.2 that could be used as a quantitative assay. This method can be used in public places or hospitals with limited air circulation to detect aerosol-borne viruses in trace quantities and to provide a rapid early warning.

Effects of pandemic on families, parenting stress, and emotional well-being of children in villages under Mugalur Subcentre, Sarjapur PHC, Bengaluru

Introduction

The COVID-19 pandemic has not only affected the health status of the population but has also had a serious impact on family dynamics, especially in the relationship between parents and children. Home confinement along with the closures of schools has had a strong negative impact on the psychosocial wellbeing of children. This study assesses the effects of the pandemic on families, parenting stress, and emotional well-being of children in villages under Mugalur Sub-centre, Sarjapur PHC, Bengaluru.

Materials and Methods

A cross-sectional study was undertaken from January 2022 to April 2022 among parents having children in the age group of 4 to 10 years residing in villages under Mugalur Sub-center, Sarjapur PHC, Bengaluru District. The proportional allocation sampling method was followed to collect data from 210 participants using the effects of questionnaire, parent stress scale, and strength and difficulties questionnaire- parent version.

Results

Among 210 study participants, 105 (50%) were found to have moderate to high stress due to the pandemic. Parenting stress was found to be high in 40 (20%) parents and moderate in 63 (30%) parents. Assessment of the emotional well-being of children showed that 24 (11.5%) children have clinically significant problems. Significant associations were found between the effect of, parental stress and high parental stress correlated with low emotional well-being of children.

Conclusion

This study emphasizes the urgent need for targeted mental health support for families, particularly during crises such as the pandemic. Interventions aimed at reducing parental stress and promoting children's emotional well-being are crucial for mitigating adverse effects and ensuring the long-term well-being of families and communities.

Dry eye disease caused by viral infection: Past, present and future

Following viral infection, the innate immune system senses viral products, such as viral nucleic acids, to activate innate defence pathways, leading to inflammation and apoptosis, control of cell proliferation, and consequently, threat to the whole body. The ocular surface is exposed to the external environment and extremely vulnerable to viral infection. Several studies have revealed that viral infection can induce inflammation of the ocular surface and reduce tear secretion of the lacrimal gland (LG), consequently triggering ocular morphological and functional changes and resulting in dry eye disease (DED). Understanding the mechanisms of DED caused by viral infection and its potential therapeutic strategies are crucial for clinical interventional advances in DED. This review summarizes the roles of viral infection in the pathogenesis of DED, applicable diagnostic and therapeutic strategies, and potential regions of future studies.

Hospital population density and risk of respiratory infection: Is close contact density dependent?

Respiratory infections acquired in hospital depend on close contact, which may be affected by hospital population density. Models of infectious disease transmission typically assume that contact rates are independent of density (frequency dependence) or proportional to it (linear density dependence), without justification. We evaluate these assumptions by measuring contact rates in hospitals under different population densities. We analysed data from a study in 15 wards in which staff, patients and visitors carried wearable sensors which detected close contacts. We proposed a general model, non-linear density dependence, and fit this to data on several types of interactions. Finally, we projected the fitted models to predict the effect of increasing population density on epidemic risk. We identified considerable heterogeneity in density dependence between wards, even those with the same medical specialty. Interactions between all persons present usually depended little on the population density. However, increasing patient density was associated with higher rates of patient contact for staff and for other patients. Simulations suggested that a 10 % increase in patient population density would carry a markedly increased risk in many wards. This study highlights the variance in density dependent dynamics and the complexity of predicting contact rates.

Association Between Dietary Habit Changes and COVID-19 Prophylaxis During the Pandemic Among Japanese Maintenance Hemodialysis Patients

BACKGROUND

Following COVID-19, dietary habits have been altered frequently along with other societal lifestyle modifications. However, changes in the dietary habits of maintenance hemodialysis patients (MHPs) before and during COVID-19 have not been investigated.

METHODS

A total of 132 MHPs were assessed for changes in their dietary habits before and during the pandemic and their association with COVID-19 prevention. Logistic regression models were used to calculate the adjusted odds ratios (ORs) with 95% confidence intervals (CIs) for the risk of COVID-19. A multivariate logistic regression analysis was performed.

RESULTS

Approximately 27% (36 of 132) of the MHPs modified their dietary habits. Following COVID-19, the frequency of eating out decreased, and that of eating in increased significantly for dinner. However, there was no change in dietary habits for breakfast and lunch. Multivariate analysis revealed an inverse correlation between the number of eating takeout and COVID-19; that is, more eating of takeout was associated with a lower risk of contracting COVID-19.

CONCLUSIONS

Comparing before and after the pandemic, there was a shift from eating out to eating in for dinner. However, the frequency of eating takeout played a role in preventing COVID-19, suggesting that the person preparing the meal may be a more important factor than where the meal is eaten when the main route of infection is household transmission.

Microfluidics-based condensation bioaerosol sampler for multipoint airborne virus monitoring

To facilitate rapid monitoring of airborne viruses, they must be collected with high efficiency and concentrated in a small volume of a liquid sample. In addition, the development of low-cost miniaturized samplers is essential for multipoint monitoring. Thus, in an attempt to fulfill these requirements, this study developed a microfluidic condensation bioaerosol sampler (MCBS). The developed sampler comprised two parts: a virus growth section and a virus droplet-to-liquid sample conversion section, each of which was fabricated on a chip using microfluidic technology. The condensation nucleus growth technique used in the virus growth section grew nanometer-sized airborne viruses into micro-sized droplets, making it possible to collection of viruses easier and with high efficiency. In addition, the virus droplet-to-liquid sample conversion section controlled the transport of droplets based on electrowetting technology. This enabled the collected airborne viruses to be concentrated in tens of microliters of the liquid sample. To evaluate the performance of both the sections, the virus dropletization, virus collection efficiency, and virus droplet-to-liquid sample conversion efficiency were evaluated through quantitative experiments. H1N1 and HCOV-229E viruses were used to conduct quantitative experiments on MCBS. We could obtain virus liquid samples with at 72.8- and 89.9-times higher concentration through 1:1 evaluation with a commercial sampler. Thus, the developed sampler facilitated efficient collection and concentration of airborne viruses in a compact, cost-effective manner. This is expected to facilitate rapid and accurate multipoint monitoring of viral aerosols.

Antiseptics: An expeditious third force in the prevention and management of coronavirus diseases

Notably, severe acute respiratory syndrome (SARS), Middle East respiratory syndrome (MERS) and coronavirus disease 2019 (COVID-19) have all had significant negative impact on global health and economy. COVID-19 alone, has resulted to millions of deaths with new cases and mortality still being reported in its various waves. The development and use of vaccines have not stopped the transmission of SARS coronavirus 2 (SARS-CoV-2), the etiological agent of COVID-19, even among vaccinated individuals. The use of vaccines and curative drugs should be supplemented with adoption of simple hygiene preventive measures in the fight against the spread of the virus, especially for healthcare workers. Several virucidal topical antiseptics, such as povidone-iodine (PVP-I), citrox, cyclodextrins among others, have been demonstrated to be efficacious in the inactivation of SARS-CoV-2 and other coronaviruses in both in vitro and in vivo studies. The strategic application of these virucidal formulations could provide the additional impetus needed to effectively control the spread of the virus. We have here presented a simple dimension towards curtailing the dissemination of COVID-19, and other coronaviruses, through the application of effective oral, nasal and eye antiseptics among patients and medical personnel. We have further discussed the mechanism of action of some of these commonly available virucidal solutions while also highlighting some essential controversies in their use.

Aerosol particle dispersion in spontaneous breathing training of oxygen delivery tracheostomized patients on prolonged mechanical ventilation

BACKGROUND

Tracheostomized patients undergoing liberation from mechanical ventilation (MV) are exposed to the ambient environment through humidified air, potentially heightening aerosol particle dispersion. This study was designed to evaluate the patterns of aerosol dispersion during spontaneous breathing trials in such patients weaning from prolonged MV.

METHODS

Particle Number Concentrations (PNC) at varying distances from tracheostomized patients in a specialized weaning unit were quantified using low-cost particle sensors, calibrated against a Condensation Particle Counter. Different oxygen delivery methods, including T-piece and collar mask both with the humidifier or with a small volume nebulizer (SVN), and simple collar mask, were employed. The PNC at various distances and across different oxygen devices were compared using the Kruskal-Wallis test.

RESULTS

Of nine patients receiving prolonged MV, five underwent major surgery, and eight were successfully weaned from ventilation. PNCs at distances ranging from 30 cm to 300 cm showed no significant disparity (H(4) = 8.993, p = 0.061). However, significant differences in PNC were noted among oxygen delivery methods, with Bonferroni-adjusted pairwise comparisons highlighting differences between T-piece or collar mask with SVN and other devices.

CONCLUSION

Aerosol dispersion within 300 cm of the patient was not significantly different, while the nebulization significantly enhances ambient aerosol dispersion in tracheostomized patients on prolonged MV.

Reliability of YouTube videos on the management of orthodontic emergencies during COVID-19 pandemic: A quantitative and qualitative analysis

OBJECTIVES

To assess the content of YouTube videos on the management of orthodontic emergencies during the COVID-19 pandemic.

MATERIALS AND METHODS

YouTube was systematically searched using the keywords "orthodontic emergency," "orthodontic homecare," "braces emergency," and "braces homecare." The first 100 videos for each keyword were assessed. The upload source, number of views, likes and dislikes, duration, and global quality score were extracted. Home and clinical advice reliability was evaluated using the reliability score (DISCERN) according to the COVID-19 orthodontic emergencies protocol published by the British Orthodontic Society.

RESULTS

The majority of the videos were found to be poor quality. Home care advice showed higher reliability than clinical advice. Orthodontic emergency videos uploaded by healthcare professionals had higher reliability.

CONCLUSION

Many types of orthodontic emergencies have received little attention on YouTube, and more useful and reliable educational videos should be uploaded in the event of future pandemics.

Prevalence, Patterns, and Predictors of SARS-CoV-2 RNA and Culturable Virus in Tears of a Case-Ascertained Household Cohort

PURPOSE

To investigate the prevalence, patterns, and predictors of SARS-CoV-2 RNA and culturable virus in tears of a case-ascertained household cohort.

DESIGN

Prospective, longitudinal case-ascertained household cohort identified through convenience sampling.

METHODS

This analysis was restricted to individuals who were non-hospitalized, symptomatic, and tested positive for SARS-CoV-2 by nasal RT-PCR. Tears and anterior nasal biospecimens were serially collected throughout the acute period. Tears specimens were collected by the study staff using Schirmer test strips, and nasal specimens were self-collected. For both, SARS-CoV-2 RNA was quantified using qRT-PCR, and culturable virus was detected using presence of cytopathic effect (CPE) in tissue culture; positive CPE was confirmed by a qRT-PCR step. A series of cross-sectional unadjusted analyses were performed investigating the relationship between different sociodemographic determinants and biological factors associated with tears RNA positivity.

RESULTS

Among the 83 SARS-CoV-2 infected participants, 10 (12%) had at least one RNA-positive tears specimen. Amongst these 10, 5 (50%) had concurrent presence of culturable virus, at a median of 7 days postsymptom onset (IQR: 4-7 days) (absolute range: 4-8 days).

CONCLUSIONS

In this longitudinal cohort, we found evidence of culturable virus in the tears of a small proportion of nonhospitalized SARS-CoV-2 infected individuals. Current public health infection precautions do not account for transmission via tears, so these findings may improve our understanding of potential sources of SARS-CoV-2 transmission and contribute to developing future guidelines.

Exposure assessment of severe acute respiratory syndrome coronavirus 2 and norovirus genogroup I/genogroup II in aerosols generated by a municipal wastewater treatment plant

The presence of severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) in wastewater and its potential as an airborne transmission source require extensive investigation, particularly in wastewater treatment plants (WWTPs), where few studies have been conducted. The aim of this study was to investigate the presence of SARS‐CoV‐2 and norovirus (NoV) RNA in wastewater and air samples collected from a municipal WWTP. In addition, the study assessed the potential risk of viral exposure among WWTP employees. In both the summer and winter campaigns of this study, SARS‐CoV‐2 and NoV RNA were quantified in wastewater/sludge samples other than effluent. Viral RNA was not detected in any of the air samples collected. The exposure risk assessment with the SARS‐CoV‐2 RNA concentrations in the influent pumping station of this study shows a lower risk than the calculation with the historical data provided by AquaVall, but both show a low‐to‐medium exposure risk for the WWTP workers. The sensitivity analysis shows that the result of the model is strongly influenced by the SARS‐CoV‐2 RNA quantification in the wastewater. This study underscores the need for extensive investigations into the presence and viability of SARS‐CoV‐2 in wastewater, especially as a potential airborne transmission source within WWTPs.

3-chymotrypsin-like protease in SARS-CoV-2

Coronaviruses constitute a significant threat to the human population. Severe acute respiratory syndrome coronavirus-2, SARS-CoV-2, is a highly pathogenic human coronavirus that has caused the coronavirus disease 2019 (COVID-19) pandemic. It has led to a global viral outbreak with an exceptional spread and a high death toll, highlighting the need for effective antiviral strategies. 3-Chymotrypsin-like protease (3CLpro), the main protease in SARS-CoV-2, plays an indispensable role in the SARS-CoV-2 viral life cycle by cleaving the viral polyprotein to produce 11 individual non-structural proteins necessary for viral replication. 3CLpro is one of two proteases that function to produce new viral particles. It is a highly conserved cysteine protease with identical structural folds in all known human coronaviruses. Inhibitors binding with high affinity to 3CLpro will prevent the cleavage of viral polyproteins, thus impeding viral replication. Multiple strategies have been implemented to screen for inhibitors against 3CLpro, including peptide-like and small molecule inhibitors that covalently and non-covalently bind the active site, respectively. In addition, allosteric sites of 3CLpro have been identified to screen for small molecules that could make non-competitive inhibitors of 3CLpro. In essence, this review serves as a comprehensive guide to understanding the structural intricacies and functional dynamics of 3CLpro, emphasizing key findings that elucidate its role as the main protease of SARS-CoV-2. Notably, the review is a critical resource in recognizing the advancements in identifying and developing 3CLpro inhibitors as effective antiviral strategies against COVID-19, some of which are already approved for clinical use in COVID-19 patients.

CD4+ and CD8+ T cells are required to prevent SARS-CoV-2 persistence in the nasal compartment

SARS-CoV-2 infection induces the generation of virus-specific CD4+ and CD8+ effector and memory T cells. However, the contribution of T cells in controlling SARS-CoV-2 during infection is not well understood. Following infection of C57BL/6 mice, SARS-CoV-2-specific CD4+ and CD8+ T cells are recruited to the respiratory tract, and a vast proportion secrete the cytotoxic molecule granzyme B. Using depleting antibodies, we found that T cells within the lungs play a minimal role in viral control, and viral clearance occurs in the absence of both CD4+ and CD8+ T cells through 28 days postinfection. In the nasal compartment, depletion of both CD4+ and CD8+ T cells, but not individually, results in persistent, culturable virus replicating in the nasal epithelial layer through 28 days postinfection. Viral sequencing analysis revealed adapted mutations across the SARS-CoV-2 genome, including a large deletion in ORF6. Overall, our findings highlight the importance of T cells in controlling virus replication within the respiratory tract during SARS-CoV-2 infection.

Comparative study of DCNN and image processing based classification of chest X-rays for identification of COVID-19 patients using fine-tuning

The conventional detection of COVID-19 by evaluating the CT scan images is tiresome, often experiences high inter-observer variability and uncertainty issues. This work proposes the automatic detection and classification of COVID-19 by analysing the chest X-ray images (CXR) with the deep convolutional neural network (DCNN) models through a fine-tuning and pre-training approach. CXR images pertaining to four health scenarios, namely, healthy, COVID-19, bacterial pneumonia and viral pneumonia, are considered and subjected to data augmentation. Two types of input datasets are prepared; in which dataset I contains the original image dataset categorised under four classes, whereas the original CXR images are subjected to image pre-processing via Contrast Limited Adaptive Histogram Equalisation (CLAHE) algorithm and Blackhat Morphological Operation (BMO) for devising the input dataset II. Both datasets are supplied as input to various DCNN models such as DenseNet, MobileNet, ResNet, VGG16, and Xception for achieving multi-class classification. It is observed that the classification accuracies are improved, and the classification errors are reduced with the image pre-processing. Overall, the VGG16 model resulted in better classification accuracies and reduced classification errors while accomplishing multi-class classification. Thus, the proposed work would assist the clinical diagnosis, and reduce the workload of the front-line healthcare workforce and medical professionals.

Scientific uncertainty and the challenges of applying criminal law: Lessons from China's COVID-19 response

This study addresses the complexities of applying criminal law during public health emergencies, particularly under the shadow of scientific uncertainty, and explores the challenge of balancing public health protection with individual rights. The primary aim is to dissect the application of criminal law in the context of the COVID-19 pandemic in China, focusing on the impact of scientific uncertainty on legal decision-making and the efficacy of criminal law interventions in public health crises. This study utilized a doctrinal method combined with case studies, integrating theoretical frameworks on risk and uncertainty with an analysis of China's legal responses to COVID-19. It involved assessing legislative and policy documents alongside judicial decisions, focusing on their alignment with evolving scientific understanding and public health strategies. The study reveals significant hurdles, including the limitations of empirical rules in judicial judgments, the emergence of technocratic bureaucracy, and the complexities surrounding risk mitigation and legal attribution under uncertain conditions. It highlights the inadequacy of traditional criminal law mechanisms to respond dynamically to the evolving landscape of public health emergencies. To address these challenges, the study recommends the development of temporary criminal legislation tailored to public health emergencies, the adoption of risk-based criminal law approaches, and the refinement of individualized risk assessment procedures. These measures aim to provide a more flexible and effective legal framework capable of safeguarding public health while ensuring the protection of individual liberties during crises.

Comprehensive Review of COVID-19: Epidemiology, Pathogenesis, Advancement in Diagnostic and Detection Techniques, and Post-Pandemic Treatment Strategies

At present, COVID-19 remains a public health concern due to the ongoing evolution of SARS-CoV-2 and its prevalence in particular countries. This paper provides an updated overview of the epidemiology and pathogenesis of COVID-19, with a focus on the emergence of SARS-CoV-2 variants and the phenomenon known as 'long COVID'. Meanwhile, diagnostic and detection advances will be mentioned. Though many inventions have been made to combat the COVID-19 pandemic, some outstanding ones include multiplex RT-PCR, which can be used for accurate diagnosis of SARS-CoV-2 infection. ELISA-based antigen tests also appear to be potential diagnostic tools to be available in the future. This paper also discusses current treatments, vaccination strategies, as well as emerging cell-based therapies for SARS-CoV-2 infection. The ongoing evolution of SARS-CoV-2 underscores the necessity for us to continuously update scientific understanding and treatments for it.

Impact of nebulization versus metered-dose inhaler utilization on viral particle dispersion in patients with COVID-19

Background

Conflicting guidance exists regarding the characterization of nebulization as an aerosol-generating procedure and subsequent risk of transmission of SARS-CoV-2 to healthcare workers.

Aim/Objective

This study sought to address whether SARS-CoV-2 viral load distribution was impacted by bronchodilator delivery via nebulizer versus metered-dose inhaler (MDI).

Methods

Adults infected with COVID-19 were enrolled and received a single dose of albuterol sulfate nebulized solution (2.5 mg/3 mL via breath-actuated nebulizer with filtered mouthpiece) or albuterol sulfate hydrofluoroalkane inhalation aerosol (90 µg/actuation; two puffs via MDI with spacer) in a randomized crossover sequence. Air and surfaces were sampled at predefined locations within patients' hospital rooms to assess SARS-CoV-2 dispersion over three periods (baseline, MDI, and nebulizer).

Findings/Results

Eleven patients received crossover therapy. Six patients had detectable SARS-CoV-2 RNA during one treatment period (n = 3 each for MDI and nebulizer) and one during both treatment periods. No viral RNA was found in the rooms of four (36.4%) patients. Overall, few environmental samples (17/397; 4.3%) contained detectable viral RNA, with no meaningful differences in positivity rate across periods; RNA genome copy numbers were low in positive samples. No correlation between dispersion and patient clinical status or environmental parameters was observed.

Discussion

In this first prospective trial evaluating viral load distribution following use of nebulizer versus MDI in hospitalized patients with COVID-19, low environmental contamination was found regardless of administration method. Findings support the use of either device when needed to treat patients with COVID-19.

Association between Health Literacy and Self-care Behaviors with Traditional Thai Medicine during the COVID-19 Pandemic

Background

Health literacy is a multidimensional concept that can lead to changing self-care behaviors.

Objective

This study aimed to assess health literacy, self-care behaviors, and factors related to self-care behaviors in traditional Thai medicine during the COVID-19 pandemic.

Methods

This cross-sectional study included 422 participants. The questionnaire consisted of sociodemographic characteristics, health literacy of traditional Thai medicine with COVID-19, and self-care behavior with traditional Thai medicine in relation to COVID-19. The data were analyzed using descriptive statistics, independent-sample test, one-way ANOVA, and Pearson's correlation coefficient.

Results

The mean score for communication to promote health was high (34.6±8.4). The mean score of overall health literacy was moderate (156.8±20.7), followed by self-care behavior (45.6±6.0), access to health information and services (30.5±5.2), and health knowledge and understanding (26.7±2.6). Pearson correlation coefficient analysis showed that there were significantly positive self-care behaviors, namely, access to health information and services (P-value < 0.001), communication to promote health (P-value < 0.001), media and information literacy (P-value < 0.043), and overall health literacy (P-value < 0.003), while informed decision-making was significantly negatively associated with self-care behaviors (P-value < 0.004).

Conclusion

Increasing overall health literacy and each dimension was associated with self-care behaviors. The findings suggest that interventional programs to develop health literacy are required to improve self-care behaviors.

Weak Value Amplification Based Optical Sensor for High Throughput Real-Time Immunoassay of SARS-CoV-2 Spike Protein

The demand for accurate and efficient immunoassays calls for the development of precise, high-throughput analysis methods. This paper introduces a novel approach utilizing a weak measurement interface sensor for immunoassays, offering a solution for high throughput analysis. Weak measurement is a precise quantum measurement method that amplifies the weak value of a system in the weak interaction through appropriate pre- and post-selection states. To facilitate the simultaneous analysis of multiple samples, we have developed a chip with six flow channels capable of conducting six immunoassays concurrently. We can perform real-time immunoassay to determine the binding characteristics of spike protein and antibody through real-time analysis of the flow channel images and calculating the relative intensity. The proposed method boasts a simple structure, eliminating the need for intricate nano processes. The spike protein concentration and relative intensity curve were fitted using the Log-Log fitting regression equation, and R2 was 0.91. Utilizing a pre-transformation approach to account for slight variations in detection sensitivity across different flow channels, the present method achieves an impressive limit of detection(LOD) of 0.85 ng/mL for the SARS-CoV-2 the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein, with a system standard deviation of 5.61. Furthermore, this method has been successfully verified for monitoring molecular-specific binding processes and differentiating binding capacities.

Symptom propagation in respiratory pathogens of public health concern: a review of the evidence

Symptom propagation occurs when the symptom set an individual experiences is correlated with the symptom set of the individual who infected them. Symptom propagation may dramatically affect epidemiological outcomes, potentially causing clusters of severe disease. Conversely, it could result in chains of mild infection, generating widespread immunity with minimal cost to public health. Despite accumulating evidence that symptom propagation occurs for many respiratory pathogens, the underlying mechanisms are not well understood. Here, we conducted a scoping literature review for 14 respiratory pathogens to ascertain the extent of evidence for symptom propagation by two mechanisms: dose-severity relationships and route-severity relationships. We identify considerable heterogeneity between pathogens in the relative importance of the two mechanisms, highlighting the importance of pathogen-specific investigations. For almost all pathogens, including influenza and SARS-CoV-2, we found support for at least one of the two mechanisms. For some pathogens, including influenza, we found convincing evidence that both mechanisms contribute to symptom propagation. Furthermore, infectious disease models traditionally do not include symptom propagation. We summarize the present state of modelling advancements to address the methodological gap. We then investigate a simplified disease outbreak scenario, finding that under strong symptom propagation, isolating mildly infected individuals can have negative epidemiological implications.

In Silico Comparative Analysis of Ivermectin and Nirmatrelvir Inhibitors Interacting with the SARS-CoV-2 Main Protease

Exploring therapeutic options is crucial in the ongoing COVID-19 pandemic caused by SARS-CoV-2. Nirmatrelvir, which is a potent inhibitor that targets the SARS-CoV-2 Mpro, shows promise as an antiviral treatment. Additionally, Ivermectin, which is a broad-spectrum antiparasitic drug, has demonstrated effectiveness against the virus in laboratory settings. However, its clinical implications are still debated. Using computational methods, such as molecular docking and 100 ns molecular dynamics simulations, we investigated how Nirmatrelvir and Ivermectin interacted with SARS-CoV-2 Mpro(A). Calculations using density functional theory were instrumental in elucidating the behavior of isolated molecules, primarily by analyzing the frontier molecular orbitals. Our analysis revealed distinct binding patterns: Nirmatrelvir formed strong interactions with amino acids, like MET49, MET165, HIS41, HIS163, HIS164, PHE140, CYS145, GLU166, and ASN142, showing stable binding, with a root-mean-square deviation (RMSD) of around 2.0 Å. On the other hand, Ivermectin interacted with THR237, THR239, LEU271, LEU272, and LEU287, displaying an RMSD of 1.87 Å, indicating enduring interactions. Both ligands stabilized Mpro(A), with Ivermectin showing stability and persistent interactions despite forming fewer hydrogen bonds. These findings offer detailed insights into how Nirmatrelvir and Ivermectin bind to the SARS-CoV-2 main protease, providing valuable information for potential therapeutic strategies against COVID-19.

COVID-19: Post infection implications in different age groups, mechanism, diagnosis, effective prevention, treatment, and recommendations

SARS-CoV-2 is a highly contagious pathogen that predominantly caused the COVID-19 pandemic. The persistent effects of COVID-19 are defined as an inflammatory or host response to the virus that begins four weeks after initial infection and persists for an undetermined length of time. Chronic effects are more harmful than acute ones thus, this review explored the long-term effects of the virus on various human organs, including the pulmonary, cardiovascular, and neurological, reproductive, gastrointestinal, musculoskeletal, endocrine, and lymphoid systems and found that SARS-CoV-2 adversely affects these organs of older adults. Regarding diagnosis, the RT-PCR is a gold standard method of diagnosing COVID-19; however, it requires specialized equipment and personnel for performing assays and a long time for results production. Therefore, to overcome these limitations, artificial intelligence employed in imaging and microfluidics technologies is the most promising in diagnosing COVID-19. Pharmacological and non-pharmacological strategies are the most effective treatment for reducing the persistent impacts of COVID-19 by providing immunity to post-COVID-19 patients by reducing cytokine release syndrome, improving the T cell response, and increasing the circulation of activated natural killer and CD8 T cells in blood and tissues, which ultimately reduces fever, nausea, fatigue, and muscle weakness and pain. Vaccines such as inactivated viral, live attenuated viral, protein subunit, viral vectored, mRNA, DNA, or nanoparticle vaccines significantly reduce the adverse long-term virus effects in post-COVID-19 patients; however, no vaccine was reported to provide lifetime protection against COVID-19; consequently, protective measures such as physical separation, mask use, and hand cleansing are promising strategies. This review provides a comprehensive knowledge of the persistent effects of COVID-19 on people of varying ages, as well as diagnosis, treatment, vaccination, and future preventative measures against the spread of SARS-CoV-2.

Parametric analysis of SARS-CoV-2 dose-response models in transportation scenarios

Transportation systems involve high-density crowds of geographically diverse people with variations in susceptibility; therefore, they play a large role in the spread of infectious diseases like SARS-CoV-2. Dose-response models are widely used to model the relationship between the trigger of a disease and the level of exposure in transmission scenarios. In this study, we quantified and bounded viral exposure-related parameters using empirical data from five transportation-related events of SARS-CoV-2 transmission. Dose-response models were then applied to parametrically analyze the infection spread in generic transportation systems, including a single-aisle airplane, bus, and railway coach, and then examined the mitigating efficiency of masks by performing a sensitivity analysis of the related factors. We found that dose level significantly affected the number of secondary infections. In general, we observed that mask usage reduced infection rates at all dose levels and that high-quality masks equivalent to FFP2/N95 masks are effective for all dose levels. In comparison, we found that lower-quality masks exhibit limited mitigation efficiency, especially in the presence of high dosage. The sensitivity analysis indicated that a reduction in the infection distance threshold is a critical factor in mask usage.

Pilot study in Hamburg on the prevalence of SARS-CoV-2 infections and pandemic survey in the German funeral industry

Funeral home and crematorium workers are an important occupational group in the corona crisis. The occupational setting led to concerns about an increased risk of infection with SARS-CoV-2. The seroprevalence in this occupational group is unclear. A questionnaire-based retrospective survey of funeral home and crematorium staff was conducted in December 2020. A second survey of funeral and crematorium staff was conducted 6 months later, in June 2021, to determine changes in pandemic management. Seroprevalence or vaccination status for SARS-CoV-2 was determined at these two time points. In December 2020, a seroprevalence of 2.3% (n = 1/44) was detected in funeral home and crematorium workers. In June 2021, one additional participant tested positive for the SARS-CoV-2 nucleocapsid. Of the participants, 48.5% (n = 16) were vaccinated at this time. The risk of SARS-CoV-2 infection for funeral home and crematorium workers is more similar to that of the general population in Hamburg, Germany. We found no evidence of an increased risk of infection at these two time points in our cohort. Further education on communicable diseases or appropriate protective measures in this occupational group for other infectious diseases would be useful in the future.

Evaluation of self-collected nasal, urine, and saliva samples for molecular detection of SARS-CoV-2 using an EUA approved RT-PCR assay and a laboratory developed LAMP SARS-CoV-2 test

As the SARS-CoV-2 virus spread throughout the world, millions of positive cases of COVID-19 were registered and, even though there are millions of people already vaccinated against SARS-CoV-2, a large part of the global population remains vulnerable to contracting the virus. Massive nasopharyngeal sample collection in Puerto Rico at the beginning of the pandemic was limited by the scarcity of trained personnel and testing sites. To increase SARS-CoV-2 molecular testing availability, we evaluated the diagnostic accuracy of self-collected nasal, saliva, and urine samples using the TaqPath reverse transcription polymerase chain reaction (RT-PCR) COVID-19 kit to detect SARS-CoV-2. We also created a colorimetric loop-mediated isothermal amplification (LAMP) laboratory developed test (LDT) to detect SARS-CoV-2, as another strategy to increase the availability of molecular testing in community-based laboratories. Automated RNA extraction was performed in the KingFisher Flex instrument, followed by PCR quantification of SARS-CoV-2 on the 7500 Fast Dx RT-PCR using the TaqPath RT-PCR COVID-19 molecular test. Data was interpreted by the COVID-19 Interpretive Software from Applied Biosystems and statistically analyzed with Cohen's kappa coefficient (k). Cohen's kappa coefficient (k) for paired nasal and saliva samples showed moderate agreement (0.52). Saliva samples exhibited a higher viral load. We also observed 90% concordance between LifeGene-Biomarks' SARS-CoV-2 Rapid Colorimetric LAMP LDT and the TaqPath RT-PCR COVID-19 test. Our results suggest that self-collected saliva is superior to nasal and urine samples for COVID-19 testing. The results also suggest that the colorimetric LAMP LDT is a rapid alternative to RT-PCR tests for the detection of SARS-CoV-2. This test can be easily implemented in clinics, hospitals, the workplace, and at home; optimizing the surveillance and collection process, which helps mitigate global public health and socioeconomic upheaval caused by airborne pandemics.

Public views on tourist beach environment from multinational countries and ensuing changes during global epidemic

The continuous endemic of the new SARS-CoV-2 virus brought a halt to the world's activities from February 2020. Our study intends to gauge public perceptions on the consequences of post-pandemic changes on the marine environment, particularly as they are related to tourist beach amenities. Totally, 16 nations' knowledge and views on various environmental viewpoints over the effects of epidemic were gathered through public polls live on social media during social confinement in 2020. The results indicate that around 85% of respondents were most concerned about the alarming sights of widespread plastic trash and the increase of dangerous biomedical wastes through wastewater in the marine ecosystem. The outcomes of this study will undoubtedly aid in the establishment of a management strategy and for future studies on the consequences of any epidemic on the beaches.

A COVID-19 cluster analysis in an office: Assessing the long-range aerosol and fomite transmissions with infection control measures

Simulated exposure to severe acute respiratory syndrome coronavirus 2 in the environment was demonstrated based on the actual coronavirus disease 2019 cluster occurrence in an office, with a projected risk considering the likely transmission pathways via aerosols and fomites. A total of 35/85 occupants were infected, with the attack rate in the first stage as 0.30. It was inferred that the aerosol transmission at long-range produced the cluster at virus concentration in the saliva of the infected cases on the basis of the simulation, more than 108 PFU mL-1. Additionally, all wearing masks effectiveness was estimated to be 61%-81% and 88%-95% reduction in risk for long-range aerosol transmission in the normal and fit state of the masks, respectively, and a 99.8% or above decline in risk of fomite transmission. The ventilation effectiveness for long-range aerosol transmission was also calculated to be 12%-29% and 36%-66% reductions with increases from one air change per hour (ACH) to two ACH and six ACH, respectively. Furthermore, the virus concentration reduction in the saliva to 1/3 corresponded to the risk reduction for long-range aerosol transmission by 60%-64% and 40%-51% with and without masks, respectively.

Cost-effectiveness analysis of surgical masks, N95 masks compared to wearing no mask for the prevention of COVID-19 among health care workers: Evidence from the public health care setting in India

BACKGROUND

Nonpharmacological interventions, such as personal protective equipment for example, surgical masks and respirators, and maintenance of hand hygiene along with COVID-19 vaccines have been recommended to reduce viral transmission in the community and health care settings. There is evidence from the literature that surgical and N95 masks may reduce the initial degree of exposure to the virus. A limited research that has studied the cost-effective analysis of surgical masks and N95 masks among health care workers in the prevention of COVID-19 in India. The objective of this study was to estimate the cost-effectiveness of N95 and surgical mask compared to wearing no mask in public hospital settings for preventing COVID-19 infection among Health care workers (HCWs) from the health care provider's perspective.

METHODS

A deterministic baseline model, without any mask use, based on Eikenberry et al was used to form the foundation for parameter estimation and to estimate transmission rates among HCWs. Information on mask efficacy, including the overall filtering efficiency of a mask and clinical efficiency, in terms of either inward efficiency(ei) or outward efficiency(e0), was obtained from published literature. Hospitalized HCWs were assumed to be in one of the disease states i.e., mild, moderate, severe, or critical. A total of 10,000 HCWs was considered as representative of the size of a tertiary care institution HCW population. The utility values for the mild, moderate and severe model health states were sourced from the primary data collection on quality-of-life of HCWs COVID-19 survivors. The utility scores for mild, moderate, and severe COVID-19 conditions were 0.88, 0.738 and 0.58, respectively. The cost of treatment for mild sickness (6,500 INR per day), moderate sickness (10,000 INR per day), severe (require ICU facility without ventilation, 15,000 INR per day), and critical (require ICU facility with ventilation per day, 18,000 INR) per day as per government and private COVID-19 treatment costs and capping were considered. One way sensitivity analyses were performed to identify the model inputs which had the largest impact on model results.

RESULTS

The use of N95 masks compared to using no mask is cost-saving of $1,454,632 (INR 0.106 billion) per 10,000 HCWs in a year. The use of N95 masks compared to using surgical masks is cost-saving of $63,919 (INR 0.005 billion) per 10,000 HCWs in a year. the use of surgical masks compared to using no mask is cost-saving of $1,390,713 (INR 0.102 billion) per 10,000 HCWs in a year. The uncertainty analysis showed that considering fixed transmission rate (1.7), adoption of mask efficiency as 20%, 50% and 80% reduces the cumulative relative mortality to 41%, 79% and 94% respectively. On considering ei = e0 (99%) for N95 and surgical mask with ei = e0 (90%) the cumulative relative mortality was reduced by 97% and the use of N95 masks compared to using surgical masks is cost-saving of $24,361 (INR 0.002 billion) per 10,000 HCWs in a year.

DISCUSSION

Both considered interventions were dominant compared to no mask based on the model estimates. N95 masks were also dominant compared to surgical masks.

Human emissions of size-resolved fluorescent bioaerosols in control situations

Human bioaerosols contribute significantly to indoor air quality. This study used a Wideband Integrated Bioaerosol Sensor (WIBS-4A) instrument for real-time measurement of particle size distribution and count to differentiate fluorescent bioaerosols from non-fluorescent aerosols. Through an experiment involving 12 subjects (six men and six women) wearing standard cotton clothing in a 2 m × 2 m × 2 m environmental chamber, we established a quantitative method to obtain the bioaerosol emission rate of a single subject, aiming to explore the effects of masks and sex on bioaerosol emissions from different individuals. The mean emission rates of fluorescent bioaerosols in the particle size ranges of 0.5-2.5 μm and 2.5-10 μm were 3.192±2.11×104 counts/(person·h) and 13.98±9.34×104 counts/(person·h), respectively. A comparison between those wearing and not wearing masks revealed no significant differences in the emissions of fluorescent bioaerosols. This suggests respiratory sources may not significantly impact the emissions of fluorescent bioaerosols from individuals under seated breathing conditions. Significant disparities in the fluorescent bioaerosol emission rates of different biological sexes were observed through independent sample analysis. Males exhibited 41 % and 15 % higher emission rates than females for particle size ranges of 0.5-2.5 μm and 2.5-10 μm, respectively, possibly because of different metabolic rates. A significant correlation between metabolic rates and fluorescent bioaerosols (sig = 0.044 < 0.05) was observed in all the subjects. These findings underscore the individual variations that affect bioaerosol emission rates. The data provided by this study will facilitate further analysis of the on-site measured data and source analysis.

Re-inventing protection in a post-pandemic world: A new aerodynamic endonasal filtration technology

Is there a "missing device" for respiratory personal protection? Does it exist an easy-to-use device, allowing extensive use in everyday settings by the population, maximizing tolerability and low visual and physical invasiveness protecting from a wide range of threats including airborne pathogens, hence including the particle range of fine and ultrafine particles? Looking at the recent past, in the urgency of finding ready-to-use solutions for the respiratory protection of the population during the outbreak of the SARS-CoV-2 pandemic, devices for occupational safety have been used, such as filtering face masks. These are devices intended for workers operating during work shifts in environments characterized by potential high risk, known a priori, often directly sensible; this makes wearers motivated to tolerate discomfort for a given period to face a localized risk, and safety managers determined to supervise compliance with usage specifications. Their use by general population has implied known shortcomings, such as weak compatibility with relational work and activities, low tolerability during prolonged use, low compliance with the proper use of the device, all of this lessening actual protection. The need for a new perspective has emerged, targeting effectiveness in whole daily life, rather than punctual efficacy. Nasal filters are promising candidates to protect individuals throughout the day during the most varied activities, but they lack a systematic definition as a device and as a product; it follows that the high complexity needed to reach an effective performance envelop is generally underestimated. By reviewing available literature, the present paper draws on the experience from the pandemic and infers systematic product specifications and characterization methods for a new, effective personal respiratory protection device; these specifications are compared with the stringent constraints associated with the endonasal applications and, based on air filtration state of the art, quantifies the need for technology disruption and outlining possible new development paths.

Rain, rain, go away, come again another day: do climate variations enhance the spread of COVID-19?

The spread of infectious diseases was further promoted due to busy cities, increased travel, and climate change, which led to outbreaks, epidemics, and even pandemics. The world experienced the severity of the 125 nm virus called the coronavirus disease 2019 (COVID-19), a pandemic declared by the World Health Organization (WHO) in 2019. Many investigations revealed a strong correlation between humidity and temperature relative to the kinetics of the virus's spread into the hosts. This study aimed to solve the riddle of the correlation between environmental factors and COVID-19 by applying RepOrting standards for Systematic Evidence Syntheses (ROSES) with the designed research question. Five temperature and humidity-related themes were deduced via the review processes, namely 1) The link between solar activity and pandemic outbreaks, 2) Regional area, 3) Climate and weather, 4) Relationship between temperature and humidity, and 5) the Governmental disinfection actions and guidelines. A significant relationship between solar activities and pandemic outbreaks was reported throughout the review of past studies. The grand solar minima (1450-1830) and solar minima (1975-2020) coincided with the global pandemic. Meanwhile, the cooler, lower humidity, and low wind movement environment reported higher severity of cases. Moreover, COVID-19 confirmed cases and death cases were higher in countries located within the Northern Hemisphere. The Blackbox of COVID-19 was revealed through the work conducted in this paper that the virus thrives in cooler and low-humidity environments, with emphasis on potential treatments and government measures relative to temperature and humidity. HIGHLIGHTS: • The coronavirus disease 2019 (COIVD-19) is spreading faster in low temperatures and humid area. • Weather and climate serve as environmental drivers in propagating COVID-19. • Solar radiation influences the spreading of COVID-19. • The correlation between weather and population as the factor in spreading of COVID-19.

A Comprehensive Update of Anti-COVID-19 Activity of Heterocyclic Compounds

The Coronavirus disease 2019 (COVID-19) pandemic is one of the most considerable health problems across the world. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the major causative agent of COVID-19. The severe symptoms of this deadly disease include shortness of breath, fever, cough, loss of smell, and a broad spectrum of other health issues such as diarrhea, pneumonia, bronchitis, septic shock, and multiple organ failure. Currently, there are no medications available for coronavirus patients, except symptom-relieving drugs. Therefore, SARS-CoV-2 requires the development of effective drugs and specific treatments. Heterocycles are important constituents of more than 85% of the physiologically active pharmaceutical drugs on the market now. Several FDA-approved drugs have been reported including molnupiravir, remdesivir, ritonavir, oseltamivir, favipiravir, chloroquine, and hydroxychloroquine for the cure of COVID-19. In this study, we discuss potent anti-SARS-CoV-2 heterocyclic compounds that have been synthesized over the past few years. These compounds included; indole, piperidine, pyrazine, pyrimidine, pyrrole, piperazine, quinazoline, oxazole, quinoline, isoxazole, thiazole, quinoxaline, pyrazole, azafluorene, imidazole, thiadiazole, triazole, coumarin, chromene, and benzodioxole. Both in vitro and in silico studies were performed to determine the potential of these heterocyclic compounds in the fight against various SARS-CoV-2 proteins.

Quantitative evaluation of the impact of indoor relative humidity on deposition of aerosols generated during tooth grinding in a real-world clinical setting

OBJECTIVES

Exposure to aerosol particles generated from tooth grinding has a negative impact on the health of dental personnel. The aim of this study was to quantitatively analyze the impact of indoor relative humidity (IRH) on the deposition of these suspended particles in a well-controlled dental environment.

MATERIALS AND METHODS

In this study, a humidity control system was employed to effectively regulate and maintain indoor relative humidity (IRH). A novel computer-assisted numerical control system was developed to pre-treat the molar specimens, and accurately simulate clinical tooth grinding procedures. Each procedure was performed in triplicate, with an online real-time particle counter (ORPC; TR-8301, TongrenCo.) measuring aerosol production. All testing devices were controlled remotely. The data obtained were statistically analyzed using descriptive statistics and non-parametric tests (Kruskal-Wallis/ Dunn's post hoc test with Bonferroni correction, p < 0.05).

RESULTS

The findings showed that with increasing IRH, the maximum peak concentration of aerosol particles decreased by 397% from 6.51 × 107 particles/m3 at 30% to 1.64 × 107 particles/m3 at 80%. The Kruskal-Wallis test results indicated a statistically significant effect of IRH on the aerosol increment (p < 0.05).

CONCLUSIONS

Increasing the IRH level can effectively promote the deposition of aerosol particles, with a return to baseline within 15 min after reaching 60% or above.

CLINICAL RELEVANCE

Our study suggested that maintaining IRH above 70% during the cleaning process, allowing natural recovery to ambient humidity levels within 15 min after cleaning, and taking basic precautions, may lead to an adequate reduction in the possible health risks of aerosol contamination.