The pathogenic potential of airborne particles carrying the SARS-CoV-2 viral genome was examined by considering the size distribution of airborne particles at given distances from the respiratory zone of an infected patient after coughing or sneezing with a focus on time, temperature, and relative humidity. The results show an association between the size distribution of airborne particles, particularly PM1 and PM2.5, and the presence of viral genome in different stations affected by the distance from the respiratory zone and the passage of time. The correlation with time was strong with all the dependent factors except PM1. Also, the effect of time intervals on the median concentration of airborne PM in the range of PM7 and PM10 was significant. Accordingly, in the first 20 min after coughing, the COVID-19 patient was more likely to be exposed to PM-carrying RNA genomes of SARS-CoV-2. The other finding was that the two distances of 0.25 m to the patient's left of the respiratory zone and 1.0 m above the breathing zone showed positive results for the presence of SARS-CoV-2 in all studied time intervals. The patterns of results suggested that there was a high potential for distribution of the virus in an infected patient based on position and airflow and that the severity of infection and viral load may influence the presence of viral load in droplets when coughing. Based on the results, one can conclude that ventilation plays a key role in mitigating the risk of airborne virus transmission in indoor environments, and it has been shown that reductions in particulate concentrations occur when portable air purifiers are placed near the breathing zone. The use of personal protective equipment for the patient and healthcare personnel to minimize the distribution of virus particles in the air is recommended.

Particulate matter (PM), a ubiquitous significant component of the ambient air pollution mixture, significantly contributes to increased global risk for chronic cardiopulmonary diseases, acute hospitalizations, and deaths. One of the causes of this increased risk is because PM exposure increases the incidence and severity of respiratory infections. The respiratory system is particularly vulnerable to air pollution and its impact on infection as it is a key site for exposure both to inhaled pollutants and infectious microbes or viruses. This review examines the current understanding of how PM affects antiviral host defense responses and possible underlying mechanisms.

While numerous studies have associated adverse health outcomes with combined or sequential exposure to inhaled pollutants and viruses, defining causal relationships and mechanisms remains limited. Particularly limited, are contemporary data focuses on low- and middle-income countries, including heavily polluted regions such as Ulaanbaatar, Mongolia. This manuscript focuses on how (1) PM, serving as a carrier for viruses, enhances the transmission of viruses; (2) PM impairs immune defense to viruses; and (3) PM impacts epithelial cell functions to exacerbate viral infections. Given the significant public health hazards on PM, particularly in heavily polluted regions such as Southeast Asia, Middle East and Africa, it is critical to define specific mechanisms of PM on respiratory infection and how their impact may differ in these highly polluted regions. Ultimately, this could devise future public health measures and interventions to limit this substantial public health risk.

Effective hand hygiene, such as hand washing and hand sanitizer use, is crucial in reducing infectious disease transmission via the hands. The efficacy of hand washing has been well-documented; however, relatively less is known regarding foam-based hand sanitizer efficacy, which is considered an effective alternative to washing hands with soap and water. Hand sanitizers are recommended by both the United States Centers for Disease Control and Prevention and the World Health Organization when the hands are not visibly dirty or greasy. This study examined the efficacy of five commercially available foam hand sanitizers-four alcohol-based and one non-alcohol-based-against enveloped and non-enveloped viruses using bacteriophage phi6 (Φ6) and bacteriophage MS2 as surrogates, respectively. A cocktail of MS2 and Φ6 (8 log PFU/mL) was inoculated on the hands and exposed to 3 or 6 mL of hand sanitizer product followed by rubbing the palmar surface of the hands together for 10 s or until dry. The results showed significant log reduction among the virus surrogates (P ≤ 0.05), with Φ6 consistently showing higher susceptibility across all factors compared with MS2 with log reductions of 2.83 ± 1.98 and 0.50 ± 0.53 log reduction, respectively. Although dosing volume did not significantly impact log reduction (P = 0.31), rubbing time significantly affected bacteriophage inactivation (P ≤ 0.05). Higher log reduction was observed when hands were rubbed until dry (2.69 ± 2.06), compared with the typical 10 s rubbing time (0.65 ± 0.75). This study revealed that the efficacy of commercially available foam hand sanitizers depends on rubbing time and overall product formulation, rather than exclusively on active ingredient concentration.IMPORTANCEHuman hands are a key factor in the transmission of viral diseases, and proper hand hygiene is regarded as the gold standard against the spread of such diseases. This study examined the effectiveness of a hand hygiene technique, that is, the application of foam-based hand sanitizers, against the inactivation of enveloped and non-enveloped virus surrogates on the hands. Factors such as virus type, rubbing time, volume of product used, and product formulation can significantly influence the efficacy of hand sanitizers. To assess these effects, we tested different rubbing times and product volumes across alcohol- and non-alcohol-based, foam hand sanitizer formulations, each with varying active ingredient concentrations and inactive ingredients. The study was performed on the palmar surface of human hands to realistically simulate real-world conditions, providing valuable evidence to inform future hand sanitizer practices aimed at maximizing the reduction of infectious viral pathogens on the hands.

Conducting persistence studies of infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on environmental surfaces may require a biosafety level 3 (BSL-3) laboratory. We aimed to compare the environmental persistence of BSL-2 level human coronaviruses (229E, NL63, and OC43) and bovine coronavirus (BoCoV) with three SARS-CoV-2 variants (WA-1, Delta, and Omicron). OC43 (1.8 TCID50/mL) and BoCoV (1.0 TCID50/mL) had lower detection thresholds in cell culture assays compared to 229E (150 TCID50/mL) and NL63 (2,670 TCID50/mL) and were used for persistence tests at room temperature. Viable OC43 became undetectable (>5.2log10) after 48 hours on stainless steel and plastic coupons but exhibited extended persistence up to 72 hours on touchscreen glass coupons. In contrast, BoCoV remained viable for up to 120 hours with <1.8 log10 infectivity loss. Both OC43 and BoCoV showed a reduction of >5 log10 on vinyl coupons after 48 hours. On stainless steel coupons, the viability of all three SARS-CoV-2 variants became undetectable (>2.3 log10 reduction) after 48 hours, with minor differences in reduction levels at 24 hours, whereas on touchscreen glass coupons, the viable virus could be detected for up to 48 hours for WA-1 and Omicron and 72 hours for the Delta variant. Regardless of coupon or virus type, viral RNA titers increased <4.5 Ct values after 120 hours. Our data demonstrate distinct persistence characteristics between BoCoV and OC43, with neither fully mimicking SARS-CoV-2 variants. This variability along with the impact of surface types on viral persistence underscores the need for caution when using these viruses as surrogates for SARS-CoV-2.IMPORTANCEIn this study, we evaluated three human seasonal coronaviruses (OC43, NL63, and 229E) and one bovine coronavirus (BoCoV) as potential surrogate viruses for SARS-CoV-2. Our data suggest that among the four surrogate viruses tested, OC43 and BoCoV were the most promising candidates due to their assay sensitivity, ease of handling, and high genetic similarity to SARS-CoV-2. However, neither BoCoV nor OC43 fully mimicked the environmental persistence characteristics of SARS-CoV-2 variants highlighting the potential limitations of using surrogate viruses.

Nail-biting or onychophagia is a common phenomenon affecting children. Excessive nail biting is associated with several adverse consequences beyond mere appearance. The aim of this study is to evaluate the effect of an empowerment program based on the BASNEF model on children's knowledge, attitude, self-efficacy, and nail-biting practice.

A quasi-experimental study was conducted in the pediatric wards of Menoufia University Hospital and Benha University Hospital. A convenience sample of 135 children (6 to 18 years) was randomly assigned to the study or control group who received routine care. To effectively measure the dependent variables, four questionnaires were developed and tested for content validity, stability reliability and internal consistency. Exploratory Factor Analysis (EFA) identified the underlying factors while the findings of the Confirmatory Factor Analysis (CFA) demonstrated a satisfactory fit. The researcher developed the session objectives, learning activities and designed a booklet with relevant content. The participants of the study group were divided into sub-groups (six children and their mothers) who attended four empowerment sessions based on the BASNEF model, emphasizing (a) age-appropriate information, (b) fostering a positive attitude towards quitting nail-biting, (c) discovering the subjective norms, perceived social expectations, and influences of nail-biting behaviors, and (d) equipping children with enabling factors to quit. The comparison between the two groups was done using the Mann-Whitney (U) test, while the Wilcoxon Signed Rank test conducted for the intragroup comparison.

There was a significant improvement in knowledge about nail-biting among children in both groups and a noticeable decline in the nail-biting habits/practices among children in the study group (22.42 ± 5.69) compared to the control group (42.76 ± 6.75). The attitude scores towards nail-biting significantly improved among children in the study group compared to the control group with appositive impact on children's self-efficacy in controlling the habit (P < 0.001 for each).

The empowerment program based on the BASNEF model effectively improved children's knowledge, attitude, self-efficacy, and practice of nail biting.

Trial registration number: NCT06471153, ClinicalTrails.gov, Retrospectively registered June 18th, 2024), URL of trial registry record: https://clinicaltrials.gov/ct2/show/NCT06471153 .

The persistence and infectivity of respiratory viruses in cadavers remain poorly characterized, posing significant biosafety risks for forensic and healthcare professionals. This study systematically evaluates the post-mortem stability and transmission potential of SARS-CoV-2, influenza A virus (IAV), and respiratory syncytial virus (RSV) under varying environmental conditions, providing critical insights into viral kinetics.

To assess the post-mortem stability of SARS-CoV-2, tissue samples were collected from infected cadavers at 4℃, room temperature (RT, 20-22℃), and 37℃ over a predetermined timeframe. Viral kinetics were analyzed using quantitative assays, while histopathology and immunohistochemistry characterized tissue-specific distribution. Additionally, comparative analyses were conducted both in vitro and in cadaveric tissues to characterize the survival dynamics of IAV and RSV under identical conditions.

SARS-CoV-2 exhibited prolonged post-mortem infectivity, persisting for up to 5 days at RT and 37℃ and over 7 days at 4℃, with the highest risk of transmission occurring within the first 72hours at RT and 24hours at 37℃. In contrast, RSV remained viable for 1-2 days, while IAV persisted for only a few hours post-mortem. Viral decay rates were temperature-dependent and varied across tissues, demonstrating distinct post-mortem survival kinetics.

This study presents the first comprehensive analysis of viral persistence in cadavers, revealing prolonged SARS-CoV-2 stability compared to IAV and RSV. These findings underscore the need for enhanced post-mortem biosafety protocols to mitigate occupational exposure risks in forensic and clinical settings. By elucidating viral decay dynamics across environmental conditions, this research establishes a critical foundation for infection control strategies, informing biosafety policies for emerging respiratory pathogens.

All data are available in the main text or the supplementary materials.

Inspired by the natural defense strategies of insect wings and plant leaves, nanostructured surfaces have emerged as a promising tool in various fields, including engineering, biomedical sciences, and materials science, to combat bacterial contamination and disrupt biofilm formation. However, the development of effective antimicrobial surfaces against fungal and viral pathogens presents distinct challenges, necessitating tailored approaches. Here, we aimed to review the recent advancements of the use of nanostructured surfaces to combat microbial contamination, particularly focusing on their mechano-bactericidal and antifungal properties, as well as their potential in mitigating viral transmission. We comparatively analyzed the diverse geometries and nanoarchitectures of these surfaces and discussed their application in various biomedical contexts, such as dental and orthopedic implants, drug delivery systems, and tissue engineering. Our review highlights the importance of preventing microbial attachment and biofilm formation, especially in the context of rising antimicrobial resistance and the economic impact of biofilms. We also discussed the latest progress in materials science, particularly nanostructured surface engineering, as a promising strategy for reducing viral transmission through surfaces. Overall, our findings underscore the significance of innovative strategies to mitigate microbial attachment and surface-mediated transmission, while also emphasizing the need for further interdisciplinary research in this area to optimize antimicrobial efficacy and address emerging challenges.

Enveloped and non-enveloped virus transmission can occur via person-to-person contact and potentially through contaminated surfaces with human hands. Establishing the efficacy of hand sanitizers, including gel and foam formats, is crucial in reducing the transmission of viruses of human health concern, yet foam hand sanitizers are generally underexplored despite being widely used. Following American Society for Testing and Materials (ASTM) E1052-20, the efficacy of foam-based hand sanitizers-one non-alcohol-based hand sanitizer and four alcohol-based hand sanitizers with benzalkonium chloride and ethanol as active ingredients, respectively-were explored using bacteriophage phi6 (Φ6) as a surrogate for enveloped viruses and bacteriophage MS2 (Emesvirus zinderi) and Tulane virus (TuV) as surrogates for non-enveloped viruses. Significant differences in log reduction were observed among viruses (P ≤ 0.05). After a 10 s exposure, a 5.23 ± 1.64 log reduction was observed for Φ6 while MS2 remained resistant (0.04 ± 0.08 log10 reduction). Conversely, significant log reductions (P ≤ 0.05) were observed for TuV across all foam-based hand sanitizer products ranging from 0.07 ± 0.1 to 1.09 ± 0.22. An exposure time of 10 s (i.e., the typical rubbing time in real-world scenarios following hand sanitizer application) is likely sufficient for enveloped virus inactivation based on the inactivation of bacteriophage Φ6 by the tested commercially available products. However, longer exposure times or different hand sanitizer formulations may be required to achieve similar log reductions against non-enveloped viruses such as human norovirus based on the surrogates (MS2, TuV) tested.

COVID-19 is caused by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) as a pandemic infectious disease. So far, it has been known that this virus uses several receptors to enter the host cell, one of which is neuropilin-1 (NRP1). Also, one of the main causes of clinical manifestations, severity of disease, and mortality of patients is cytokine storm syndrome, one of these cytokines being interleukin (IL)-6. Our aim was to study the level of expression of NRP1 and IL-6 genes in COVID-19 patients by using peripheral blood mononuclear cells (PBMCs).

Our study population included the test group (80 patients with COVID-19) and the control group (30 healthy individuals). Venous blood was taken from all subjects. After isolating PBMCs from blood using Ficoll, RNA was extracted. Then, cDNA synthesis, the expression level of NRP1 and IL-6 compared to GAPDH housekeeping gene was measured by real-time PCR.

The level of NRP1 gene expression was increased significantly in COVID-19 different groups compared to the control group. Surprisingly, it was observed that the amount of NRP1 gene decreased in the vaccinated group compared to nonvaccinated groups. IL-6 gene expression was also significantly increased in all groups except vaccinated patients compared to the control group. Also, the results indicated that there was a positive and statistically considerable relationship between IL-6 expression level and NRP1 expression level (p = 0.03).

The significant increase in the expression of NRP1 and IL-6 genes in COVID-19 patients, especially in moderate and severe cases, indicates their potential involvement in the progression of the disease, which may serve as biomarkers of disease severity. Also, since these genes play an important role in causing severe inflammation, cytokine storm, and immunopathological complications of COVID-19, further investigations maybe needed to achieve therapeutic goals to control COVID-19 and similar diseases.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the etiologic agent involved in the coronavirus disease 2019 (COVID-19) pandemic. The development of infectious titration methods is crucial to provide data for a better understanding of transmission routes, as well as to validate the efficacy of inactivation treatments. Nevertheless, the low-throughput analytical capacity of traditional methods may be a limiting factor for a large screening of samples. The aim of the study was to develop a Real-Time Cell Analysis (RTCA) assay based on the measurement of cell impedance to quantify infectious SARS-CoV-2. The kinetics of cell impedance showed a virus-specific Cell Index (CI) drop. This enabled the correlation between viral concentrations and time at which a 50 % drop in CI values was observed (tCI50), with establishment of a standard curve. In parallel, the improved Spearman and Kärber method was used to quantify infectious titer since the virus-induced CI drop is correlated to the Cytopathic Effect. The estimated uncertainty was respectively 0.57, 0.36, and 0.26 log10 with 4, 8, and 16 wells per dilution. Thus, the RTCA assay is a powerful tool with a greatly simplified workflow for effective risk assessment in the field of food and environmental virology.

Objective: To understand how student perceptions of physical health and generalized concern about infection influenced engagement in COVID-19 preventive behaviors. Participants: 418 full-time undergraduate and graduate students attending a public university in South Carolina, USA. Methods: A self-administered survey was distributed during the 2020-2021 academic year. The health belief model, structural equation modeling, and regression methods were used to evaluate associations between students' perceived physical health and the use of CDC-recommended mitigation strategies. Results: Our findings suggest that an individual's perception of their own physical health impacted engagement in preventive behaviors by influencing concerns about disease severity (p = 0.01) and susceptibility (p = 0.03). However, perceived physical health was not associated with perceived benefits (p = 0.21), barriers (p = 0.57), or self-efficacy (p = 0.62) of mitigation strategies. Conclusions: Intrapersonal factors may play a strong role in the way a student undertakes disease control and prevention.

Coronavirus disease (COVID-19) is still a severe concern, especially in Africa with suboptimal intention rates of vaccination. This flagged the requirement of plant-based remedies as an alternative treatment. In this study we integrated metabolomics and chemometrics approaches with In silico and In vitro approaches to accelerate and unravel compounds from commonly used South African plants that may inhibit SARS-CoV-2 main protease. The selected commonly used plants, Artemisia afra and Artemisia annua, were found to be non-toxic against Vero cells, as determined by the resazurin cell viability assay. Metabolites profiling revealed eighty-one compounds and the top three hit compounds, quercetin 3-O-(6"-acetyl-glucoside), 2"-O-acetylrutin, and quercetin 3-(6"-malonyl-glucoside), had binding affinities of -9.3 kcal/mol, -9.5 kcal/mol, and -9.3 kcal/mol, respectively. The 2"-O-acetyl group of the rutin moiety and quercetin moiety produces a hydrogen bond with the amide nitrogen of His41 and with the side chain carboxylate of Cys145, respectively. Molecular dynamics simulations revealed a stable binding of the docked complexes. In silico observations were validated by In vitro bioassay, which flagged the ability of these compounds to inhibit SARS-CoV-2 3CLpro. The collected analysed data of this study does not only draw special attention to the surfaced 2"-O-acetylrutin as the best suitable inhibitor of SARS-CoV-2 3CLpro, but also indirectly reveals the importance of integrating metabolomics and chemometrics approaches with In silico and In vitro approaches to accelerate and unravel compounds from South African commonly used plants.

The use of face masks has proven to be an effective preventive measure during the COVID-19 pandemic. However, concerns have emerged regarding the safety of metal (nano)particles incorporated into face masks for antimicrobial purposes. Specifically, this review examines the risks associated with TiO2 nanoparticles (NPs), which are classified as a possible human carcinogen. The inhalation of TiO2 NPs can cause multiple adverse effects, including oxidative stress, pulmonary inflammation, histopathological changes, and (secondary) genotoxicity. Different aspects are discussed, such as the composition and filtration efficiency of face masks, the antimicrobial mode of action and effectiveness of various metals, and the hazards of TiO2 NPs to human health, including exposure limits. A conservative risk assessment was conducted using different worst-case scenarios of potential (sub)chronic TiO2 exposure, derived from published leaching experiments. Most face masks are considered safe, especially for occasional or single use. However, the nanosafety of a minority of face masks on the European market may be inadequate for prolonged and intensive use. Important uncertainties remain, including the risks of combined exposure to TiO2 NPs and silver biocides, and the lack of direct exposure measurements. Considering the potential safety issues and the limited added protective value of TiO2 NPs, it is recommended to ban all applications of TiO2 in face masks based on the precautionary principle.

Inhaled aerosols impact human health by depositing harmful species in the lungs (e.g., metals and organic pollutants) and act as a key pathway for airborne disease transmission. Aerosol inhalation is highly size-dependent, with smaller particles (particulate matter <2.5 μm, PM2.5) depositing deeper in the lungs (e.g., alveoli) leading to strong correlations between PM2.5 and mortality, along with other respiratory and cardiovascular diseases. A longstanding challenge for detailed aerosol chemical analysis is that most PM2.5 health studies collect offline samples, which are subsequently analyzed offsite, requiring high-cost collectors and significant downstream effort and cost. Herein, we present a low-cost, miniature 3D-printed impactor coupled to a microfluidic channel to allow for downstream analysis of PM in liquid. After size-segregated collection of airborne particles within the device, water is flowed through a microfluidic channel that resuspends insoluble particles or dissolves soluble particles. Size-dependent collection efficiencies (50% cutoff diameters, d50's) for the supermicron (PM>1) impactor were 0.8 and 1.0 μm using monodisperse (polystyrene latex spheres) and polydisperse (red-fluorescent spheres) standards, respectively. Coarse (PM>2.5) impactor d50's were 2.4 and 2.6 μm, respectively. Optical photothermal infrared (O-PTIR) and Raman microspectroscopy confirmed collected particle composition. The sizes of re-entrained PSLs (1, 1.25, and 1.5 μm) were measured to have diameters of 1.0, 1.2, and 1.5 μm, respectively, with a Coulter Counter, indicating the successful downstream analysis of collected particles without modification during impaction and resuspension. Soluble particles (ammonium sulfate) were dissolved by the flowing water and measured with ion chromatography. This study shows that 3D-printed impactors are capable of collecting particles with a well-defined size cut, as well as nondestructively resuspending and chemically analyzing the particles. These 3D-printed devices are a miniaturized, low-cost (<$2) option that sets the stage for semicontinuous microfluidic analysis of size-selected aerosols to evaluate health impacts ranging from toxin exposure to disease transmission.

The COVID-19 pandemic of 2020 was unprecedented in its devastating impact on the global economy, public health, travel and tourism, education, sports, religion, and social lives. Studies conducted thereafter on the disease and its causative agent, SARS-CoV-2, have highlighted the need for effective and sustainable public health interventions.

This study investigated the prevalence and endemicity of SARS-CoV-2 infection in pet dogs using immunochromatography assay (IC) and quantitative reverse transcriptase-polymerase chain reaction (RT-qPCR) of their blood, rectal swabs, and nasal swabs in Ibadan, Oyo State, Nigeria between 2022 and 2024.

For the IC, positivity rates of 11.7% (23/197), 85.7% (6/7), and 100% (3/3) were recorded for 2022, 2023 and 2024 while for the RT-qPCR, positivity rates of 37.9% (11/29), 33.3% (2/6) and 100% (3/3) were recorded for 2022, 2023 and 2024. This repeated detection of SARS-CoV-2 in three of the dogs tested over the three-year period suggests continuous shedding of the virus by these animals and indicates endemicity of the virus in the study area. Findings highlight the urgent need for optimized SARS-CoV-2 rapid diagnostic tools tailored for veterinary applications to ensure rapid and reliable detection of the virus, especially in resource-constrained settings.

Considering the zoonotic nature of SARS-CoV-2 and its potential for mutation into more virulent strains that can be transmissible to humans, the findings of this study have significant implications for public health and implementation of One Health strategies by policymakers, and highlight the need for robust SARS-CoV-2 surveillance in domestic animals to mitigate potential zoonotic risks.

The SARS-CoV-2 pandemic had widespread and severe impacts on both the global economy and human health. Facing the continuously mutating virus, this crisis has heightened concerns among consumers and businesses regarding viral transmission through seafood, particularly in the face of emerging, unknown viruses, underscoring our preparedness gaps. This review provides a succinct overview of the survival mechanisms of prevalent viruses in seafood, examines potential transmission pathways to humans during seafood processing, and discusses strategies for mitigating their spread throughout the seafood supply chain. Furthermore, the discussion highlights emerging trends in innovative antiviral technologies aimed at enhancing food safety. Person-to-person transmission remains the most likely source of infection within the supply chain. Therefore, it is still imperative to adhere to the implementation of standard processes, namely good manufacturing practices (GMP) and good hygiene practices (GHP), in the seafood business. In light of the significant losses caused by this crisis and the persistent presence of various viruses within the seafood supply chain, efforts are needed to implement predictive and preventive measures against potential emerging viruses. Future research should focus on monitoring and limiting viral transmission by integrating Industry 4.0 applications, smart technologies, and antiviral packaging, maximizing the potential of these emerging solutions.

Surfaces contaminated with enveloped viruses, such as severe acute respiratory syndrome coronavirus 2 and influenza virus, can potentially spread illness via hand contact. Often, the efficacy of hand hygiene interventions relies on virus recovery from hands. However, the recovery of bacteriophage phi6 (Φ6), a recommended surrogate for enveloped viruses, from the entire hands using the ASTM E2011-21 standard has not been optimized. For Φ6 recovery from the hands, three eluents [lysogeny broth (LC), tryptic soy broth (TSB), and 1.5% beef extract (BE)] and three recovery methods [glove juice method (GJM), hand rinsing, and modified dish method] were examined. The effects of inoculum application on either the palmar surface or the whole hand were compared, and virus recovery was assessed under wet and dry conditions to identify the optimal combinations for maximizing Φ6 recovery. Statistical differences among methods, inoculum application, and recovery types were identified. While no statistical difference was observed among the eluents (P = 0.281), LC demonstrated the highest Φ6 recovery efficiency, while TSB and BE had comparable recoveries. Two-way interaction effects were observed between method type vs. application type (P ≤ 0.05), method type vs. recovery type (P ≤ 0.05), and application type vs. recovery type (P ≤ 0.05), indicating these factors influencing one another. Additionally, no Φ6 recovery was obtained for the dry basis recovery type and the GJM method type. Based on the present study, to maximize Φ6 recovery from the hands during hand hygiene studies, inoculum should be applied to the palmar surface and recovered while it is still wet using LC.

The COVID-19 pandemic was one of the most serious public health events of the 21st century, which had a profound impact on the entire human society and sparked extensive debate and research on public health crisis management. To clarify the development path of the issue and to discover the structure and internal logic of related studies, this study conducted a scientometric analysis (co-citation analysis, co-occurrence analysis, cooperation network analysis, knowledge domain migration analysis) of 8814 publications from the Web of Science Core Collection and PubMed using CiteSpace, and drew the following conclusions: (1) The research focuses on empirical studies in medicine and other fields, and expands to non-medical fields such as "social media", "COVID-19 lockdown", and "air quality"; (2) The USA, UK, Italy and other major developed countries in Europe and America are leading the research trend, while developing countries, notably China, India and Brazil have become the important contributors to the study of this issue in different ways; (3) The research results at this stage are mainly in the fields of medicine, health and biology and are cited internally, but are also developing in the direction of economics, political, environmental and other fields. Finally, this study summarises some of the issues that should be of concern to public health crisis management in the post-pandemic era, in the hope of providing some insight for researchers on this issue.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is involved in aerosol particles and droplets excreted from a coronavirus disease 2019 (COVID-19) patient. Such aerosol particles or droplets including infectious virions can be attached on fomite, so fomite is not a negligible route for SARS-CoV-2 transmission within a community, especially in indoor environment. This necessarily evokes a need of fomite disinfection to remove virions, but the extent to which fomite disinfection breaks off virus transmission chain in indoor environment is still elusive. In this study, we evaluated the fomite disinfection effectiveness on COVID-19 case number using network analysis that reproduced the reported indoor outbreaks. In the established network, virus can move around not only human but also air and fomite while growing in human and decaying in air and on fomite, and infection success was determined based on the exposed virus amount and the equation of probability of infection. The simulation results have demonstrated that infectious virions on fomite should be kept less than a hundred to sufficiently reduce COVID-19 case, and every-hour disinfection was required to avoid stochastic increase in the infection case. This study gives us a practical disinfection manner for fomite to control SARS-CoV-2 transmission in indoor environment.

Water supply and sanitation are essential household services frequently shared in resource-poor settings. Shared sanitation can increase the risk of enteric pathogen transmission due to suboptimal cleanliness of facilities used by large numbers of individuals. It also can potentially increase the risk of respiratory disease transmission. As sanitation is an essential need, shared sanitation facilities may act as important respiratory pathogen transmission venues even with strict control measures such as stay-at-home recommendations in place. This analysis explores how behavioral and infrastructural conditions surrounding shared sanitation may individually and interactively influence respiratory pathogen transmission. We developed an individual-based community transmission model using COVID-19 as a motivating example parameterized from empirical literature to explore how transmission in shared latrines interacts with transmission at the community level. We explored mitigation strategies, including infrastructural and behavioral interventions. Our review of empirical literature confirms that shared sanitation venues in resource-poor settings are relatively small with poor ventilation and high use patterns. In these contexts, shared sanitation facilities may act as strong drivers of respiratory disease transmission, especially in areas reliant on shared facilities. Decreasing dependence on shared latrines was most effective at attenuating sanitation-associated transmission. Improvements to latrine ventilation and handwashing behavior were also able to decrease transmission. The type and order of interventions are important in successfully attenuating disease risk, with infrastructural and engineering controls being most effective when administered first, followed by behavioral controls after successful attenuation of sufficient alternate transmission routes. Beyond COVID-19, our modeling framework can be extended to address water, sanitation, and hygiene measures targeted at a range of environmentally mediated infectious diseases.

The Coronavirus disease 2019 (COVID-19) pandemic has caused significant global threats, as Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2) is primarily transmitted through airborne droplets and bioaerosols. Healthcare workers are particularly at high risk, yet there is limited research on the presence of SARS-CoV-2 in bioaerosols within healthcare facilities in Malaysia. This study aimed to determine the presence and viability of SARS-CoV-2 and its variants of concern in the air and ventilation systems of designated COVID-19 facilities from December 2021 to February 2022. Samples were collected from two hospitals and one quarantine centre (QC), including medical wards, intensive care units, emergency departments, and QC halls. Air samples were obtained using air samplers, while surface samples were taken from return air grilles. SARS-CoV-2 ribonucleic acid (RNA) and its variants were detected using reverse transcription droplet digital polymerase chain reaction (RT-ddPCR) and PCR-based genotyping, respectively. Results showed that Hospital A had a higher rate (24.6%) of positive samples than Hospital B (8.8%). Surface samples had a higher positivity rate (50.0%) compared to air samples (8.3%). The detected variants included delta (34.7%), a mixture of delta and omicron (8.7%), non-variant of concern (non-VOC) (8.7%), and omicron (4.3%). This study emphasizes the need for strict airborne infection control measures for healthcare workers.

The increasing need for effective antiviral strategies has led to the development of innovative surface coatings to combat the transmission of viruses via fomites. The aim of this review is to critically assess the efficacy of antiviral coatings in mitigating virus transmission, particularly those activated by visible light. The alarm created by the COVID-19 pandemic, including the initial uncertainty about the mechanisms of its spread, attracted attention to fomites as a possible source of virus transmission. However, later research has shown that surface-dependent infection mechanisms need to be carefully evaluated experimentally. By briefly analyzing virus-surface interactions and their implications, this review highlights the importance of shifting to innovative solutions. In particular, visible-light-activated antiviral coatings that use reactive oxygen species such as singlet oxygen to disrupt viral components have emerged as promising options. These coatings can allow for obtaining safe, continuous, and long-term active biocidal surfaces suitable for various applications, including healthcare environments and public spaces. This review indicates that while the significance of fomite transmission is context-dependent, advances in material science provide actionable pathways for designing multifunctional, visible-light-activated antiviral coatings. These innovations align with the lessons learned from the COVID-19 pandemic and pave the way for sustainable, broad-spectrum antiviral solutions capable of addressing future public health challenges.

This study aims at exploring a general and adaptive control strategy to confront the rapid evolution of an emerging infectious disease ('Disease X'), drawing lessons from the management of COVID-19 in China. We employ a dynamic model incorporating age structures and vaccination statuses, which is calibrated using epidemic data. We therefore estimate the cumulative infection rate (CIR) during the first epidemic wave of Omicron variant after China relaxed its zero-COVID policy to be 82.9% (95% CI: 82.3%, 83.5%), with a case fatality rate (CFR) of 0.25% (95% CI: 0.248%, 0.253%). We further show that if the zero-COVID policy had been eased in January 2022, the CIR and CFR would have decreased to 81.64% and 0.205%, respectively, due to a higher level of immunity from vaccination. However, if we ease the zero-COVID policy during the circulation of Delta variant from June 2021, the CIR would decrease to 74.06% while the CFR would significantly increase to 1.065%. Therefore, in the face of a 'Disease X', the adaptive strategies should be guided by multiple factors, the 'zero-COVID-like' policy could be a feasible and effective way for the control of a variant with relative low transmissibility. However, we should ease the strategy as the virus matures into a new variant with much higher transmissibility, particularly when the population is at a high level of immunity.

Ultraviolet germicidal irradiation (UVGI) technology can inhibit the environmental transmission of airborne pathogens, but the dose-response behavior of airborne human coronavirus and wavelength-specific inactivation mechanisms are not well understood. This study investigated three competitive UVC sources for their inactivation efficacy and mechanisms against human coronavirus OC43 (HCoV-OC43). Results showed the following order of inactivation efficacy: 222-nm KrCl excimer lamp > 263-nm UV-LEDs > 254-nm low-pressure mercury lamp. The 222-nm KrCl excimer lamp achieved a 5-log inactivation of aerosolized HCoV-OC43 with a dose of less than 1 mJ/cm², while the 263-nm UV-LEDs had the highest genome damage rate constant at 7.08 ± 0.85 mJ/cm². Although 222-nm Far-UVC caused less genome damage, it affected viral proteins more significantly, specifically the nucleocapsid (N) and spike (S) proteins, which lead to compromising capsid integrity and binding ability to host cells. Capsid integrity RT-qPCR and binding assay RT-qPCR used in this study could better monitor infectivity of airborne coronavirus than standard RT-qPCR. Additionally, significant lipid oxidation of HCoV-OC43 was observed under 222-nm irradiation, potentially impacting overall inactivation efficacy. This study provides detailed evidence on the effects of different UVC wavelengths on airborne HCoV-OC43, contributing to the optimization of UVC irradiation for indoor bioaerosol disinfection.

We performed triplicate and long-time all-atom molecular dynamics simulations to investigate the structures and dynamics of the SARS-CoV-2 spike glycoprotein (S-protein) for a broad range of pH = 1 through 11 and temperatures of 3°C through 75°C. This study elucidates the complex interplay between pH and thermal effects on S-protein structures, with implications for its behavior under diverse conditions, and identifies the RBD as a primary region of the structural deviations. We found: 1) Structural deviations in the S-protein backbone at pH = 1 are 210% greater than those at pH = 7 at 75°C, with most of the deviations appearing in the receptor-binding domain (RBD). Smaller structural changes are observed at pH = 3 and 11. 2) The pH and thermal conditions impact on the protein structures: substantial acidic and basic conditions expand the protein's solvent exposure, while high heat contracts. This effect is primarily pH-driven at extreme acidity and thermo-driven at moderate pH. 3) The Gibbs free energy landscape reveals that pH as the main driver of structural changes. 4) The parametrized methods enable the predictions of the S-protein properties at any reasonable pH and thermal conditions without explicit MD simulations.

The World Health Organization (WHO) has determined a series of guidelines to contain the advance and spread of COVID-19 and other influenza viruses. Among them, frequent hand hygiene has been widely recommended, resulting in an increased consumption of alcohol-based antiseptic products or synthetic molecules. However, when used in excess, these products might cause adverse consequences for human health, such as dermatitis, and for the environment, i.e., the selection of resistant bacterial genotypes. One of the alternatives to overcome this problem is the replacement of common antiseptics by formulations based on natural bioactive compounds with antimicrobial/antiviral activity. In addition, by nanostructuring formulations, it is possible to increase the bioavailability, stability, solubility, and absorption of bioactives in biological systems. In this sense, this study aimed to develop an antiseptic nanoemulsion based on natural bioactive compounds with virucidal activity against SARS-CoV-2. For that, oil-in-water (O/W) nanoemulsions were prepared, being the oil phase composed by Melaleuca alternifolia essential oil, quercetin, PEG400, and surfactants, while the aqueous phase presented carrageenan and purified water. Physicochemical characterization and stability studies were developed to evaluate the viability of the formulations over time. In addition, bactericidal activities against Staphylococcus aureus and antiviral activity against SARS-CoV-2 were determined by in vitro assays. As a result, the average size of the nanoparticles was recorded at 150 nm, with a Polydispersity Index (PdI) of 0.2 and a zeta potential around -10.0 mV. The stability of nanoformulations indicated the occurrence of quercetin-dependent creaming and sedimentation. In addition, the products presented a minimum shelf-life of 3 months. Regarding the bactericidal activity, a minimum inhibition concentration of 1.25 % for S. aureus was found. The cytotoxicity and antiviral assays revealed that the nano-based products showed 100 % of viral replication inhibition and proved to be safe for epithelial cells. In conclusion, two antiseptic nanoformulations with high anti-SARS-CoV-2 activity and great industrial and pharmacological potential were developed.

Coronavirus disease 2019 (COVID-19) caused many consumers in the United States to change their perceptions and food handling practices at the height of the pandemic. We used a quantitative-qualitative mixed-method approach to assess consumers' risk perceptions and food safety practices during the COVID-19 pandemic. Nine waves of surveys were distributed to an online consumer panel over a 13-month period (April 2020-May 2021), and four waves of focus groups were conducted (May-July 2020 and June 2021). While the pandemic elevated peoples' perceptions of risks related to food safety practices, many consumers were reverting to past behaviors by May 2021. Participants asserted high confidence in their food safety measures; however, they perceived a low risk of contracting COVID-19 from food. Contrasts in food handling became apparent when assessing different age groups; observations revealed that practices in households with high-risk individuals differed significantly from those without. Although not recommended, the practice of washing produce with soap was consistent, predicting a possible continuation of this practice over time. This study highlights various factors that food safety educators and policymakers need to consider for effective communication about risks associated with food safety practices in preparation for pandemics and other major health events.

Hospital-associated infections (HAIs) are a significant burden on healthcare systems. Ultraviolet light (UVL) disinfection has emerged as a potential method for reducing HAIs by decontaminating healthcare environments.

To evaluate the effectiveness of UVL in reducing HAIs across various hospital settings.

A systematic literature review was conducted following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines, with searches performed in PubMed, Web of Science, and Scopus through July 2023. Peer-reviewed observational and experimental studies assessing UVL's impact on HAIs were included. Data extraction focused on study characteristics, UVL type, and infection outcomes. Studies focusing on environmental contamination or lacking sufficient data were excluded.

Twenty-five studies met the inclusion criteria. UVL types included ultraviolet-C (UV-C), pulsed xenon UV (PX-UV), and unspecified UVL. For PX-UV, several studies reported reductions in infection rates, with some showing up to a 70% decrease in Clostridioides difficile infection rates, especially in high-risk areas such as intensive care units, though results vary across settings, with some studies not observing significant improvements. UV-C disinfection has also been found to reduce HAIs, with its effectiveness varying based on the healthcare setting and targeted pathogens, and it is most effective when used in conjunction with other infection control strategies.

UVL disinfection technologies have demonstrated potential in reducing HAIs, particularly when integrated into a comprehensive infection prevention strategy. Their effectiveness, however, varies by application, pathogen type, and healthcare setting. Further research is needed to optimize UVL implementation and assess its cost-effectiveness in diverse clinical environments.

The COVID-19 pandemic has led to instructions and suggestions from governments and experts to maintain social (physical) distance between people to prevent aerosol transmission of the virus, which is now becoming the norm. Thus, we examined whether the pandemic extended the distance between personal belongings.

We recruited 68 university students and instructed them to place their belongings on a long table following another participant (i.e., confederate). We measured the physical distance between the two belongings (i.e., the participant's and the confederate's). We collected data between June 10, 2022 and January 23, 2023. Pre-pandemic data was from Ariga (2016). Analysis was completed with one-tailed t-tests.

Compared with the pre-pandemic results, via one-tailed t-test, the distance between the two belongings during the pandemic was significantly longer. Our results supported the hypothesis that the psychological framework for processing people's belongings has dramatically changed during this pandemic.

This change may have been driven by social distancing practices or an increase in perceived vulnerability to disease. Our results provide new implications for future public spatial design, in other words, not only the distance between people, but also the distance between their belongings.

The development of new strategies to produce nanomaterials that can be used as personal protective equipment with antiviral activity and low toxicity is crucial. Electrospun ultrathin fibers have attracted considerable attention due to their potential for biomedical applications, including antiviral activity. Herein, we electrospun different grades of commercially available polyamide to produce ultrathin fibers and investigate their antiviral activity against SARS-CoV-2 Gamma lineage (P.1). We evaluated the morphology, chemical composition, and mechanical properties of the ultrathin fibers. We also investigated the in vitro cytotoxicity, hemolytic activity, and antiviral activity against SARS-CoV-2 Gamma lineage (P.1) of the developed ultrathin fibers. The ultrathin fibers had the following diameters and elastic moduli: (i) unmodified crude ultrathin polyamide (PAP) 0.59 μm and 3 MPa, (ii) polyamide Biotech (PAAM) 0.74 μm and 2.2 MPa, and (iii) Amni Virus-Bac OFF polyamide (PAVB) 0.69 μm and 1.06 MPa. The ultrathin PAP fibers showed increased antiviral activity compared to the other ultrathin fibers (PAAM and PAVB). None of the electrospun fibers showed cytotoxicity at the lowest concentration (12.5%). Additionally, hemolysis tests demonstrated a nonhemolytic profile for all fiber groups, reinforcing their biocompatibility and suitability for biomedical applications. The antiviral properties of the electrospun ultrathin PAP fibers, combined with their noncytotoxic and nonhemolytic characteristics, highlight their potential to be used as personal protection against SARS-CoV-2.

The stability of influenza virus in respiratory particles varies with relative humidity (RH) and protein content. This study investigated the decay, or loss of infectivity, of influenza A virus (IAV) in 1-μL respiratory droplets deposited on a surface with varying concentrations of mucin, one of the most abundant proteins in respiratory mucus, and examined the localization of virions within droplets. IAV remained stable at 0.1% and 0.5% mucin in phosphate-buffered saline (PBS) over 4 h at 20%, 50%, and 80% RH, with a maximum decay of 1.2 log10/mL. In contrast, in pure PBS droplets, the virus decayed by at least 2.6 log10/mL after 4 h at 50% and 80% RH. Mucin's protective effect was independent of its concentration, except at 80% RH after 4 h. Confocal microscopy of the particles revealed that at 20% and 50% RH, mucin led to thicker coffee rings and dendritic patterns where virions colocalized with mucin. At 80% RH, no morphological difference was observed between PBS-only and mucin-containing droplets, but virions still colocalized with mucin in the center of droplets with 0.5% mucin. Analysis by digital droplet PCR showed that mucin helped maintain virus integrity. To our knowledge, this is the first study to localize influenza virus in model respiratory droplets. The results suggest that mucin's colocalization with virions in droplets may protect the virus from environmental stressors, enhancing its stability.

SARS-CoV-2 infection has led to a range of long-lasting symptoms, collectively referred to as long COVID. Current research highlights the critical role of angiotensin-converting enzyme 2 (ACE2) in regulating gut microbiota diversity, vascular function, and homeostasis within the renin-angiotensin system (RAS). ACE2 is utilized by the SARS-CoV-2 virus to enter host cells, but its downregulation following infection contributes to gut microbiota dysbiosis and RAS disruption. These imbalances have been linked to a range of long COVID symptoms, including joint pain, chest pain, chronic cough, fatigue, brain fog, anxiety, depression, myalgia, peripheral neuropathy, memory difficulties, and impaired attention. This review investigates the dysregulation caused by SARS-CoV-2 infection and the long-term effects it has on various organ systems, including the musculoskeletal, neurological, renal, respiratory, and cardiovascular systems. We explored the bidirectional interactions between the gut microbiota, immune function, and these organ systems, focusing on how microbiota dysregulation contributes to the chronic inflammation and dysfunction observed in long COVID symptoms. Understanding these interactions is key for identifying effective therapeutic strategies and interventional targets aimed at mitigating the impact of long COVID on organ health and improving patient outcomes.

Lung cancer has a poor prognosis, and further improvements in outcomes are needed. Radiotherapy plays an important role in the treatment of unresectable lung cancer, and there have been recent developments in the field of radiotherapy for the management of lung cancer. However, to date, there have been few reviews on the improvement in treatment outcomes associated with high precision radiotherapy for lung cancer. Thus, this review aimed to summarize the recent developments in radiotherapy techniques and indicate the future directions in the use of radiotherapy for lung cancer. Stereotactic body radiotherapy (SBRT) for unresectable stage I lung cancer has been reported to improve local control rates without severe adverse events, such as radiation pneumonitis. For locally advanced lung cancer, a combination of chemoradiotherapy and adjuvant immune checkpoint inhibitors dramatically improves treatment outcomes, and intensity-modulated radiotherapy (IMRT) enables safer radiation therapy with less frequent pneumonitis. Particle beam therapy, such as carbon-ion radiotherapy and proton beam therapy, has been administered as advanced medical care for patients with lung cancer. Since 2024, it has been covered under insurance for early stage lung cancer with tumors ≤ 5 cm in size in Japan. In addition to chemotherapy, local ablative radiotherapy improves treatment outcomes in patients with oligometastatic stage IV lung cancer. A particular problem with radiotherapy for lung cancer is that the target location changes with respiratory motion, and various physical methods have been used to control respiratory motion. Recently, coronavirus disease has had a major impact on lung cancer treatment, and cancer treatment during situations, such as the coronavirus pandemic, must be performed carefully. To improve treatment outcomes for lung cancer, it is necessary to fully utilize evolving radiotherapy modalities, and the role of radiotherapy in lung cancer treatment is expected to increase.

The aim of this study was to analyze clinical strategies supported by validated references during two of the most frequent dental emergencies (i.e. restorative and endodontic treatment) in the COVID-19 pandemic. Coronavirus disease 2019 (COVID-19) was caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the causative agent of an emergency in the health system worldwide and a potentially fatal disease. Person-to-person transmission of SARS-CoV-2 through aerosol and droplets led to extensive preventive measures to contain COVID-19 outbreak. Dental care providers have been exposed to a high risk of SARS-CoV-2 infection, due to the face-to-face communication and the exposure to saliva, blood, and other body fluids during routine interventions; this can also contribute to a high risk for cross-infection, even though dentist usually cope with those situations in everyday practice. Restorative and endodontic emergencies represented a high proportion of dental emergencies, with prolonged exposure time for dentists/endodontists in contact with suspected or confirmed infected patients. Lack of knowledge and undefined progression controlled the decision-making in clinical dentistry. The dynamicity of the situation determined change of views and recommendations in dental setting. The implementation of strict restorative and endodontics protocols are aimed at preventing circumstances similar to those observed with COVID-19.

This study presents an advanced airborne transmission risk assessment model that integrates both short- and long-range routes in the spread of respiratory viruses, building upon the CERN Airborne Model for Indoor Risk Assessment (CAiMIRA) and aligned with the new World Health Organization (WHO) terminology. Thanks to a two-stage exhaled jet approach, the model accurately simulates short-range exposures, thereby improving infection risk predictions across diverse indoor settings. Key findings reveal that in patient wards, the short-range viral dose is 10-fold higher than the long-range component, highlighting the critical role of close proximity interactions. Implementation of FFP2 respirators resulted in a remarkable 13-fold reduction in viral dose, underscoring the effectiveness of personal protective equipment (PPE). Additionally, the model demonstrated that an 8 h exposure in a poorly ventilated office can equate to the risk of a 15 min face-to-face, mask-less interaction, emphasizing the importance of physical distancing and source control. We also found in high-risk or low-occupancy settings, that secondary transmission is driven more by overall epidemic trends than by the presence of individual superspreaders. Monte Carlo simulations across various scenarios, including classrooms and offices, validate the model's robustness in optimizing infection prevention strategies. These findings support targeted interventions for short- and long-range exposure to reduce airborne transmission.

Hospital- and nursing-care-acquired infections are a growing problem worldwide, especially during epidemics, posing a significant threat to older adults in geriatric settings. Intense research during the COVID-19 pandemic highlighted the prominent role of aerosol transmission of pathogens. Aerosol particles can easily adsorb different airborne pathogens, carrying them for a long time. Understanding the dynamics of airborne pathogen transmission is essential for controlling the spread of many well-known pathogens, like the influenza virus, and emerging ones like SARS-CoV-2. Particles smaller than 50 to 100 µm remain airborne and significantly contribute to pathogen transmission. This review explores the journey of pathogen-carrying particles from formation in the airways, through airborne travel, to deposition in the lungs. The physicochemical properties of emitted particles depend on health status and emission modes, such as breathing, speaking, singing, coughing, sneezing, playing wind instruments, and medical interventions. After emission, sedimentation and evaporation primarily determine particle fate. Lung deposition of inhaled aerosol particles can be studied through in vivo, in vitro, or in silico methods. We discuss several numerical lung models, such as the Human Respiratory Tract Model, the LUng Dose Evaluation Program software (LUDEP), the Stochastic Lung Model, and the Computational Fluid Dynamics (CFD) techniques, and real-time or post-evaluation methods for detecting and characterizing these particles. Various air purification methods, particularly filtration, are reviewed for their effectiveness in healthcare settings. In the discussion, we analyze how this knowledge can help create environments with reduced PM2.5 and pathogen levels, enhancing safety in healthcare and nursing-care settings. This is particularly crucial for protecting older adults, who are more vulnerable to infections due to weaker immune systems and the higher prevalence of chronic conditions. By implementing effective airborne pathogen control measures, we can significantly improve health outcomes in geriatric settings.

We constructed a rapid infection risk assessment model for contacts of COVID-19. The improved Wells-Riley model was used to estimate the probability of infection for contacts of COVID-19 in the same place and evaluate their risk grades. We used COVID-19 outbreaks that were documented to validate the accuracy of the model. We analyzed the relationship between controllable factors and infection probability and constructed common scenarios to analyze the infection risk of contacts in different scenarios. The model showed the robustness of the fitting (mean relative error = 5.89%, mean absolute error = 2.03%, root mean squared error = 2.03%, R2 = 0.991). We found that improving ventilation from poorly ventilated to naturally ventilated and wearing masks can reduce the probability of infection by about two times. Contacts in places of light activity, loud talking or singing, and heavy exercise, oral breathing (e.g., gyms, KTV, choirs) were at higher risk of infection. The model constructed in this study can quickly and accurately assess the infection risk grades of COVID-19 contacts. Simply opening doors and windows for ventilation can significantly reduce the risk of infection in certain places. The places of light activity, loud talking or singing, and heavy exercise, oral breathing, should pay more attention to prevent and control transmission of the epidemic.

COVID-19 disease, triggered by SARS-CoV-2 virus infection, has led to more than 7.0 million deaths worldwide, with a significant fraction of recovered infected people reporting postviral symptoms. Smart surfaces functionalized with nanoparticles are a powerful tool to inactivate the virus and prevent the further spreading of the disease. Literature reports usually focus on the role of nanomaterial composition and size dispersion in evaluating their efficacy against SARS-CoV-2. Here, the anti-SARS-CoV-2 activity of oleylamine (OAm) used as a capping agent of silver nanoparticles is quantified for the first time. Spherical hydrophobic nanoparticles with 8 ± 2 nm diameter were prepared and characterized by Fourier transform infrared, dynamic light scattering, and transmission electron microscopy techniques. Biological assays showed that microgram amounts of nanoparticles, deposited on nonwoven textile obtained from surgical masks, efficiently inactivated up to 99.6(2)% of the virus with just 2 min of exposure. The virucidal activity of the corresponding amount of free OAm has been determined as well, reaching up to 67(1)% of activity for an exposure time of 10 min. Inductively coupled plasma optical emission spectrometry results pointed out a low leaching out of the nanoparticles in contact with water or culture medium. All in all, these results propose the capping molecules as an important chemical variable to be taken into account in the design of fast, efficient, and long-lasting anti-SARS-CoV-2 coatings.

With polymer nanoparticles now playing an influential role in biological applications, the synthesis of nanoparticles with precise control over size, shape, and chemical functionality, along with a responsive ability to environmental changes, remains a significant challenge. To address this challenge, innovative polymerization methods must be developed that can incorporate diverse functional groups and stimuli-responsive moieties into polymer nanostructures, which can then be tailored for specific biological applications. By combining the advantages of emulsion polymerization in an environmentally friendly reaction medium, high polymerization rates due to the compartmentalization effect, chemical functionality, and scalability, with the precise control over polymer chain growth achieved through reversible-deactivation radical polymerization, our group developed the temperature-directed morphology transformation (TDMT) method to produce polymer nanoparticles. This method utilized temperature or pH responsive nanoreactors for controlled particle growth and with the added advantages of controlled surface chemical functionality and the ability to produce well-defined asymmetric structures (e.g., tadpoles and kettlebells). This review summarizes the fundamental thermodynamic and kinetic principles that govern particle formation and control using the TDMT method, allowing precision-engineered polymer nanoparticles, offering a versatile and an efficient means to produce 3D nanostructures directly in water with diverse morphologies, high purity, high solids content, and controlled surface and internal functionality. With such control over the nanoparticle features, the TDMT-generated nanostructures could be designed for a wide variety of biological applications, including antiviral coatings effective against SARS-CoV-2 and other pathogens, reversible scaffolds for stem cell expansion and release, and vaccine and drug delivery systems.

Disposable filtering face piece respirators (FFRs) are not approved for reuse as standard of care. However, lessons learnt from the SARS-CoV-2 pandemic, FFRs decontamination and reuse may be needed as crisis capacity strategy to ensure availability in medical facilities. We studied a decontamination methodology based on atmospheric pressure plasma technology, which allows for rapid, contact-free decontamination without utilisation of harmful chemicals, and suitable to access small pores and microscopic filters openings. Promising performances in terms of bioburden reduction (Log6) were achieved while imparting mainly transient chemical surface modifications to the masks filtering layers. The plasma decontamination process proposed was also considered in terms of the environmental impact of re-use technology for FFR medical devices in order to understand its sustainability. This study assessed the feasibility of an atmospheric pressure plasma approach for the decontamination of disposable filtering face piece respirators (FFR) or respiratory masks commonly used in hospital settings.