Infectivity of SARS-CoV-2 and Other Coronaviruses on Dry Surfaces: Potential for Indirect Transmission

Evaluation of awareness and performance towards COVID-related disinfectant use: a comparative study between Jordan and United Arab Emirates

BACKGROUND

The World Health Organization recommended the use of chemical-based disinfectants as an effective prevention of the COVID-19 pandemic. However, calls for poisoning were reported in several medical centers. The widespread use of chemical-based disinfectants as a preventive measure during the COVID-19 pandemic has underscored potential gaps in community awareness and performance, posing health risks. This study evaluates and compares levels of awareness and performance regarding the safe use of disinfectants in Jordan and UAE.

METHODS

The study was conducted between October 2022 and June 2023 via an online questionnaire. Data of respondents from Jordan (n = 828) and UAE (n = 619) were analyzed using SPSS. ANOVA, Mann-Whitney, and Kruskal-Wallis tests evaluated significant differences in awareness and performance levels across different demographic groups in Jordan/UAE and between them. Spearman's correlation test examined the correlation between awareness and performance among respondents. Multinomial logistic regression analysis explored associations between various variables and awareness/performance levels within each population.

RESULTS

Findings reveal weak awareness (72.4% and 9.03% in UAE and Jordan, respectively) and moderate performance level (98.8% in UAE and Jordan), with a weak correlation (UAE, rho = 0.093; Jordan, rho = 0.164) observed between the two countries (P < 0.05). Multinomial logistic regression analysis indicates gender-related associations with awareness levels and education-related associations with performance levels.

CONCLUSIONS

The study emphasizes the urgent need for awareness campaigns and workshops to promote safer disinfectant practices to develop effective interventions aligning with sustainable development goals.

Building parameters linked with indoor transmission of SARS-CoV-2

The rapid spread of Coronavirus Disease 2019 (COVID-19), caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), has emphasized the importance of understanding and adapting to the indoor remediation of transmissible diseases to decrease the risk for future pandemic threats. While there were many precautions in place to hinder the spread of COVID-19, there has also been a substantial increase of new research on SARS-CoV-2 that can be utilized to further mitigate the transmission risk of this novel virus. This review paper aims to identify the building parameters of indoor spaces that could have considerable influence on the transmission of SARS-CoV-2. The following building parameters have been identified and analyzed, emphasizing their link with the indoor transmission of SARS-CoV-2: temperature and relative humidity, temperature differences between rooms, ventilation rate and access to natural ventilation, occupant density, surface type and finish, airflow direction and speed, air stability, indoor air pollution, central air conditioning systems, capacity of air handling system and HVAC filter efficiency, edge sealing of air filters, room layout and interior design, and compartmentalization of interior space. This paper also explains the interactions of SARS-CoV-2 with indoor environments and its persistence. Furthermore, the modifications of the key building parameters have been discussed for controlling the transmission of SARS-CoV-2 in indoor spaces. Understanding the information provided in this paper is crucial to develop effective health and safety measures that will aid in infection prevention.

Environmental dissemination of respiratory viruses: dynamic interdependencies of respiratory droplets, aerosols, aerial particulates, environmental surfaces, and contribution of viral re-aerosolization

During the recent pandemic of COVID-19 (SARS-CoV-2), influential public health agencies such as the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC) have favored the view that SARS CoV-2 spreads predominantly via droplets. Many experts in aerobiology have openly opposed that stance, forcing a vigorous debate on the topic. In this review, we discuss the various proposed modes of viral transmission, stressing the interdependencies between droplet, aerosol, and fomite spread. Relative humidity and temperature prevailing determine the rates at which respiratory aerosols and droplets emitted from an expiratory event (sneezing, coughing, etc.) evaporate to form smaller droplets or aerosols, or experience hygroscopic growth. Gravitational settling of droplets may result in contamination of environmental surfaces (fomites). Depending upon human, animal and mechanical activities in the occupied space indoors, viruses deposited on environmental surfaces may be re-aerosolized (re-suspended) to contribute to aerosols, and can be conveyed on aerial particulate matter such as dust and allergens. The transmission of respiratory viruses may then best be viewed as resulting from dynamic virus spread from infected individuals to susceptible individuals by various physical states of active respiratory emissions, instead of the current paradigm that emphasizes separate dissemination by respiratory droplets, aerosols or by contaminated fomites. To achieve the optimum outcome in terms of risk mitigation and infection prevention and control (IPAC) during seasonal infection peaks, outbreaks, and pandemics, this holistic view emphasizes the importance of dealing with all interdependent transmission modalities, rather than focusing on one modality.

Stability of SARS-CoV-2 on Commercial Aircraft Interior Surfaces with Implications for Effective Control Measures

BACKGROUND

The COVID-19 pandemic from 2019 to 2022 devastated many aspects of life and the economy, with the commercial aviation industry being no exception. One of the major concerns during the pandemic was the degree to which the internal aircraft environment contributed to virus transmission between humans and, in particular, the stability of SARS-CoV-2 on contact surfaces in the aircraft cabin interior.

METHOD

In this study, the stability of various major strains of SARS-CoV-2 on interior aircraft surfaces was evaluated using the TCID50 assessment.

RESULTS

In contrast to terrestrial materials, SARS-CoV-2 was naturally less stable on common contact points in the aircraft interior, and, over a 4 h time period, there was a 90% reduction in culturable virus. Antiviral and surface coatings were extremely effective at mitigating the persistence of the virus on surfaces; however, their benefit was diminished by regular cleaning and were ineffective after 56 days of regular use and cleaning. Finally, successive strains of SARS-CoV-2 have not evolved to be more resilient to survival on aircraft surfaces.

CONCLUSIONS

We conclude that the mitigation strategies for SARS-CoV-2 on interior aircraft surfaces are more than sufficient, and epidemiological evidence over the past three years has not found that surface spread is a major route of transmission.

Evaluation of awareness and performance towards COVID-related disinfectant use among the university communities in Lebanon

BACKGROUND

The fast spread of COVID-19 reinforced the daily use of disinfectants around the world. However, the awareness gap of disinfectant use could lead to health risks during the prevention of the pandemic. This study aims to assess the level of awareness and performance towards COVID-related disinfectant use among various university communities (student, staff, and faculty) in Lebanon.

METHODS

A cross-sectional study was conducted between December 2021 and June 2022 among 925 participants (males and females aged between 18 and 64 years old) from academic settings in Lebanese universities using convenience sampling. An online validated survey (score-based questionnaire) of personal disinfectants' utilization was conducted to evaluate the awareness and performance levels using SPSS (version 21). Mann-Whitney and Kruskal-Wallis tests were used to check significant differences in awareness and performance levels among gender, age, provinces, educational level, university status, and field of study. Friedman test was used to test for significant differences in performance level questions pre-and post-COVID-19. The Spearman correlation test was used to determine the correlation between the awareness and performance of the respondents regarding the use of disinfectants.

RESULTS

It was found that the majority of the respondents showed a weak level of awareness (70.8%) while their performance (61.9%) was moderate. Spearman's correlation analysis concluded a weak correlation between the awareness and performance levels (p < 0.01). The Mann-Whitney test indicated that there was a significant difference (p < 0.05) in awareness and performance levels between males and females. Another notable variable was the educational level of the respondents (p < 0.05) with postgraduate degrees holders recording higher mean scores of awareness than the ones with undergraduate and high school degrees as per Kruskal-Wallis test. Significant differences were shown in awareness scores among the age groups and in performance scores among the field of study (p < 0.05).

CONCLUSIONS

The study findings highlighted the necessity of awareness campaigns and training programs addressing the technical handling of disinfectants among the communities in Lebanon. Lebanese governmental authorities (Ministry of Public Health, MoPH, and Ministry of Education and Higher Education, MEHE), and the healthcare professionals and public health researchers in Lebanon may utilize this new evidence to initiate public health interventions as a part of the United Nations (UN) sustainability goal of wellbeing (Sustainable Development Goal 3, SDG 3).

SARS-CoV-2 Survival on Surfaces. Measurements Optimisation for an Enthalpy-Based Assessment of the Risk

The present work, based on the results found in the literature, yields a consistent model of SARS-CoV-2 survival on surfaces as environmental conditions, such as temperature and relative humidity, change simultaneously. The Enthalpy method, which has recently been successfully proposed to investigate the viability of airborne viruses using a holistic approach, is found to allow us to take a reasoned reading of the data available on surfaces in the literature. This leads us to identify the domain of conditions of lowest SARS-CoV-2 viability, in a specific enthalpy range between 50 and 60 kJ/Kg_dry-air. This range appears well-superimposed with the results we previously obtained from analyses of coronaviruses' behaviour in aerosols, and may be helpful in dealing with the spread of infections. To steer future investigations, shortcomings and weaknesses emerging from the assessment of viral measurement usually carried out on surfaces are also discussed in detail. Once demonstrated that current laboratory procedures suffer from both high variability and poor standardisation, targeted implementations of standards and improvement of protocols for future investigations are then proposed.

Viability of SARS-CoV-2 on lettuce, chicken, and salmon and its inactivation by peracetic acid, ethanol, and chlorine dioxide

Since the first SARS-CoV-2 outbreak in Wuhan, China, there has been continued concern over the link between SARS-CoV-2 transmission and food. However, there are few studies on the viability and removal of SARS-CoV-2 contaminating food. This study aimed to evaluate the viability of SARS-CoV-2 on food matrices, depending on storage temperature, and inactivate the virus contaminating food using disinfectants. Two SARS-CoV-2 strains (L and S types) were used to contaminate lettuce, chicken, and salmon, which were then stored at 20,4 and -40 °C. The half-life of SARS-CoV-2 at 20 °C was 3-7 h but increased to 24-46 h at 4 °C and exceeded 100 h at -40 °C. SARS-CoV-2 persisted longer on chicken or salmon than on lettuce. Treatment with 70% ethanol for 1 min inactivated 3.25 log reduction of SARS-CoV-2 inoculated on lettuce but not on chicken and salmon. ClO2 inactivated up to 2 log reduction of SARS-CoV-2 on foods. Peracetic acid was able to eliminate SARS-CoV-2 from all foods. The virucidal effect of all disinfectants used in this study did not differ between the two SARS-CoV-2 strains; therefore, they could also be effective against other SARS-CoV-2 variants. This study demonstrated that the viability of SARS-CoV-2 can be extended at 4 and -40 °C and peracetic acid can inactivate SARS-CoV-2 on food matrices.

Infection control strategies for healthcare workers during COVID-19 pandemic in German hospitals: A cross-sectional study in march-april 2021

Background

Healthcare workers (HCW) are at risk of getting infected with COVID-19 at work. To prevent such incidents and provide a safe environment in hospitals, comprehensive infection control strategies are necessary. We aimed to collect information on COVID-19 infection control strategies regarding personal protective equipment (PPE), regulations during breaks for HCW and dissemination of pandemic-related information.

Methods

We invited infection control practitioners from 987 randomly selected German hospitals in March-April 2021 to participate in our cross-sectional online survey. We categorized the hospital based on bed capacity (≤499 beds = small; ≥500 beds = large). Fisher's exact test was performed and p < 0.05 defined as statistically significant.

Findings

100 participants completed the questionnaire. Small hospitals were more directive about requiring FFP2 respirators (63%), whereas larger hospitals more often gave their HCW a choice between these and medical masks (67%). For the care of COVID-19 and suspected COVID-19 cases, >90% of the participants recommended the use of gloves. Notably, gloves were recommended beyond COVID-19 in 30% of the hospitals. During meal breaks various strategies were followed.

Conclusion

Recommendations for PPE varied across hospital sizes, which could be due to different assessments of necessity and safety. Regulations during breaks varied strongly which illustrates the need for clear official guidelines.

Efficacy of copper blend coatings in reducing SARS-CoV-2 contamination

SARS-CoV-2 is a highly infectious virus and etiologic agent of COVID-19, which is spread by respiratory droplets, aerosols, and contaminated surfaces. Copper is a known antiviral agent, and has resulted in successful reduction of pathogens and infections by 83-99.9% when coated on surfaces in intensive care units. Additionally, copper has been shown to inactivate pathogens such as Coronavirus 226E, a close relative of SARS-CoV-2. Here, we examine the ability of two copper blends with differing compositions to inactivate SARS-CoV-2 virus at different time points. Copper Blend 2 (75.07% pure copper) was found to significantly reduce (over 50%) the viability of SARS-CoV-2 at 5 min of contact, with at least 98% reduction in recovered virus at 20 min (vs. plastic control). However, Copper Blend 1 (48.26% pure copper), was not found to significantly reduce viability of SARS-CoV-2 at any time point when compared to plastic. This may indicate that there is an important percentage of copper content in materials that is needed to effectively inactivate SARS-CoV-2. Overall, this study shows that over the course of 20 min, coatings made of copper materials can significantly reduce the recovery of infectious SARS-CoV-2 compared to uncoated controls, indicating the effective use of copper for viral inactivation on surfaces. Furthermore, it may suggest higher copper content has stronger antiviral properties. This could have important implications when short turnaround times are needed for cleaning and disinfecting rooms or equipment, especially in strained healthcare settings which are struggling to keep up with demand.

COVID-19 prevalence and infection control practices among dentists in Andhra Pradesh State, India

BACKGROUND

The coronavirus 2019 (COVID-19) pandemic posed a new challenge not only to public health but also to the health care systems and dentists are one of the highly vulnerable health care professionals for COVID-19 infection.

OBJECTIVE

To assess the COVID-19 prevalence, associated factors, and infection control practices among dentists in Andhra Pradesh State, IndiaMETHODS:A cross-sectional web-based questionnaire survey was conducted among dentists in Andhra Pradesh state, India. 21-item pretested questionnaire was used for data collection between January 30, 2021 and February 21, 2021. 3700 dentists from the Andhra Pradesh state were selected from the Dentists Register of India through systematic random sampling method.

RESULTS

Out of 3700 dentists invited to participate in this study, responses from 1876 dentists were received with response rate of 51%. Prevalence of 8 among the study population was 9%. Patients were the primary source of infection for 60.5% of the COVID-19 positive study participants. 65.8% of total respondents using full face shield and two-third of them using N-95 or equivalent mask while providing dental care.

CONCLUSION

This study found a high prevalence rate of COVID 19 among the dentists. Among the associated factors, being into active practice during the pandemic was found to be statistically significant. This study recommend for additional infection control protocols specific to the COVID-19 pandemic.

Exploring the Impact and Prevention of Epidemics from a New Perspective: COVID-19 Transmission through Express Boxes

The number of express boxes worldwide exceeded 170 billion in 2021, and, from several regions in China, tested positive. Therefore, it is important to study the transmission of viruses through express boxes. In this paper, we establish a model of express box virus transmission based on comprehensive consideration of environmental factors, such as temperature, disinfection, humidity, virus release intensity, and volume of vehicle, to study the transmission of express box virus, and explore the spatial and geographic spread variation of express box viruses in China. Several important findings emerged from the study, including: (1) Disinfection can prolong the spread of viruses in the express box for ≥21 h; (2) For every 1 °C rise in temperature, the infected time can be prolonged by ≥1.2 h, and for every 10% rise in relative humidity, the virus transmission time can be prolonged by ≥1.32 h; (3) In an environment suitable for virus transmission, when loaded with 1000, 2000, 4000 express boxes, areas where the express delivery time exceeds 22.56, 18, 14.64 h will face the risk of all the boxes in the carriage being infected. These findings could help public health departments prevent the risk of virus transmission from express boxes.

Antimicrobial properties of a multi-component alloy

High traffic touch surfaces such as doorknobs, countertops, and handrails can be transmission points for the spread of pathogens, emphasizing the need to develop materials that actively self-sanitize. Metals are frequently used for these surfaces due to their durability, but many metals also possess antimicrobial properties which function through a variety of mechanisms. This work investigates metallic alloys comprised of several metals which individually possess antimicrobial properties, with the target of achieving broad-spectrum, rapid sanitation through synergistic activity. An entropy-motivated stabilization paradigm is proposed to prepare scalable alloys of copper, silver, nickel and cobalt. Using combinatorial sputtering, thin-film alloys were prepared on 100 mm wafers with ≈50% compositional grading of each element across the wafer. The films were then annealed and investigated for alloy stability. Antimicrobial activity testing was performed on both the as-grown alloys and the annealed films using four microorganisms-Phi6, MS2, Bacillus subtilis and Escherichia coli-as surrogates for human viral and bacterial pathogens. Testing showed that after 30 s of contact with some of the test alloys, Phi6, an enveloped, single-stranded RNA bacteriophage that serves as a SARS-CoV-2 surrogate, was reduced up to 6.9 orders of magnitude (> 99.9999%). Additionally, the non-enveloped, double-stranded DNA bacteriophage MS2, and the Gram-negative E. coli and Gram-positive B. subtilis bacterial strains showed a 5.0, 6.4, and 5.7 log reduction in activity after 30, 20 and 10 min, respectively. Antimicrobial activity in the alloy samples showed a strong dependence on the composition, with the log reduction scaling directly with the Cu content. Concentration of Cu by phase separation after annealing improved activity in some of the samples. The results motivate a variety of themes which can be leveraged to design ideal antimicrobial surfaces.

Nanomaterials to combat SARS-CoV-2: Strategies to prevent, diagnose and treat COVID-19

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection and the associated coronavirus disease 2019 (COVID-19), which severely affect the respiratory system and several organs and tissues, and may lead to death, have shown how science can respond when challenged by a global emergency, offering as a response a myriad of rapid technological developments. Development of vaccines at lightning speed is one of them. SARS-CoV-2 outbreaks have stressed healthcare systems, questioning patients care by using standard non-adapted therapies and diagnostic tools. In this scenario, nanotechnology has offered new tools, techniques and opportunities for prevention, for rapid, accurate and sensitive diagnosis and treatment of COVID-19. In this review, we focus on the nanotechnological applications and nano-based materials (i.e., personal protective equipment) to combat SARS-CoV-2 transmission, infection, organ damage and for the development of new tools for virosurveillance, diagnose and immune protection by mRNA and other nano-based vaccines. All the nano-based developed tools have allowed a historical, unprecedented, real time epidemiological surveillance and diagnosis of SARS-CoV-2 infection, at community and international levels. The nano-based technology has help to predict and detect how this Sarbecovirus is mutating and the severity of the associated COVID-19 disease, thereby assisting the administration and public health services to make decisions and measures for preparedness against the emerging variants of SARS-CoV-2 and severe or lethal COVID-19.

Zebrafish models of COVID-19

Although COVID-19 has only recently appeared, research studies have already developed and implemented many animal models for deciphering the secrets of the disease and provided insights into the biology of SARS-CoV-2. However, there are several major factors that complicate the study of this virus in model organisms, such as the poor infectivity of clinical isolates of SARS-CoV-2 in some model species, and the absence of persistent infection, immunopathology, severe acute respiratory distress syndrome, and, in general, all the systemic complications which characterize COVID-19 clinically. Another important limitation is that SARS-CoV-2 mainly causes severe COVID-19 in older people with comorbidities, which represents a serious problem when attempting to use young and immunologically naïve laboratory animals in COVID-19 testing. We review here the main animal models developed so far to study COVID-19 and the unique advantages of the zebrafish model that may help to contribute to understand this disease, in particular to the identification and repurposing of drugs to treat COVID-19, to reveal the mechanism of action and side-effects of Spike-based vaccines, and to decipher the high susceptibility of aged people to COVID-19.

Indirect Virus Transmission via Fomites Can Counteract Lock-Down Effectiveness

The spread of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) has raised major health policy questions. Direct transmission via respiratory droplets seems to be the dominant route of its transmission. However, indirect transmission via shared contact of contaminated objects may also occur. The contribution of each transmission route to epidemic spread might change during lock-down scenarios. Here, we simulate viral spread of an abstract epidemic considering both routes of transmission by use of a stochastic, agent-based SEIR model. We show that efficient contact tracing (CT) at a high level of incidence can stabilize daily cases independently of the transmission route long before effects of herd immunity become relevant. CT efficacy depends on the fraction of cases that do not show symptoms. Combining CT with lock-down scenarios that reduce agent mobility lowers the incidence for exclusive direct transmission scenarios and can even eradicate the epidemic. However, even for small fractions of indirect transmission, such lockdowns can impede CT efficacy and increase case numbers. These counterproductive effects can be reduced by applying measures that favor distancing over reduced mobility. In summary, we show that the efficacy of lock-downs depends on the transmission route. Our results point to the particular importance of hygiene measures during mobility lock-downs.

The Lesson Learned from the COVID-19 Pandemic: Can an Active Chemical Be Effective, Safe, Harmless-for-Humans and Low-Cost at a Time? Evidence on Aerosolized Hypochlorous Acid

The COVID-19 pandemic has underlined the importance of disinfectants as tools to prevent and fight against coronavirus spreading. An ideal disinfectant and sanitizer must be nontoxic to surface contact, noncorrosive, effective, and relatively inexpensive as it is hypochlorous acid (HOCl). The present work intended to evaluate, on different surfaces, the bactericidal and virucidal effectiveness of nebulized HOCl and test its safety usage in 2D and 3D skin and lung models. Our data showed that HOCl at the dose of 300 ppm did not affect cellular and tissue viability, not their morphology. The HOCl bactericidal properties varies with the surface analyzed: 69% for semi-porous, 96-99.9% for flat and porous. This discrepancy was not noticed for the virucidal properties. Overall, this study showed that nebulized HOCl can prevent virus and bacteria growth without affecting lung and skin tissues, making this compound a perfect candidate to sanitize indoor environments.

Potent Inactivation of Human Respiratory Viruses Including SARS-CoV-2 by a Photoactivated Self-Cleaning Regenerative Antiviral Coating

The COVID-19 pandemic marks an inflection point in the perception and treatment of human health. Substantial resources have been reallocated to address the direct medical effects of COVID-19 and to curtail the spread of the virus. Thereby, shortcomings of traditional disinfectants, especially their requirement for regular reapplication and the related complications (e.g., dedicated personnel and short-term activity), have become issues at the forefront of public health concerns. This issue became especially pressing when infection-mitigating supplies dwindled early in the progression of the pandemic. In consideration of the constant threat posed by emerging novel viruses, we report a platform technology for persistent surface disinfection to combat virus transmission through nanomaterial-mediated, localized UV radiation emission. In this work, two formulations of Y2SiO5-based visible-to-UV upconversion nanomaterials were developed using a facile sol-gel-based synthesis. Our formulations have shown substantial antiviral activities (4 × 104 to 0 TCID50 units in 30 min) toward an enveloped, circulating human coronavirus strain (OC43) under simple white light exposure as an analogue to natural light or common indoor lighting. Additionally, we have shown that our two formulations greatly reduce OC43 RNA recovery from surfaces. Antiviral activities were further demonstrated toward a panel of structurally diverse viruses including enveloped viruses, SARS-CoV-2, vaccinia virus, vesicular stomatitis virus, parainfluenza virus, and Zika virus, as well as nonenveloped viruses, rhinovirus, and calicivirus, as evidence of the technology's broad antiviral activity. Remarkably, one formulation completely inactivated 105 infectious units of SARS-CoV-2 in only 45 min. The detailed technology has implications for the design of more potent, long-lived disinfectants and modified/surface-treated personal protective equipment targeting a wide range of viruses.

Assessment of Surface Disinfection Effectiveness of Decontamination System COUNTERFOG® SDR-F05A+ Against Bacteriophage ɸ29

The experience of COVID19 pandemic has demonstrated the real concern of biological agents dispersed in the air and surfaces environments. Therefore, the need of a fast and large-scale disinfection method has arisen for prevention of contagion. COUNTERFOG® is an innovative technology developed for large-scale decontamination of air and surfaces. The objective of this study is to assess experimentally the effectiveness of COUNTERFOG® in disinfecting viral-contaminated surfaces. We also aim to measure the necessary time to disinfect said surfaces. Stainless steel surfaces were contaminated with bacteriophage φ29 and disinfected using COUNTERFOG® SDR-F05A+, which uses a sodium hypochlorite solution at different concentrations and for different exposure times. A log reduction over 6 logs of virus titer is obtained in 1 min with 1.2% sodium hypochlorite when the application is direct; while at a radial distance of 5 cm from the point of application the disinfection reaches a reduction of 5.5 logs in 8 min. In the same way, a higher dilution of the sodium hypochlorite concentration (0.7% NaOCl) requires more exposure time (16 min) to obtain the same log reduction (> 6 logs). COUNTERFOG® creates, in a short time and at a distance of 2 m from the point of application, a thin layer of disinfectant that covers the surfaces. The selection of the concentration and exposure time is critical for the efficacy of disinfection. These tests demonstrate that a concentration between 0.7- 1.2% sodium hypochlorite is enough for a fast and efficient ɸ29 phage inactivation. The fact that ɸ29 phage is more resistant to disinfection than SARS-CoV-2 sustains this disinfection procedure.

No Evidence of SARS-CoV-2 Among Flies or Cockroaches in Households Where COVID-19 Positive Cases Resided

Flies and other arthropods mechanically transmit multiple pathogens and a recent experimental study demonstrated house flies, Musca domestica L. (Diptera: Muscidae), can mechanically transmit SARS-CoV-2. The purpose of this study was to explore the possibility of mechanical transmission of SARS-CoV-2 by domestic insects and their potential as a xenosurveillance tool for detection of the virus. Flies were trapped in homes where at least one confirmed human COVID-19 case(s) resided using sticky and liquid-baited fly traps placed inside and outside the home in the Texas counties of Brazos, Bell, and Montgomery, from June to September 2020. Flies from sticky traps were identified, pooled by taxa, homogenized, and tested for the presence of SARS-CoV-2 RNA using quantitative reverse transcription PCR (RT-qPCR). Liquid traps were drained, and the collected fluid similarly tested after RNA concentration. We processed the contents of 133 insect traps from 40 homes, which contained over 1,345 individual insects of 11 different Diptera families and Blattodea. These individuals were grouped into 243 pools, and all tested negative for SARS-CoV-2 RNA. Fourteen traps in seven homes were deployed on the day that cat or dog samples tested positive for SARS-CoV-2 RNA by nasal, oral, body, or rectal samples. This study presents evidence that biting and nonbiting flies and cockroaches (Blattodea) are not likely to contribute to mechanical transmission of SARS-CoV-2 or be useful in xenosurveillance for SARS-CoV-2.

Electrostatic Spray Disinfection Using Nano-Engineered Solution on Frequently Touched Surfaces in Indoor and Outdoor Environments

The COVID-19 pandemic has resulted in high demand for disinfection technologies. However, the corresponding spray technologies are still not completely optimized for disinfection purposes. There are important problems, like the irregular coverage and dripping of disinfectant solutions on hard and vertical surfaces. In this study, we highlight two major points. Firstly, we discuss the effectiveness of the electrostatic spray deposition (ESD) of nanoparticle-based disinfectant solutions for systematic and long-lasting disinfection. Secondly, we show that, based on the type of material of the substrate, the effectiveness of ESD varies. Accordingly, 12 frequently touched surface materials were sprayed using a range of electrostatic spray system parameters, including ion generator voltage, nozzle spray size and distance of spray. It was observed that for most cases, the surfaces become completely covered with the nanoparticles within 10 s. Acrylic, Teflon, PVC, and polypropylene surfaces show a distinct effect of ESD and non-ESD sprays. The nanoparticles form a uniform layer with better surface coverage in case of electrostatic deposition. Quantitative variations and correlations show that 1.5 feet of working distance, an 80 μm spray nozzle diameter and an ion generator voltage of 3-7 kV ensures a DEF (differential electric field) that corresponds to an optimized charge-to-mass ratio, ensuring efficient coverage of nanoparticles.

Decontamination of SARS-CoV-2 from cold-chain food packaging provides no marginal benefit in risk reduction to food workers

Countries continue to debate the need for decontamination of cold-chain food packaging to reduce possible severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) fomite transmission among frontline workers. While laboratory-based studies demonstrate persistence of SARS-CoV-2 on surfaces, the likelihood of fomite-mediated transmission under real-life conditions is uncertain. Using a quantitative microbial risk assessment model of a frozen food packaging facility, we simulated 1) SARS-CoV-2 fomite-mediated infection risks following worker exposure to contaminated plastic packaging; and 2) reductions in these risks from masking, handwashing, and vaccination. In a frozen food facility without interventions, SARS-CoV-2 infection risk to a susceptible worker from contact with contaminated packaging was 1.5 × 10^-3 per 1h-period (5th - 95th percentile: 9.2 × 10^-6, 1.2 × 10^-2). Standard food industry infection control interventions, handwashing and masking, reduced risk (99.4%) to 8.5 × 10^-6 risk per 1h-period (5th - 95th percentile: 2.8 × 10^-8, 6.6 × 10^-5). Vaccination of the susceptible worker (two doses Pfizer/Moderna, vaccine effectiveness: 86-99%) with handwashing and masking reduced risk to 5.2 × 10^-7 risk per 1h-period (5th - 95th percentile: 1.8 × 10^-9, 5.4 × 10^-6). Simulating increased transmissibility of current and future variants (Delta, Omicron), (2-, 10-fold viral shedding) among a fully vaccinated workforce, handwashing and masking continued to mitigate risk (1.4 × 10^-6 - 8.8 × 10^-6 risk per 1h-period). Additional decontamination of frozen food plastic packaging reduced infection risks to 1.2 × 10^-8 risk per 1h-period (5th - 95th percentile: 1.9 × 10^-11, 9.5 × 10^-8). Given that standard infection control interventions reduced risks well below 1 × 10^-4 (World Health Organization water quality risk thresholds), additional packaging decontamination suggest no marginal benefit in risk reduction. Consequences of this decontamination may include increased chemical exposures to workers, food quality and hazard risks to consumers, and unnecessary added costs to governments and the global food industry.

Green aspects of photocatalysts during corona pandemic: a promising role for the deactivation of COVID-19 virus

The selection of a facile, eco-friendly, and effective methodology is the need of the hour for efficient curing of the COVID-19 virus in air, water, and many food products. Recently, semiconductor-based photocatalytic methodologies have provided promising, green, and sustainable approaches to battle against viral activation via the oxidative capabilities of various photocatalysts with excellent performance under moderate conditions and negligible by-products generation as well. Considering this, recent advances in photocatalysis for combating the spread of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) are inclusively highlighted. Starting from the origin to the introduction of the coronavirus, the significant potential of photocatalysis against viral prevention and -disinfection is discussed thoroughly. Various photocatalytic material-based systems including metal-oxides, metal-free and advanced 2D materials (MXenes, MOFs and COFs) are systematically examined to understand the mechanistic insights of virus-disinfection in the human body to fight against COVID-19 disease. Also, a roadmap toward sustainable solutions for ongoing COVID-19 contagion is also presented. Finally, the challenges in this field and future perspectives are comprehensively discussed involving the bottlenecks of current photocatalytic systems along with potential recommendations to deal with upcoming pandemic situations in the future.

Virucidal Properties of Photocatalytic Coating on Glass against a Model Human Coronavirus

The antimicrobial properties of photocatalysts have long been studied. However, most of the available literature describes their antibacterial properties, while knowledge of their antiviral activity is rather scarce. Since the outset of the coronavirus disease 2019 (COVID-19) pandemic, an increasing body of research has suggested their antiviral potential and highlighted the need for further research in this area. In this study, we investigated the virucidal properties of a commercial TiO₂-coated photocatalytic glass against a model human coronavirus. Our findings demonstrate that the TiO₂-coated glass consistently inactivates coronaviruses upon contact under daylight illumination, in a time-dependent manner. A 99% drop in virus titer was achieved after 3.9 h. The electron micrographs of virus-covered TiO₂-glass showed a reduced number of virions compared to control glass. Morphological alterations of TiO₂-exposed viruses included deformation, disruption of the viral envelope, and virion ghosts, endorsing the application of this material in the construction of protective elements to mitigate the transmission of viruses. To the best of our knowledge, this is the first report showing direct visual evidence of human coronaviruses being damaged and morphologically altered following exposure to this photocatalyst.

IMPORTANCE Surface contamination is an important contributor to SARS-CoV-2 spread. The use of personal protective elements and physical barriers (i.e., masks, gloves, and indoor glass separators) increases safety and has proven invaluable in preventing contagion. Redesigning these barriers so that the virus cannot remain infectious on them could make a difference in COVID-19 epidemiology. The introduction of additives with virucidal activity could potentiate the protective effects of these barriers to serve not only as physical containment but also as virus killers, reducing surface contamination after hand touch or aerosol deposition. We performed in-depth analysis of the kinetics of photocatalysis-triggered coronavirus inactivation on building glass coated with TiO₂. This is the first report showing direct visual evidence (electron microscopy) of coronaviruses being morphologically damaged following exposure to this photocatalyst, demonstrating the high potential of this material to be incorporated into daily-life high-touch surfaces, giving them an added value in decelerating the virus spread.

Survival of SARS-CoV-2 in artificial seawater and on the surface of inanimate materials

There is a potential risk for severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) spread through human contact with seafood and the inanimate materials contaminated by the virus. In this study, we examined the stability of the virus in artificial seawater (ASW) and on the surface of selected materials. SARS‐CoV‐2 (3.75 log₁₀ TCID₅₀) in ASW at 22℃ maintained infectious about 3 days and at 4℃ the virus survived more than 7 days. It should be noticed that viable virus at high titer (5.50 log₁₀ TCID₅₀) may survive more than 20 days in ASW at 4℃ and for 7 days at 22℃. SARS‐CoV‐2 on stainless steel and plastic bag maintained infectious for 3 days, and on nonwoven fabric for 1 day at 22℃. In addition, the virus remained infectious for 9 days on stainless steel and non‐woven fabric, and on plastic bag for 12 days at 4℃. It is important to highlight the role of inanimate material surfaces as a source of infection and the necessity for surface decontamination and disinfection.

Coronaviruses are stable on glass, but are eliminated by manual dishwashing procedures

Severe acute respiratory syndrome coronavirus type 2 (SARS-CoV-2) is primarily transmitted from human to human via droplets and aerosols. While transmission via contaminated surfaces is also considered possible, the overall risk of this transmission route is assumed to be low. Nevertheless, transmission through contaminated drinking glasses may pose an increased risk as the glass is in direct contact with the mouth and oral cavity. Using human coronavirus 229E (HCoV-229E) as surrogate for SARS-CoV-2, this study examined coronavirus stability on glass, inactivation by dishwashing detergents, and virus elimination by a manual glass scrubbing device. Infectious HCoV-229E was recovered from glass for 7 and 21 days of storage under daylight and dark conditions, respectively. Near complete inactivation of HCoV-229E (>4 log₁₀ reduction) was observed after incubation with two common dishwashing detergents at room temperature for 15 s, whereas incubation at 43 °C for 60 s was necessary for a third detergent to achieve a similar titer reduction. The virus was efficiently removed from contaminated drinking glasses using a manual glass scrubbing device in accordance with German standard DIN 6653-3. The results confirm that coronaviruses are relatively stable on glass, but indicate that common manual dishwashing procedures can efficiently eliminate coronaviruses from drinking glasses.

SARS-CoV-2 cold-chain transmission: Characteristics, risks and strategies

Low temperature and certain humidity are conducive to severe acute respiratory syndrome coronavirus 2 (SARS‐CoV‐2) for long‐time survival and long‐distance spread during logistics and trades. Contaminated cold‐chain or frozen products and outer packaging act as the carrier of SARS‐CoV‐2, that infects the high‐risk population who works in the ports, cold storage or seafood market. Since the coronavirus disease 2019 (COVID‐19) pandemic worldwide, multiple localized outbreaks caused by SARS‐CoV‐2 contaminated imported cold‐chain products have been reported in China, which brought challenges to COVID‐19 prevention and control. Here, we review the evidences of SARS‐CoV‐2 cold‐chain transmission from six confirmed cold‐chain related COVID‐19 outbreaks in China, especially in terms of SARS‐CoV‐2 whole‐genome sequencing and virus isolation. In addition, we summarize the characteristics and mode of SARS‐CoV‐2 cold‐chain transmission from both six COVID‐19 outbreaks in China and the outbreaks suspected cold‐chain transmission in other countries. Finally, we analyze the underlying risks of SARS‐CoV‐2 cold‐chain transmission and propose the preventive countermeasures.

SARS‐CoV‐2 contaminated cold‐chain products can infect high‐risk populations and subsequently cause community transmission

Specific locations, such as seafood market stalls, can amplify outbreaks

Cold‐chain fomites accelerate global spread of SARS‐CoV‐2 and cause “silent transmission”

Rational sampling, comprehensive disinfection, protection of high‐risk groups and pollution classification are the main strategies

The Impact of COVID-19 Pandemic on Halting Sustainable Development in the Colca y Volcanes de Andagua UNESCO Global Geopark in Peru—Prospects and Future

Events, such as the COVID-19 pandemic, that rapidly impact global communication and travel have significant consequences for the tourism industry, which is one of the pillars of global development. We assess the impacts of the COVID-19 crisis on the Colca y Volcanes de Andagua UNESCO Global Geopark in Peru. The Colca y Volcanes de Andagua Geopark was established immediately prior to the pandemic in October 2019. The instability of the government in Peru during the pandemic and the difficult living conditions in the high Andes, such as the lack of drinking water, cleaning agents, medical care, and the high levels of poverty, particularly in the geopark region, has contributed to the significantly high COVID-19 infection rates. In addition, detrimental impacts faced by the local community are a direct result of a reduction in travellers to the area due to legislative restrictions, which have had negative consequences on the local tourism industry. There is an urgent need for the recovery of the local tourism industry to prevent the permanent closure of tourism facilities and to minimise poverty rates.

Wastewater, waste, and water-based epidemiology (WWW-BE): A novel hypothesis and decision-support tool to unravel COVID-19 in low-income settings?

Traditional wastewater-based epidemiology (W-BE) relying on SARS-CoV-2 RNA detection in wastewater is attractive for understanding COVID-19. Yet traditional W-BE based on centralized wastewaters excludes putative SARS-CoV-2 reservoirs such as: (i) wastewaters from shared on-site sanitation facilities, (ii) solid waste including faecal sludge from non-flushing on-site sanitation systems, and COVID-19 personal protective equipment (PPE), (iii) raw/untreated water, and (iv) drinking water supply systems in low-income countries (LICs). A novel hypothesis and decision-support tool based on Wastewater (on-site sanitation, municipal sewer systems), solid Waste, and raw/untreated and drinking Water-based epidemiology (WWW-BE) is proposed for understanding COVID-19 in LICs. The WWW-BE conceptual framework, including components and principles is presented. Evidence on the presence of SARS-CoV-2 and its proxies in wastewaters, solid materials/waste (papers, metals, fabric, plastics), and raw/untreated surface water, groundwater and drinking water is discussed. Taken together, wastewaters from municipal sewer and on-site sanitation systems, solid waste such as faecal sludge and COVID-19 PPE, raw/untreated surface water and groundwater, and drinking water systems in LICs act as potential reservoirs that receive and harbour SARS-CoV-2, and then transmit it to humans. Hence, WWW-BE could serve a dual function in estimating the prevalence and potential transmission of COVID-19. Several applications of WWW-BE as a hypothesis and decision support tool in LICs are discussed. WWW-BE aggregates data from various infected persons in a spatial unit, hence, putatively requires less resources (analytical kits, personnel) than individual diagnostic testing, making it an ideal decision-support tool for LICs. The novelty, and a critique of WWW-BE versus traditional W-BE are presented. Potential challenges of WWW-BE include: (i) biohazards and biosafety risks, (ii) lack of expertise, analytical equipment, and accredited laboratories, and (iii) high uncertainties in estimates of COVID-19 cases. Future perspectives and research directions including key knowledge gaps and the application of novel and emerging technologies in WWW-BE are discussed.

UltraViolet SANitizing System for Sterilization of Ambulances Fleets and for Real-Time Monitoring of Their Sterilization Level

BACKGROUND

The contamination of ambulances with pathogenic agents represents a potential threat for the public health, not only for common pathogens but also for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The aim of this project was to exploits the germicidal effect of the UVC radiation at 254 nm to sanitize the patient's compartment of ambulances with an advanced UltraViolet SANitizing System (UV-SAN) and assess its relevance for avoiding the spread of COVID-19 and other drug resistant pathogens.

METHODS

The system is equipped with UVC lamps that are activated when the ambulance compartment is empty and sanitize the environment in less than 15 min. An Ozone sensor continuously monitors the gas concentration, ensuring it does not exceed threshold value harmful for patients and operators' health. The system is relying on GNSS data and a satellite communication link, which allow to monitor and record traceability (when, where and what) of all the sanitation operations performed. This information is real-time monitored from a dedicated web-application.

RESULTS

UVC irradiation efficiently reduced SARS-CoV-2 virus titer (>99.99%), on inanimate surfaces such as plastic, stainless steel or rubber, with doses ranging from 5.5 to 24.8 mJ/cm2 and the UV-SAN system is effective against multi drug resistant (MDR) bacteria up to >99.99%, after 10 to 30 min of irradiation.

CONCLUSIONS

UV-SAN can provide rapid, efficient and sustainable sanitization procedures of ambulances.

Drying of virus-containing particles: modelling effects of droplet origin and composition

BACKGROUND AND PURPOSE

Virus-containing aerosol droplets emitted by breathing, speech or coughing dry rapidly to equilibrium with ambient relative humidity (RH), increasing in solute concentration with effects on virus survival and decreasing in diameter with effects on sedimentation and respiratory uptake. The aim of this paper is to model the effect of ionic and macromolecular solutes on droplet drying and solute concentration.

METHODS

Deliquescence-efflorescence concepts and Kohler theory were used to simulate the evolution of solute concentrations and water activity in respiratory droplets, starting from efflorescence data on mixed NaCl/KCl aerosols and osmotic pressure data on respiratory macromolecules.

RESULTS

In NaCl/KCl solutions total salt concentrations were shown to reach 10-13 M at the efflorescence RH of 40-55%, depending on the K:Na ratio. Dependence on K:Na ratio implies that the evaporation curves differ between aerosols derived from saliva and from airway surfaces. The direct effect of liquid droplet size through the Kelvin term was shown to be smaller and restricted to the evolution of breath emissions. Modelling the effect of proteins and glycoproteins showed that salts determine drying equilibria down to the efflorescence RH, and macromolecules at lower RH.

CONCLUSION

Differences in solute composition between airway surfaces and saliva are predicted to lead to different drying behaviour of droplets emitted by breathing, speech and coughing. These differences may influence the inactivation of viruses.

In vitro virucidal efficacy of a dry steam disinfection system against Human Coronavirus, Human Influenza Virus, and Echovirus

This in vitro study was aimed to assess the efficacy of dry steam in inactivating Human Coronavirus OC43 (HCoV-OC43) as surrogate of SARS-CoV-2, Human Influenza Virus A/H1N1/WSN/33 and Echovirus 7 on stainless steel, polypropylene, and cotton. The virus models were chosen on the basis of their transmission route and environmental resistance. Tests were carried out under a laminar flow cabinet, where two panels of each material were contaminated with a viral suspension. The inocula were left to dry and then the virus on untreated panel (control) was collected by swabbing in order to determine the initial titer. The other panel was treated using a professional vacuum cleaner equipped with a dry steam generator. Dry steam is generated in a boiler where tap water is heated up to 155 °C at 5.5 bar pressure and then during the passage along the flexible hose the temperature decreases to a value between 100 °C and 110 °C at the output. The dry steam was applied for four sec with a window wiper on metal and plastic panels or a brush covered by a microfiber cap on cotton, simulating the steam application during routine cleaning. After the treatment, infectious virus possibly remained on the surface was collected following the same swabbing procedure applied for controls. HCoV-OC43 and Echovirus 7 were titrated by end-point method on HCT-8 line cells and Vero cells, respectively, while Human Influenza Virus was quantified by plaque reduction assay on MDCK cells. Dry steam resulted effective against the three viruses on all tested materials, achieving a mean Log₁₀ reduction factor ≥4 in viral titer of treated samples compared with controls according to UNI EN 14476:2019. Thus, dry steam may be proposed as an ease to use, effective, fast, and nontoxic alternative to chemicals for surface disinfection without damaging materials. Therefore, this device could be employed not only in healthcare facilities but also in occupational, domestic, and community settings, with advantages for environment and human health.

Application of Copper Iodide Nanoparticle-Doped Film and Fabric To Inactivate SARS-CoV-2 via the Virucidal Activity of Cuprous Ions (Cu+)

As a result of the novel coronavirus disease 2019 pandemic, strengthening control measures against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has become an urgent global issue. In addition to antiviral therapy and vaccination strategies, applying available virucidal substances for SARS-CoV-2 inactivation is also a target of research to prevent the spread of infection. Here, we evaluated the SARS-CoV-2 inactivation activity of a copper iodide (CuI) nanoparticle dispersion, which provides Cu+ ions having high virucidal activity, and its mode of actions. In addition, the utility of CuI-doped film and fabric for SARS-CoV-2 inactivation was evaluated. The CuI dispersion exhibited time-dependent rapid virucidal activity. Analyses of the modes of action of CuI performed by Western blotting and real-time reverse transcription-PCR targeting viral proteins and the genome revealed that CuI treatment induced the destruction of these viral components. In this setting, the indirect action of CuI-derived reactive oxygen species contributed to the destruction of viral protein. Moreover, the CuI-doped film and fabric demonstrated rapid inactivation of the SARS-CoV-2 solution in which the viral titer was high. These findings indicated the utility of the CuI-doped film and fabric as anti-SARS-CoV-2 materials for the protection of high-touch environmental surfaces and surgical masks/protective clothes. Throughout this study, we demonstrated the effectiveness of CuI nanoparticles for inactivating SARS-CoV-2 and revealed a part of its virucidal mechanism of action. IMPORTANCE The COVID-19 pandemic has caused an unprecedented number of infections and deaths. As the spread of the disease is rapid and the risk of infection is severe, hand and environmental hygiene may contribute to suppressing contact transmission of SARS-CoV-2. Here, we evaluated the SARS-CoV-2 inactivation activity of CuI nanoparticles, which provide the Cu+ ion as an antiviral agent, and we provided advanced findings of the virucidal mechanisms of action of Cu+. Our results showed that the CuI dispersion, as well as CuI-doped film and fabric, rapidly inactivated SARS-CoV-2 with a high viral titer. We also demonstrated the CuI's virucidal mechanisms of action, specifically the destruction of viral proteins and the genome by CuI treatment. Protein destruction largely depended on CuI-derived reactive oxygen species. This study provides novel information about the utility and mechanisms of action of promising virucidal material against SARS-CoV-2.

Risks of Infection with SARS-CoV-2 Due to Contaminated Surfaces: A Scoping Review

The COVID-19 outbreak is a global health concern. Understanding the transmission modes of the SARS-CoV-2 virus is key to limit the spread of the pandemic. A lack of knowledge about the possibility of SARS-CoV-2 transmission and infection through contaminated surfaces is noticeable and recent studies have stated conflicting findings. This scoping review aims to understand the risks of contaminations via fomites better. Relevant publications were selected through Google Scholar, Web of Science, PubMed, Embase, Medline, and Cochrane Library, with related keywords. PRISMA-ScR guidelines were followed. Out of the 565 articles found, exclusion criteria were applied, duplicates removed, and a total of 25 articles were finally included in the study. The included documents were assessed by the contamination risk: "low" (37.5%), "high" (16.7%), "plausible" (8.3%), "unlikely" (8.3%) risk, and "insufficient evidence" (29.2%). Research in hospital settings was found as the main setting in the reviewed papers, which precisely indicated the risk of contaminated surfaces. This scoping review underscores the risk of SARS-CoV-2 infection via contaminated surfaces assessed as low in the majority of the reviewed articles. Further evaluation of the risk of the virus transmission by fomites and providing adequate information on its infectivity via contaminated surfaces in real-life conditions is essential.

Inactivation of SARS-CoV-2 by Simulated Sunlight on Contaminated Surfaces

We studied the stability of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) under different simulated outdoor conditions by changing the temperature (20°C and 35°C), the illuminance (darkness, 10 klx, and 56 klx), and/or the cleanness of the surfaces at 50% relative humidity (RH). In darkness, the loss of viability of the virus on stainless steel is temperature dependent, but this is hidden by the effect of the sunlight from the first minutes of exposure. The virus shows a sensitivity to sunlight proportional to the illuminance intensity of the sunlight. The presence of interfering substances has a moderate effect on virus viability even with an elevated illuminance. Thus, SARS-CoV-2 is rapidly inactivated by simulated sunlight in the presence or absence of high levels of interfering substances at 20°C or 35°C and 50% relative humidity. IMPORTANCE Clinical matrix contains high levels of interfering substances. This study is the first to reveal that the presence of high levels of interfering substances had little impact on the persistence of SARS-CoV-2 on stainless steel following exposure to simulated sunlight. Thus, SARS-CoV-2 should be rapidly inactivated in outdoor environments in the presence or absence of interfering substances. Our results indicate that transmission of SARS-CoV-2 is unlikely to occur through outdoor surfaces, dependent on illuminance intensity. Moreover, most studies are interested in lineage S of SARS-CoV-2. In our experiments, we studied the stability of L-type strains, which comprise the majority of strains isolated from worldwide patients. Nevertheless, the effect of sunlight seems to be similar regardless of the strain studied, suggesting that the greater spread of certain variants is not correlated with better survival in outdoor conditions.

Low risk of SARS-CoV-2 transmission via fomite, even in cold-chain

BACKGROUND

Countries continue to debate the need for decontamination of cold-chain food packaging to reduce possible SARS-CoV-2 fomite transmission among workers. While laboratory-based studies demonstrate persistence of SARS-CoV-2 on surfaces, the likelihood of fomite-mediated transmission under real-life conditions is uncertain.

METHODS

Using a quantitative risk assessment model, we simulated in a frozen food packaging facility 1) SARS-CoV-2 fomite-mediated infection risks following worker exposure to contaminated plastic packaging; and 2) reductions in these risks attributed to masking, handwashing, and vaccination.

FINDINGS

In a representative facility with no specific interventions, SARS-CoV-2 infection risk to a susceptible worker from contact with contaminated packaging was 2·8 × 10 -3 per 1h-period (95%CI: 6·9 × 10 -6 , 2·4 × 10 -2 ). Implementation of standard infection control measures, handwashing and masks (9·4 × 10 -6 risk per 1h-period, 95%CI: 2·3 × 10 -8 , 8·1 × 10 -5 ), substantially reduced risk (99·7%). Vaccination of the susceptible worker (two doses Pfizer/Moderna, vaccine effectiveness: 86-99%) combined with handwashing and masking reduced risk to less than 1·0 × 10 -6 . Simulating increased infectiousness/transmissibility of new variants (2-, 10-fold viral shedding) among a fully vaccinated workforce, handwashing and masks continued to mitigate risk (2·0 × 10 -6 -1·1 × 10 -5 risk per 1h-period). Decontamination of packaging in addition to these interventions reduced infection risks to below the 1·0 × 10 -6 risk threshold.

INTERPRETATION

Fomite-mediated SARS-CoV-2 infection risks were very low under cold-chain conditions. Handwashing and masking provide significant protection to workers, especially when paired with vaccination.

FUNDING

U.S. Department of Agriculture.

A realistic transfer method reveals low risk of SARS-CoV-2 transmission via contaminated euro coins and banknotes

The current severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has created a significant threat to global health. While respiratory aerosols or droplets are considered as the main route of human-to-human transmission, secretions expelled by infected individuals can also contaminate surfaces and objects, potentially creating the risk of fomite-based transmission. Consequently, frequently touched objects such as paper currency and coins have been suspected as potential transmission vehicle. To assess the risk of SARS-CoV-2 transmission by banknotes and coins, we examined the stability of SARS-CoV-2 and bovine coronavirus, as surrogate with lower biosafety restrictions, on these different means of payment and developed a touch transfer method to examine transfer efficiency from contaminated surfaces to fingertips. Although we observed prolonged virus stability, our results indicate that transmission of SARS-CoV-2 via contaminated coins and banknotes is unlikely and requires high viral loads and a timely order of specific events.

Development of a Rapid Viability RT-PCR (RV-RT-PCR) Method to Detect Infectious SARS-CoV-2 from Swabs

Since the rapid onset of the COVID-19 pandemic, its causative virus, Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2), continues to spread and increase the number of fatalities. To expedite studies on understanding potential surface transmission of the virus and to aid environmental epidemiological investigations, we developed a rapid viability reverse transcriptase PCR (RV-RT-PCR) method that detects viable (infectious) SARS-CoV-2 from swab samples in <1 day compared to several days required by current gold-standard cell-culture-based methods. The method integrates cell-culture-based viral enrichment in a 96-well plate format with gene-specific RT-PCR-based analysis before and after sample incubation to determine the cycle threshold (C_T) difference (ΔC_T). An algorithm based on ΔC_T ≥ 6 representing ∼ 2-log or more increase in SARS-CoV-2 RNA following enrichment determines the presence of infectious virus. The RV-RT-PCR method with 2-hr viral infection and 9-hr post-infection incubation periods includes ultrafiltration to concentrate virions, resulting in detection of <50 SARS-CoV-2 virions in swab samples in 17 hours (for a batch of 12 swabs), compared to days typically required by the cell-culture based method. The SARS-CoV-2 RV-RT-PCR method may also be useful in clinical sample analysis and antiviral drug testing, and could serve as a model for developing rapid methods for other viruses of concern.

The viability of SARS-CoV-2 on solid surfaces

The COVID-19 pandemic had a major impact on life in 2020 and 2021. One method of transmission occurs when the causative virus, SARS-CoV-2, contaminates solids. Understanding and controlling the interaction with solids is thus potentially important for limiting the spread of the disease. We review work that describes the prevalence of the virus on common objects, the longevity of the virus on solids, and surface coatings that are designed to inactivate the virus. Engineered coatings have already succeeded in producing a large reduction in viral infectivity from surfaces. We also review work describing inactivation on facemasks and clothing and discuss probable mechanisms of inactivation of the virus at surfaces.

SARS Wars: the Fomites Strike Back

Controversy continues about the significance of fomite transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Recent papers continue to advocate concern. However, designs of studies showing virus survival on surfaces under laboratory conditions are unsuitable for extrapolation to real life. Although viral RNA is frequently found on real-life surfaces, actual tests for infectious virus are almost entirely negative, even in hospitals with COVID-19 patients. Fomite transmission should be regarded as no more than a very minor component of this pandemic.

Respiratory viruses in foods and their potential transmission through the diet: A review of the literature

Respiratory viruses are the main agents causing respiratory tract diseases. Nowadays, coronaviruses - and specifically, SARS-CoV-1, MERS-CoV and SARS-CoV-2 - are the principal responsible for the major epidemic outbreaks of the 21st century. The major routes of transmission for respiratory viruses - including coronaviruses - are via direct and indirect contacts. However, transmission through contaminated foods has not been extensively assessed. The present paper was aimed at reviewing scientific data on the transmission of respiratory viruses through potentially contaminated foods. While the current data seem to suggest that this route of transmission is not likely to occur, in order to increase the knowledge on this issue further investigations are still clearly necessary for a more complete prevention of the risks. Studies should include fresh produce and cooked foods. Anyway, prevention measures and good hygienic practices for both consumers and workers are mandatory when handling and cooking foods.

Survival of SARS-CoV-2 on Non-Porous Materials in an Experimental Setting Representative of Fomites

To better understand plausible SARS-CoV-2 transmission through fomites, a physiological model was designed to analyze the decay rate of SARS-CoV-2 infectivity. We focused on non-porous materials present in high-touch surfaces or used as containment barrier surfaces, namely glass, acrylic glass, photo-activated coated glass, stainless steel and aluminium. SARS-CoV-2 survival depended on the material considered, with half-lives on glass, photo-activated coated glass, stainless steel and aluminium equal to 6.9, 4.1, 3.5 and 2.3 h, respectively. This study highlights the potential utility of coatings in the fight against the current threat. In addition, it spotlights the need for standardizing assays to assess indirect transmission of COVID-19.

The Safety of Slaughterhouse Workers during the Pandemic Crisis

The working conditions in a slaughterhouse are difficult because of the low temperatures, high humidity, and little natural light. Therefore, in these facilities, there is a high demand in the maintenance of strict hygiene rules. Lately, the new SARS-CoV-2 pandemic situation has brought new challenges in the meat industry, as this sector has to maintain its operability to supply the meat and meat products demanded by the consumers. In this challenging period, the safety of the workers is as important as keeping the high demands for the safety of the meat and meat products along with consumer confidence. This paper aims to give an overview of the risks associated with the SARS-CoV-2 virus transmission between the workers in slaughterhouses and to evaluate the stability and infectivity in the working environment of these facilities. Considering the persistence of this virus on different surfaces and the environmental conditions affecting its stability (temperature, relative humidity, and natural light), in the study we proposed several short-, medium-, and long-term preventive measures for minimizing the potential threats of the actual pandemic.

SARS-CoV-2 Survival on Surfaces and the Effect of UV-C Light

The aim of this study was to establish the persistence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on inanimate surfaces such as plastic, stainless steel, and glass during UV-C irradiation which is a physical means commonly utilized in sanitization procedures. The viral inactivation rate, virus half-life, and percentage of titer reduction after UV-C irradiation were assessed. Infectivity was maintained on plastic and glass until 120 h and on stainless steel until 72 h. The virus half-life was 5.3, 4.4, and 4.2 h on plastic, stainless steel, and glass, respectively. In all cases, titer decay was >99% after drop drying. UV-C irradiation efficiently reduced virus titer (99.99%), with doses ranging from 10.25 to 23.71 mJ/cm². Plastic and stainless steel needed higher doses to achieve target reduction. The total inactivation of SARS-CoV-2 on glass was obtained with the lower dose applied. SARS-CoV-2 survival can be long lasting on inanimate surfaces. It is worth recommending efficient disinfection protocols as a measure of prevention of viral spread. UV-C can provide rapid, efficient and sustainable sanitization procedures of different materials and surfaces. The dosages and mode of irradiation are important parameters to consider in their implementation as an important means to fight the SARS-CoV-2 pandemic.

Understanding COVID-19 in Wuhan From the Perspective of Cold-Dampness: Clinical Evidences and Mechanisms

Traditional Chinese medicine (TCM) has played a significant role in the treatment of coronavirus disease 2019 (COVID-19) in Wuhan City. During the epidemic, Academician Tong Xiaolin suggested a close association of COVID-19 with cold-dampness, an etiological factor in TCM, by summarizing the characteristics of the COVID-19 patients in Wuhan. and the theory of Cold-dampness Plague was proposed. Based on the Cold-dampness Plague theory, a series of TCM drugs, such as Huoxiang Zhengqi Dropping Pills, Lianhua Qingwen Granules Hanshiyi Formula, and Tongzhi Granule were developed for the different stages, namely mild, moderate, severe, recovery, of the COVID-19. In addition, clinical evidences were obtained through randomized clinical trials or retrospective cohort studies. The Anti-SARS-CoV-2 mechanism of the TCM prescriptions were then summarized from the four aspects: targeting the ACE2 and 3CLPro, targeting cytokines, targeting acute immune responses to SARS-CoV-2, and targeting pulmonary fibrosis. Despite the clinical efficacy and therapeutic pharmacology speculation, more studies such as large-scale randomized clinical trials, cell and animal experiments are needed to further verify the theory of the Cold-dampness Plague in COVID-19 patients.