Transfer efficiency of bacteria and viruses from porous and nonporous fomites to fingers under different relative humidity conditions

Expert elicitation on the relative importance of possible SARS-CoV-2 transmission routes and the effectiveness of mitigations

OBJECTIVES

To help people make decisions about the most effective mitigation measures against SARS-CoV-2 transmission in different scenarios, the likelihoods of transmission by different routes need to be quantified to some degree (however uncertain). These likelihoods need to be communicated in an appropriate way to illustrate the relative importance of different routes in different scenarios, the likely effectiveness of different mitigation measures along those routes, and the level of uncertainty in those estimates. In this study, a pragmatic expert elicitation was undertaken to supply the underlying quantitative values to produce such a communication tool.

PARTICIPANTS

Twenty-seven individual experts from five countries and many scientific disciplines provided estimates.

OUTCOME MEASURES

Estimates of transmission parameters, assessments of the quality of the evidence, references to relevant literature, rationales for their estimates and sources of uncertainty.

RESULTS AND CONCLUSION

The participants' responses showed that there is still considerable disagreement among experts about the relative importance of different transmission pathways and the effectiveness of different mitigation measures due to a lack of empirical evidence. Despite these disagreements, when pooled, the majority views on each parameter formed an internally consistent set of estimates (for example, that transmission was more likely indoors than outdoors, and at closer range), which formed the basis of a visualisation to help individuals and organisations understand the factors that influence transmission and the potential benefits of different mitigation measures.

What We Are Learning from COVID-19 for Respiratory Protection: Contemporary and Emerging Issues

Infectious respiratory diseases such as the current COVID-19 have caused public health crises and interfered with social activity. Given the complexity of these novel infectious diseases, their dynamic nature, along with rapid changes in social and occupational environments, technology, and means of interpersonal interaction, respiratory protective devices (RPDs) play a crucial role in controlling infection, particularly for viruses like SARS-CoV-2 that have a high transmission rate, strong viability, multiple infection routes and mechanisms, and emerging new variants that could reduce the efficacy of existing vaccines. Evidence of asymptomatic and pre-symptomatic transmissions further highlights the importance of a universal adoption of RPDs. RPDs have substantially improved over the past 100 years due to advances in technology, materials, and medical knowledge. However, several issues still need to be addressed such as engineering performance, comfort, testing standards, compliance monitoring, and regulations, especially considering the recent emergence of pathogens with novel transmission characteristics. In this review, we summarize existing knowledge and understanding on respiratory infectious diseases and their protection, discuss the emerging issues that influence the resulting protective and comfort performance of the RPDs, and provide insights in the identified knowledge gaps and future directions with diverse perspectives.

Food Safety and Employee Health Implications of COVID-19: A Review

The COVID-19 pandemic has greatly impacted the U.S. food supply and consumer behavior. Food production and processing are being disrupted as illnesses, proactive quarantines, and government-mandated movement restrictions cause labor shortages. In this environment, the food industry has been required to adopt new, additional practices to minimize the risk of COVID-19 cases and outbreaks among its workforce. Successfully overcoming these challenges requires a comprehensive approach that addresses COVID-19 transmission both within and outside the facility. Possible interventions include strategies (i) to vaccinate employees, (ii) to assure that employees practice social distancing, (iii) to assure that employees wear face coverings, (iv) to screen employees for COVID-19, (v) to assure that employees practice frequent hand washing and avoid touching their faces, (vi) to clean frequently touched surfaces, and (vii) to assure proper ventilation. Compliance with these control strategies must be verified, and an overall COVID-19 control culture must be established to implement an effective program. Despite some public misperceptions about the health risk of severe acute respiratory syndrome coronavirus 2 on foods or food packaging, both the virus biology and epidemiological data clearly support a negligible risk of COVID-19 transmission through food and food packing. However, COVID-19 pandemic-related supply chain and workforce disruptions and the shift in resources to protect food industry employees from COVID-19 may increase the actual food safety risks. The goal of this review was to describe the COVID-19 mitigation practices adopted by the food industry and the potential impact of these practices and COVID-19-related disruptions on the industry's food safety mission. A review of these impacts is necessary to ensure that the food industry is prepared to maintain a safe and nutritious food supply in the face of future global disruptions.

Transfer Rate of Enveloped and Nonenveloped Viruses between Fingerpads and Surfaces

Fomites can represent a reservoir for pathogens, which may be subsequently transferred from surfaces to skin. In this study, we aim to understand how different factors (including virus type, surface type, time since last hand wash, and direction of transfer) affect virus transfer rates, defined as the fraction of virus transferred, between fingerpads and fomites. To determine this, 360 transfer events were performed with 20 volunteers using Phi6 (a surrogate for enveloped viruses), MS2 (a surrogate for nonenveloped viruses), and three clean surfaces (stainless steel, painted wood, and plastic). Considering all transfer events (all surfaces and both transfer directions combined), the mean transfer rates of Phi6 and MS2 were 0.17 and 0.26, respectively. Transfer of MS2 was significantly higher than that of Phi6 (P < 0.05). Surface type was a significant factor that affected the transfer rate of Phi6: Phi6 is more easily transferred to and from stainless steel and plastic than to and from painted wood. Direction of transfer was a significant factor affecting MS2 transfer rates: MS2 is more easily transferred from surfaces to fingerpads than from fingerpads to surfaces. Data from these virus transfer events, and subsequent transfer rate distributions, provide information that can be used to refine quantitative microbial risk assessments. This study provides a large-scale data set of transfer events with a surrogate for enveloped viruses, which extends the reach of the study to the role of fomites in the transmission of human enveloped viruses like influenza and SARS-CoV-2. IMPORTANCE This study created a large-scale data set for the transfer of enveloped viruses between skin and surfaces. The data set produced by this study provides information on modeling the distribution of enveloped and nonenveloped virus transfer rates, which can aid in the implementation of risk assessment models in the future. Additionally, enveloped and nonenveloped viruses were applied to experimental surfaces in an equivalent matrix to avoid matrix effects, so results between different viral species can be directly compared without confounding effects of different matrices. Our results indicating how virus type, surface type, time since last hand wash, and direction of transfer affect virus transfer rates can be used in decision-making processes to lower the risk of viral infection from transmission through fomites.

Effects of patient room layout on viral accruement on healthcare professionals' hands

Healthcare professionals (HCPs) are exposed to highly infectious viruses, such as norovirus, through multiple exposure routes. Understanding exposure mechanisms will inform exposure mitigation interventions. The study objective was to evaluate the influences of hospital patient room layout on differences in HCPs' predicted hand contamination from deposited norovirus particles. Computational fluid dynamic (CFD) simulations of a hospital patient room were investigated to find differences in spatial deposition patterns of bioaerosols for right-facing and left-facing bed layouts under different ventilation conditions. A microbial transfer model underpinned by observed mock care for three care types (intravenous therapy (IV) care, observational care, and doctors' rounds) was applied to estimate HCP hand contamination. Viral accruement was contrasted between room orientation, care type, and by assumptions about whether bioaerosol deposition was the same or variable by room orientation. Differences in sequences of surface contacts were observed for care type and room orientation. Simulated viral accruement differences between room types were influenced by mostly by differences in bioaerosol deposition and by behavior sequences when deposition patterns for the room orientations were similar. Differences between care types were likely driven by differences in hand-to-patient contact frequency, with doctors' rounds resulting in the greatest predicted viral accruement on hands.

Liquid repellency enabled antipathogen coatings

Currently, Coronavirus Disease 2019 (COVID-19)-a respiratory contagion spreading through expiratory droplets-has evolved into a global pandemic, severely impacting the public health. Importantly, the emerging of immune evasion SARS-CoV-2 variants and the limited effect of current antivirals against SARS-CoV-2 in clinical trials suggested that alternative strategies in addition to the conventional vaccines and antivirals are required to successfully control the COVID-19 pandemic. Here, we propose to use liquid-repellent coatings to prevent the spread of the disease in the absence of effective vaccines, antimicrobial agents, or therapeutics, wherein the deposition and penetration of pathogen droplets are prohibited. We use SARS-CoV-2 as a model pathogen and find that SARS-CoV-2 remnants are reduced by seven orders of magnitude on coated surfaces, yielding a repelling efficacy far outperforming the inactivation rate of disinfectants. The SARS-CoV-2 remnant scales exponentially with the liquid/solid adhesion, uncovering the mechanism and effective means for minimizing pathogen attachment. The antipathogen coating that both repels and inactivates pathogens is demonstrated by incorporating the super-liquid-repellent coating with antipathogen additives. Together with its versatility over a wide range of substrates and pathogens, the novel antipathogen coating is of considerable value for infection control in everyday life as well as during pandemics.

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.

Surface touch network structure determines bacterial contamination spread on surfaces and occupant exposure

Fomites are known to spread infectious diseases, but their role in determining transmission risk remains unclear. The association of surface touch networks (STNs), proposed to explain this risk, with real-life surface contamination has not yet been demonstrated. To construct STNs, we collected surface touch data from 23 to 26 scholars through 2 independent experiments conducted in office spaces for 13 h each. In parallel, a tracer bacterium (Lactobacillus bulgaricus) was spread by a designated carrier in each experiment during normal activities; the subsequent extent of surface contamination was assessed using qPCR. The touch data were also analyzed using an agent-based model that predicted the observed contamination. Touching public (door handles) and hidden public (desks, chair seatbacks) surfaces that connected occupants, sparse hand-to-hand contact, and active carriers contributed significantly to contamination spread, which was also correlated with the size of the social group containing carriers. The natural and unsupervised experiments reflected realistic exposure levels of mouths (1-10 ppm of total contamination spread by one root carrier), nostrils (~1 ppm), and eyes (~0.1 ppm). We conclude that the contamination degree of known and hidden public surfaces can indicate fomite exposure risk. The social group effect could trigger superspreading events through fomite transmission.

A Tn-seq Screen of Streptococcus pneumoniae Uncovers DNA Repair as the Major Pathway for Desiccation Tolerance and Transmission

Streptococcus pneumoniae is an opportunistic pathogen that is a common cause of serious invasive diseases such as pneumonia, bacteremia, meningitis, and otitis media. Transmission of this bacterium has classically been thought to occur through inhalation of respiratory droplets and direct contact with nasal secretions. However, the demonstration that S. pneumoniae is desiccation tolerant and, therefore, environmentally stable for extended periods of time opens up the possibility that this pathogen is also transmitted via contaminated surfaces (fomites). To better understand the molecular mechanisms that enable S. pneumoniae to survive periods of desiccation, we performed a high-throughput transposon sequencing (Tn-seq) screen in search of genetic determinants of desiccation tolerance. We identified 42 genes whose disruption reduced desiccation tolerance and 45 genes that enhanced desiccation tolerance. The nucleotide excision repair pathway was the most enriched category in our Tn-seq results, and we found that additional DNA repair pathways are required for desiccation tolerance, demonstrating the importance of maintaining genome integrity after desiccation. Deletion of the nucleotide excision repair gene uvrA resulted in a delay in transmission between infant mice, indicating a correlation between desiccation tolerance and pneumococcal transmssion. Understanding the molecular mechanisms that enable pneumococcal persistence in the environment may enable targeting of these pathways to prevent fomite transmission, thereby preventing the establishment of new colonization and any resulting invasive disease.

Human Coronaviruses Do Not Transfer Efficiently between Surfaces in the Absence of Organic Materials

Human coronaviruses, including SARS-CoV-2, are known to spread mainly via close contact and respiratory droplets. However, other potential means of transmission may be present. Fomite-mediated transmission occurs when viruses are deposited onto a surface and then transfer to a subsequent individual. Surfaces can become contaminated directly from respiratory droplets or from a contaminated hand. Due to mask mandates in many countries around the world, the former is less likely. Hands can become contaminated if respiratory droplets are deposited on them (i.e., coughing or sneezing) or through contact with fecal material where human coronaviruses (HCoVs) can be shed. The focus of this paper is on whether human coronaviruses can transfer efficiently from contaminated hands to food or food contact surfaces. The surfaces chosen were: stainless steel, plastic, cucumber and apple. Transfer was first tested with cellular maintenance media and three viruses: two human coronaviruses, 229E and OC43, and murine norovirus-1, as a surrogate for human norovirus. There was no transfer for either of the human coronaviruses to any of the surfaces. Murine norovirus-1 did transfer to stainless steel, cucumber and apple, with transfer efficiencies of 9.19%, 5.95% and 0.329%, respectively. Human coronavirus OC43 transfer was then tested in the presence of fecal material, and transfer was observed for stainless steel (0.52%), cucumber (19.82%) and apple (15.51%) but not plastic. This study indicates that human coronaviruses do not transfer effectively from contaminated hands to contact surfaces without the presence of fecal material.

Recovery of Infectious Human Norovirus GII.4 Sydney From Fomites via Replication in Human Intestinal Enteroids

Contamination of fomites by human norovirus (HuNoV) can initiate and prolong outbreaks. Fomite swabbing is necessary to predict HuNoV exposure and target interventions. Historically, swab recovered HuNoV has been measured by molecular methods that detect viral RNA but not infectious HuNoV. The recent development of HuNoV cultivation in human intestinal enteroids (HIEs) enables detection of infectious HuNoV. It is unknown if the swabbing process and swab matrix will allow for cultivation of fomite recovered HuNoV. We used HIEs to culture swab-recovered HuNoV GII.4 Sydney from experimentally infected surfaces—a hospital bed tray (N = 32), door handle (N = 10), and sanitizer dispenser (N = 11). Each surface was swabbed with macrofoam swabs premoistened in PBS plus 0.02% Tween80. Swab eluate was tested for infectious HuNoV by cultivation in HIE monolayers. Infectious HuNoV can be recovered from surfaces inoculated with at least 10⁵ HuNoV genome equivalents/3 cm². In total, 57% (N = 53) of recovered swabs contained infectious HuNoV detected by HIEs. No difference in percent positive swabs was observed between the three surfaces at p = 0.2. We demonstrate that fomite swabbing can be combined with the HIE method to cultivate high titer infectious HuNoV from the environment, filling a significant gap in HuNoV detection. Currently, high titers of HuNoV are required to measure growth in HIEs and the HIE system precludes absolute quantification of infectious viruses. However, the HIE system can provide a binary indication of infectious HuNoV which enhances existing detection methods. Identification of infectious HuNoVs from swabs can increase monitoring accuracy, enhance risk estimates, and help prevent outbreaks.

Modelling disease transmission from touchscreen user interfaces

The extensive use of touchscreens for all manner of human-computer interactions has made them plausible instruments of touch-mediated disease transmission. To that end, we employ stochastic simulations to model human-fomite interaction with a distinct focus on touchscreen interfaces. The timings and frequency of interactions from within a closed population of infectious and susceptible individuals was modelled using a queuing network. A pseudo-reproductive number R was used to compare outcomes under various parameter conditions. We then apply the simulation to a specific real-world scenario; namely that of airport self-check-in and baggage drop. A counterintuitive result was that R decreased with increased touch rates required for touchscreen interaction. Additionally, as one of few parameters to be controlled, the rate of cleaning/disinfecting screens plays an essential role in mitigating R, though alternative technological strategies could prove more effective. The simulation model developed provides a foundation for future advances in more sophisticated fomite disease-transmission modelling.

Respirators, face masks, and their risk reductions via multiple transmission routes for first responders within an ambulance

First responders may have high SARS-CoV-2 infection risks due to working with potentially infected patients in enclosed spaces. The study objective was to estimate infection risks per transport for first responders and quantify how first responder use of N95 respirators and patient use of cloth masks can reduce these risks. A model was developed for two Scenarios: an ambulance transport with a patient actively emitting a virus in small aerosols that could lead to airborne transmission (Scenario 1) and a subsequent transport with the same respirator or mask use conditions, an uninfected patient; and remaining airborne SARS-CoV-2 and contaminated surfaces due to aerosol deposition from the previous transport (Scenario 2). A compartmental Monte Carlo simulation model was used to estimate the dispersion and deposition of SARS-CoV-2 and subsequent infection risks for first responders, accounting for variability and uncertainty in input parameters (i.e., transport duration, transfer efficiencies, SARS-CoV-2 emission rates from infected patients, etc.). Infection risk distributions and changes in concentration on hands and surfaces over time were estimated across sub-Scenarios of first responder respirator use and patient cloth mask use. For Scenario 1, predicted mean infection risks were reduced by 69%, 48%, and 85% from a baseline risk (no respirators or face masks used) of 2.9 × 10-2 ± 3.4 × 10-2 when simulated first responders wore respirators, the patient wore a cloth mask, and when first responders and the patient wore respirators or a cloth mask, respectively. For Scenario 2, infection risk reductions for these same Scenarios were 69%, 50%, and 85%, respectively (baseline risk of 7.2 × 10-3 ± 1.0 × 10-2). While aerosol transmission routes contributed more to viral dose in Scenario 1, our simulations demonstrate the ability of face masks worn by patients to additionally reduce surface transmission by reducing viral deposition on surfaces. Based on these simulations, we recommend the patient wear a face mask and first responders wear respirators, when possible, and disinfection should prioritize high use equipment.

Laundry Hygiene and Odor Control: State of the Science

Laundering of textiles—clothing, linens, and cleaning cloths—functionally removes dirt and bodily fluids, which prevents the transmission of and reexposure to pathogens as well as providing odor control. Thus, proper laundering is key to controlling microbes that cause illness and produce odors. The practice of laundering varies from region to region and is influenced by culture and resources. This review aims to define laundering as a series of steps that influence the exposure of the person processing the laundry to pathogens, with respect to the removal and control of pathogens and odor-causing bacteria, while taking into consideration the types of textiles. Defining laundering in this manner will help better educate the consumer and highlight areas where more research is needed and how to maximize products and resources. The control of microorganisms during laundering involves mechanical (agitation and soaking), chemical (detergent and bleach), and physical (detergent and temperature) processes. Temperature plays the most important role in terms of pathogen control, requiring temperatures exceeding 40°C to 60°C for proper inactivation, while detergents play a role in reducing the microbial load of laundering through the release of microbes attached to fabrics and the inactivation of microbes sensitive to detergents (e.g., enveloped viruses). The use of additives (enzymes) and bleach (chlorine and activated oxygen) becomes essential in washes with temperatures below 20°C, especially for certain enteric viruses and bacteria. A structured approach is needed that identifies all the steps in the laundering process and attempts to identify each step relative to its importance to infection risk and odor production.

The habit of finger-licking: getting a solution out of the pandemic

The habit of finger-licking is an insanitary habit observed everywhere including hospital wards and other medical facilities, among providers and other staff members. It is an enduring habit that has been present before and during the pandemic and will continue unless serious notice of it is taken. Herein, we illustrate the risks imposed by this everyday habit on individuals practicing it and on surrounding people, we describe the challenges with prior attempts to defeat this habit, and we explain how the face mask can eliminate this ever-lasting habit.

Evaluation of a Domestic Steam Disinfector-Dryer Device for Disinfection of Health Care Workers' Identification Lanyards

BACKGROUND

Fabric lanyards are commonly worn by health care workers (HCWs) and are known to harbor infectious organisms and contribute to the transmission of infection to HCWs and patients. A diverse range of nosocomial pathogens have been found on lanyards, but there are very few studies describing how to successfully disinfect lanyards to break the chain of transmission. Recently, a steam disinfector-dryer device has come on the market, which performs rapid disinfection against nosocomial pathogens and also dries the contents of the device. It was the aim of this study to evaluate steam disinfection-drying as a method to eliminate pathogens from lanyards.

METHODS

Thirty-eight strips of new, unused, and autoclaved polyester neck lanyards (4 × 2 cm) were inoculated with 30 (12 Gram-positive + 18 Gram-negative) bacteria and one yeast organism. The inoculated lanyard fabric (five organisms per lanyard strip) was placed into a steam disinfector-dryer device and disinfected for 5 minutes and dried for 30 minutes, in accordance with the manufacturer's instructions. Following disinfection and drying, the presence of viable organisms on lanyard fabric was evaluated using enhanced microbiological broth culture methods for 48 hours. Control lanyard strips were treated with organisms and left at room temperature without undergoing disinfection and drying procedures.

FINDINGS

Steam disinfection-drying eradicated all test organisms from treated lanyards, with no culturable organisms detected following disinfection-drying, even when employing enhanced bacteriological culture conditions. All test organisms remained viable on the control lanyards.

CONCLUSION/APPLICATION TO PRACTICE

Steam disinfection-drying offers a simple method of decontaminating lanyards, producing dry lanyards for immediate reuse. Occupational health practitioners and hospitals should consider assessing the feasibility of adopting this method in their settings to aid in breaking the chain of transmission of nosocomial pathogens via contaminated lanyards.

Copper as an antimicrobial agent: recent advances

From its uses in ancient civilisations, copper has an established history as an antimicrobial agent. Extensive research has determined the efficacy and mechanism of copper's antimicrobial activity against microorganisms. The process is multifaceted with the main mechanism of bactericidal activity being the generation of reactive oxygen species (ROS), which irreversibly damages membranes. Copper ions released from surfaces lead to RNA degradation and membrane disruption of enveloped viruses. For fungi, the mechanism involves the physical deterioration of the membrane and copper ion influx. Due to variations in the experimental parameters, it is difficult to compare studies directly. In this review article, we outline the importance of the experimental conditions currently employed and how they bear little resemblance to real-world conditions. We endorse previous recommendations calling for an update to industrial standard tests.

Modeling and Experimental Validation of Microbial Transfer via Surface Touch

Surface touch spreads disease-causing microbes, but the measured rates of microbial transfer vary significantly. Additionally, the mechanisms underlying microbial transfer via surface touch are unknown. In this study, a new physical model was proposed to accurately evaluate the microbial transfer rate in a finger-surface touch, based on the mechanistic effects of important physical factors, including surface roughness, surface wetness, touch force, and microbial transfer direction. Four surface-touch modes were distinguished, namely, a single touch, sequential touches (by different recipients), repeated touches (by the same recipient), and a touch with rubbing. The tested transfer rates collated from 26 prior studies were compared with the model predictions based on their experimental parameters, and studies in which the transfer rates were more consistent with our model predictions were identified. New validation experiments were performed by accurately controlling the parameters involved in the model. Four types of microbes were used to transfer between the naked finger and metal surface with the assistance of a purpose-made touch machine. The measured microbial transfer rate data in our new experiments had a smaller standard deviation than those reported from prior studies and were closer to the model prediction. Our novel predictive model sheds light on possible future studies.

Fomite Transmission, Physicochemical Origin of Virus-Surface Interactions, and Disinfection Strategies for Enveloped Viruses with Applications to SARS-CoV-2

Inanimate objects or surfaces contaminated with infectious agents, referred to as fomites, play an important role in the spread of viruses, including SARS-CoV-2, the virus responsible for the COVID-19 pandemic. The long persistence of viruses (hours to days) on surfaces calls for an urgent need for effective surface disinfection strategies to intercept virus transmission and the spread of diseases. Elucidating the physicochemical processes and surface science underlying the adsorption and transfer of virus between surfaces, as well as their inactivation, is important for understanding how diseases are transmitted and for developing effective intervention strategies. This review summarizes the current knowledge and underlying physicochemical processes of virus transmission, in particular via fomites, and common disinfection approaches. Gaps in knowledge and the areas in need of further research are also identified. The review focuses on SARS-CoV-2, but discussion of related viruses is included to provide a more comprehensive review given that much remains unknown about SARS-CoV-2. Our aim is that this review will provide a broad survey of the issues involved in fomite transmission and intervention to a wide range of readers to better enable them to take on the open research challenges.

Community Transmission of SARS-CoV-2 by Surfaces: Risks and Risk Reduction Strategies

SARS-CoV-2, the virus responsible for the COVID-19 pandemic, is perceived to be primarily transmitted via person-to-person contact through droplets produced while talking, coughing, and sneezing. Transmission may also occur through other routes, including contaminated surfaces; nevertheless, the role that surfaces have on the spread of the disease remains contested. Here, we use the Quantitative Microbial Risk Assessment framework to examine the risks of community transmission of SARS-CoV-2 through surfaces and to evaluate the effectiveness of hand and surface disinfection as potential interventions. Using conservative assumptions on input parameters of the model (e.g., dose-response relationship, ratio of genome copies to infective virus), the average of the median risks for single hand-to-surface contact followed by hand-to-face contact range from 1.6 × 10-4 to 5.6 × 10-9 for modeled prevalence rates of 0.2%-5%. For observed prevalence rates (0.2%, 1%), this corresponds to a low risk of infection (<10-6). Hand disinfection substantially reduces risks of transmission independently of the disease's prevalence and contact frequency. In contrast, the effectiveness of surface disinfection is highly dependent on the prevalence and the frequency of contacts. The work supports the current perception that contaminated surfaces are not a primary mode of transmission of SARS-CoV-2 and affirms the benefits of making hand disinfectants widely available.

3D printing of face shields to meet the immediate need for PPE in an anesthesiology department during the COVID-19 pandemic

Background

Anesthesia providers are at risk for contracting COVID-19 due to close patient contact, especially during shortages of personal protective equipment. We present an easy to follow and detailed protocol for producing 3D printed face shields and an effective decontamination protocol, allowing their reuse.

Methods

The University of Nebraska Medical Center (UNMC) produced face shields using a combination of 3D printing and assembly with commonly available products, and produced a simple decontamination protocol to allow their reuse. To evaluate the effectiveness of the decontamination protocol, we inoculated bacterial suspensions of E. coli and S. aureus on to the face shield components, performed the decontamination procedure, and finally swabbed and enumerated organisms onto plates that were incubated for 12-24 hours. Decontamination effectiveness was evaluated using the average log10 reduction in colony counts.

Results

Approximately 112 face shields were constructed and made available for use in 72 hours. These methods were successfully implemented for in-house production at UNMC and at Tripler Army Medical Center (Honolulu, Hawaii). Overall, the decontamination protocol was highly effective against both E. coli and S. aureus, achieving a ≥4 log10 (99.99%) reduction in colony counts for every replicate from each component of the face shield unit.

Discussion

Face shields not only act as a barrier against the soiling of N95 face masks, they also serve as more effective eye protection from respiratory droplets over standard eye shields. Implementation of decontamination protocols successfully allowed face shield and N95 mask reuse, offering a higher level of protection for anesthesiology providers at the onset of the COVID-19 pandemic.

Conclusions

In a time of urgent need, our protocol enabled the rapid production of face shields by individuals with little to no 3D printing experience, and provided a simple and effective decontamination protocol allowing reuse of the face shields.

Longitudinal Monitoring of SARS-CoV-2 RNA on High-Touch Surfaces in a Community Setting

Environmental surveillance of surface contamination is an unexplored tool for understanding transmission of SARS-CoV-2 in community settings. We conducted longitudinal swab sampling of high-touch non-porous surfaces in a Massachusetts town during a COVID-19 outbreak from April to June 2020. Twenty-nine of 348 (8.3%) surface samples were positive for SARS-CoV-2 RNA, including crosswalk buttons, trash can handles, and door handles of essential business entrances (grocery store, liquor store, bank, and gas station). The estimated risk of infection from touching a contaminated surface was low (less than 5 in 10,000) by quantitative microbial risk assessment, suggesting fomites play a minimal role in SARS-CoV-2 community transmission. The weekly percentage of positive samples (out of n = 33 unique surfaces per week) best predicted variation in city-level COVID-19 cases with a 7-day lead time. Environmental surveillance of SARS-CoV-2 RNA on high-touch surfaces may be a useful tool to provide early warning of COVID-19 case trends.

An agent-based modeling approach to estimate pathogen exposure risks from wheelchairs

BACKGROUND

Contributions of contaminated wheelchairs to nosocomial pathogen transmission are relatively unknown. Our aim was to develop a model predicting pathogen exposures for patients utilizing wheelchairs and estimate exposure reduction potential of wheelchair disinfection between rides.

METHODS

An agent-based model was informed by wheelchair location data from a connected 215-bed acute care and 250-bed long-term care facility. Simulated scenarios varied in frequencies of patient wheelchair contamination and wheelchair disinfection in between trips. Clostridioides difficile and methicillin-resistant Staphylococcus aureus concentrations on patient hands at the end of wheelchair trips were estimated. Exposure reductions due to disinfection, assuming low real-world efficacies (50%, 70%, and 90%), were compared.

RESULTS

In the simulation, when few patients introduced contamination to wheelchairs, disinfection in between patients 50% of the time decreased baseline (no disinfection) estimated exposures for the 50th wheelchair rider by >99.999%. When patients had a 50% chance of being contaminated before the wheelchair ride, disinfection did not reduce exposures consistently.

DISCUSSION

The efficacy of disinfection in between patient rides as an exposure mitigation strategy likely depends on the frequency of infected patient wheelchair use.

CONCLUSIONS

During outbreak, high contamination conditions, disinfection, alone, is not enough to protect patients from wheelchair-mediated exposures.

Comparison of electric hand dryers and paper towels for hand hygiene: a critical review of the literature

Numerous studies are published on the benefits of electric hand dryers vs paper towels (PT) for drying hands after washing. Data are conflicting and lacking key variables needed to assess infection risks. We provide a rapid scoping review on hand-drying methods relative to hygiene and health risks. Controlled vocabulary terms and keywords were used to search PubMed (1946-2018) and Embase (1947-2018). Multiple researchers independently screened abstracts for relevance using predetermined criteria and created a quality assessment scoring system for relative study comparisons. Of 293 papers, 23 were included in the final analysis. Five studies did not compare multiple methods; however, 2 generally favoured electric dryers (ED); 7 preferred PT; and 9 had mixed or statistically insignificant results (among these, 3 contained scenarios favourable to ED, 4 had results supporting PT, and the remaining studies had broadly conflicting results). Results were mixed among and within studies and many lacked consistent design or statistical analysis. The breadth of data does not favour one method as being more hygienic. However, some authors extended generalizable recommendations without sufficient scientific evidence. The use of tools in quantitative microbial risk assessment is suggested to evaluate health exposure potentials and risks relative to hand-drying methods. We found no data to support any human health claims associated with hand-drying methods. Inconclusive and conflicting results represent data gaps preventing the advancement of hand-drying policy or practice recommendations.

Current understanding of the surface contamination and contact transmission of SARS-CoV-2 in healthcare settings

The novel coronavirus disease (COVID-19) has rapidly spread across the world and was subsequently declared as a pandemic in 2020. To overcome this public health challenge, comprehensive understanding of the disease transmission is urgently needed. Recent evidences suggest that the most common route of transmission for SARS-CoV-2 is likely via droplet, aerosol, or direct contact in a person-to-person encounter, although the possibility of transmission via fomites from surfaces cannot be ruled out entirely. Environmental contamination in COVID-19 patient rooms is widely observed due to viral shedding from both asymptomatic and symptomatic patients, and SARS-CoV-2 can survive on hospital surfaces for extended periods. Sequence of contact events can spread the virus from one surface to the other in a hospital setting. Here, we review the studies related to viral shedding by COVID-19 patients that can contaminate surfaces and survival of SARS-CoV-2 on different types of surfaces commonly found in healthcare settings, as well as evaluating the importance of surface to person transmission characteristics. Based on recent evidences from the literature, decontamination of hospital surfaces should constitute an important part of the infection control and prevention of COVID-19.

Public Health Risk Assessment of the Door Handles of the Community Pharmacies in Qassim Region, Saudi Arabia

Door handles are being reported to harbor a diverse group of microorganisms, mainly bacteria. Presence of pathogenic and antibiotic-resistant bacteria in the door handles carry risk to the health of the public. For this reason, a study was carried in the Qassim region of Saudi Arabia by isolating bacteria from the pharmacy door handles from four different areas. Total 100 samples were collected by wiping the door handles with a sterile cotton swab soaked in sterile water. Microorganisms were isolated using Blood agar and MacConkey agar and identified following standard microbiological procedure. Siemens MicroScan Walkaway system was used for determination of antibiotic susceptibility pattern. In total, 301 bacteria from 13 bacterial species were isolated and identified. The predominant bacterial species include Staphylococcus spp. 56.48% followed by Bacillus spp. 12.29% and Micrococcus spp. 10.30%. Gram-negative bacteria like Shigella sonnei and Salmonella paratyphiA were also isolated. Being the most predominant species, Antibiotic resistance pattern of 39 Staphylococcus spp. were determined. 38.46% of the Staphylococcus spp. were found to be resistant to Cefoxitin, and 30.76% were beta-lactamase producing. The results also indicated that about one -third of Staphylococcus spp. were methicillin resistant. The door handles of pharmacies in the Qassim region carry risk to the health of the public. Proper hygienic measures are recommended for the public health safety until doors are made automatic and touch-free.

Surface texture limits transfer of S. aureus, T4 bacteriophage, influenza B virus and human coronavirus

Spread of pathogens on contaminated surfaces plays a key role in disease transmission. Surface technologies that control pathogen transfer can help control fomite transmission and are of great interest to public health. Here, we report a novel bead transfer method for evaluating fomite transmission in common laboratory settings. We show that this method meets several important criteria for quantitative test methods, including reasonableness, relevancy, resemblance, responsiveness, and repeatability, and therefore may be adaptable for standardization. In addition, this method can be applied to a wide variety of pathogens including bacteria, phage, and human viruses. Using the bead transfer method, we demonstrate that an engineered micropattern limits transfer of Staphylococcus aureus by 97.8% and T4 bacteriophage by 93.0% on silicone surfaces. Furthermore, the micropattern significantly reduces transfer of influenza B virus and human coronavirus on silicone and polypropylene surfaces. Our results highlight the potential of using surface texture as a valuable new strategy in combating infectious diseases.

Food safety lessons learned from the COVID-19 pandemic

The COVID‐19 pandemic has ushered in a new era of food safety. To date, there is no evidence to suggest that consuming food is associated with COVID‐19. Nevertheless, COVID‐19's impact on food safety and security has been grave. The world is currently experiencing several supply chain issues as a direct result of extensive lockdowns and impacts on essential workers' safety. However, disruption in the food supply, while catastrophic in nature, has created opportunities for the advancement of medical science, data processing, security monitoring, foodborne pathogen detection, and food safety technology. This article will discuss the key components for food safety during the COVID‐19 pandemic. The discussion will draw from lessons learned early in the outbreak and will analyze the etiology of the disease through a food safety perspective. From there, we will discuss personal protective equipment, detection of SARS‐CoV‐2, useful surrogates to study SARS‐CoV‐2, and the expanding field of data science, from the food safety point of view. In the future, scientists can apply the knowledge to the containment of COVID‐19 and eventually to future pandemics.

Longitudinal Study of Viral and Bacterial Contamination of Hospital Pediatricians' Mobile Phones

Mobile phones (MPs) of healthcare workers (HCWs) may represent an important source of transmission of infectious agents. This longitudinal study documents the contamination of these tools. Ten MPs handled by senior pediatricians were sampled once a week during 23 weeks in three pediatric wards of the University Hospital of Saint-Etienne, France. Cultures were performed for bacteria and multiplex PCR assays for a panel of respiratory and enteric viruses. A questionnaire on hygiene habits regarding phoning and care was filled-in by pediatricians before and after the study. From a total of 230 samples, 145 (63%) were contaminated by at least one pathogen. The MPs from emergency departments were the most impacted. Viruses were detected in 179 samples; bacteria were isolated in 59 samples. Contamination increased during the winter epidemic peak. A cross-contamination by Paracoccus yeei between hands and MPs of different HCWs was demonstrated. The communication of the study results influenced the hygiene behaviors. This study highlights the contamination of MPs by pathogens that are resistant in the environment, and its sustainability along the winter season. The role of MPs as vectors of nosocomial infection needs to be better investigated.

Methicillin Resistant Staphylococcus aureus and public fomites: a review

Staphylococcus genus is a Gram-positive coccus normally associated with skin and mucous membranes of warm-blooded animals. It is part of the commensal human microflora, or found in animals, or contaminating surfaces in the community and hospital settings. Staphylococcus aureus is the most pathogenic species belonging to this genus, as it possesses a collection of virulence factors that are expressed solely to evade the immune system. The increase in the misuse of antimicrobial agents predisposed S. aureus to develop antibiotic resistance, including the resistance to methicillin which led to the emergence of Methicillin-Resistant S. aureus (MRSA). MRSA is considered one of the most dangerous nosocomial pathogens causing many hard to treat infections in hospitals and was named as Hospital Associated MRSA (HA-MRSA). Over the past 20-25 years, MRSA was isolated from community settings and thus Community Associated MRSA (CA-MRSA) has emerged. Inside hospitals, MRSA has been isolated from fomites in contact with patients, as well as staff's protective and personal items. This review highlights the worldwide prevalence of MRSA on fomites within the contexts of hospital and community settings.

Multidrug-resistant Opportunistic and Pathogenic Bacteria Contaminate Algerian Banknotes Currency

Currency is one of the most exchanged items in human communities as it is used daily in exchange for goods and services. It is handled by persons with different hygiene standards and can transit in different environments. Hence, money can constitute a reservoir for different types of human pathogens. This study aimed to evaluate the potential of Algerian banknotes to shelter opportunistic pathogenic and multiresistant bacteria. To that end, 200 circulating notes of four different denominations were collected from various places and analyzed for their bacterial loads and contents. Besides, predominant strains were identified and characterized by biochemical and molecular methods, and their resistance profiles against 34 antibiotics were determined. Our results indicated that 100% of the studied banknotes were contaminated with bacteria. The total bacterial concentrations were relatively high, and different bacterial groups were grown, showing important diversity. In total, 48 predominant strains were identified as belonging to 17 genera. Staphylococcus and Micrococcus were the most prevalent genera, followed by Bacillus, Pseudomonas, and Acinetobacter. Antibiotic susceptibility testing showed that all the isolates harbored resistance to at least two molecules, and worrying resistance levels were observed. These findings prove that Algerian currency harbors opportunistic multiresistant bacteria and could potentially act as a vehicle for the spread of bacterial diseases and as a reservoir for antibiotic resistance genes among the community. Therefore, no cash payment systems should be developed and generalized to minimize cash handling and subsequent potential health risks.

Why is mock care not a good proxy for predicting hand contamination during patient care?

BACKGROUND

Healthcare worker (HCW) behaviours, such as the sequence of their contacts with surfaces and hand hygiene moments, are important for understanding disease transmission.

AIM

To propose a method for recording sequences of HCW behaviours during mock vs actual procedures, and to evaluate differences for use in infection risk modelling and staff training.

METHODS

Procedures for three types of care were observed under mock and actual settings: intravenous (IV) drip care, observational care and doctors' rounds on a respiratory ward in a university teaching hospital. Contacts and hand hygiene behaviours were recorded in real-time using either a handheld tablet or video cameras.

FINDINGS

Actual patient care demonstrated 70% more surface contacts than mock care. It was also 2.4 min longer than mock care, but equal in terms of patient contacts. On average, doctors' rounds took 7.5 min (2.5 min for mock care), whilst auxiliary nurses took 4.9 min for observational care (2.4 min for mock care). Registered nurses took 3.2 min for mock IV care and 3.8 min for actual IV care; this translated into a 44% increase in contacts. In 51% of actual care episodes and 37% of mock care episodes, hand hygiene was performed before patient contact; in comparison, 15% of staff delivering actual care performed hand hygiene after patient contact on leaving the room vs 22% for mock care. The number of overall touches in the patient room was a modest predictor of hand hygiene. Using a model to predict hand contamination from surface contacts for Staphylococcus aureus, Escherichia coli and norovirus, mock care underestimated micro-organisms on hands by approximately 30%.

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

The unwavering spread of COVID-19 has taken the world by storm. Preventive measures like social distancing and mask usage have been taken all around the globe but still, as of September 2020, the number of cases continues to rise in many countries. Evidently, these measures are insufficient. Although decreases in population density and surges in the public's usage of personal protective equipment can mitigate direct transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), indirect transmission of the virus is still probable. By summarizing the current state of knowledge on the stability of coronaviruses on dry materials, this review uncovers the high potential for SARS-CoV-2 transmission through contaminated surfaces (i.e., fomites) and prompts future research. Fully contextualized data on coronavirus persistence are presented. The methods and limitations to testing the stability of coronaviruses are explored, and the SARS-CoV-2 representativeness of different coronaviruses is analyzed. The factors which dictate the persistence of coronaviruses on surfaces (media, environmental conditions, and material-type) are investigated, and the review is concluded by encouraging material innovation to combat the current pandemic. To summarize, SARS-CoV-2 remains viable on the timescale of days on hard surfaces under ambient indoor conditions. Similarly, the virus is stable on human skin, signifying the necessity of hand hygiene amidst the current pandemic. There is an inverse relationship between SARS-CoV-2 surface persistence and temperature/humidity, and the virus is well suited to air-conditioned environments (room temperature, ~ 40% relative humidity). Sunlight may rapidly inactivate the virus, suggesting that indirect transmission predominantly occurs indoors. The development of antiviral materials and surface coatings would be an extremely effective method to mitigate the spread of COVID-19. To obtain applicable data on the persistence of coronaviruses and the efficiency of virucidal materials, future researchers should understand the common experimental limitations outlined in this review and plan their studies accordingly.

Longitudinal monitoring of SARS-CoV-2 RNA on high-touch surfaces in a community setting

Environmental surveillance of surface contamination is an unexplored tool for understanding transmission of SARS-CoV-2 in community settings. We conducted longitudinal swab sampling of high-touch non-porous surfaces in a Massachusetts town during a COVID-19 outbreak from April to June 2020. Twenty-nine of 348 (8.3 %) surface samples were positive for SARS-CoV-2, including crosswalk buttons, trash can handles, and door handles of essential business entrances (grocery store, liquor store, bank, and gas station). The estimated risk of infection from touching a contaminated surface was low (less than 5 in 10,000), suggesting fomites play a minimal role in SARS-CoV-2 community transmission. The weekly percentage of positive samples (out of n=33 unique surfaces per week) best predicted variation in city-level COVID-19 cases using a 7-day lead time. Environmental surveillance of SARS-CoV-2 RNA on high-touch surfaces could be a useful tool to provide early warning of COVID-19 case trends.

The effectiveness and efficacy of respiratory protective equipment (RPE) in dentistry and other health care settings: a systematic review

OBJECTIVE

The global pandemic of coronavirus disease-19, caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), is the latest hazard facing healthcare workers (HCW) including dental care workers (DCW). It is clear that the major mode of SARS-CoV-2 transmission is the airborne route, through inhalation of virus-infested aerosols and droplets. Several respiratory protection equipment (RPE), including masks, face shields/visors, and respirators, are available to obviate facial and conjunctival contamination by microbes. However, as their barrier value against microbial inhalation has not been evaluated, we systematically reviewed the data on the effectiveness and efficacy of facemasks and respirators, including protective eyewear, with particular emphasis on dental healthcare.

MATERIAL AND METHODS

PubMed, MEDLINE, the Cochrane Library, and Embase databases were searched between 01January 1990 and 15 May 2020.

RESULTS

Of 310 identified English language records, 21 were included as per eligibility criteria. In clinical terms, wearing layered, face-fitting masks/respirators and protective-eyewear can limit the spread of infection among HCWs. Specifically, combined interventions such as a face mask and a face shield, better resist bioaerosol inhalation than either alone. The prolonged and over-extended use of surgical masks compromise their effectiveness.

CONCLUSIONS

In general, RPE is effective as a barrier protection against aerosolized microbes in healthcare settings. But their filtration efficacy is compromised by the (i) inhalant particle size, (ii) airflow dynamics, (iii) mask-fit factor, (iv) period of wear, (v) 'wetness' of the masks, and (vi) their fabrication quality. The macro-data presented here should inform policy formulation on RPE wear amongst HCWs.

Understanding building-occupant-microbiome interactions toward healthy built environments: A review

Built environments, occupants, and microbiomes constitute a system of ecosystems with extensive interactions that impact one another. Understanding the interactions between these systems is essential to develop strategies for effective management of the built environment and its inhabitants to enhance public health and well-being. Numerous studies have been conducted to characterize the microbiomes of the built environment. This review summarizes current progress in understanding the interactions between attributes of built environments and occupant behaviors that shape the structure and dynamics of indoor microbial communities. In addition, this review also discusses the challenges and future research needs in the field of microbiomes of the built environment that necessitate research beyond the basic characterization of microbiomes in order to gain an understanding of the causal mechanisms between the built environment, occupants, and microbiomes, which will provide a knowledge base for the development of transformative intervention strategies toward healthy built environments. The pressing need to control the transmission of SARS-CoV-2 in indoor environments highlights the urgency and significance of understanding the complex interactions between the built environment, occupants, and microbiomes, which is the focus of this review.

Mumps virus outbreak related to a water pipe (narghile) shared smoking

INTRODUCTION

This study describes a mumps outbreak among a group of young people who shared a same narghile to smoking. Saliva and blood samples were obtained from 3cases for RT-PCR and serology respectively.

METHODS

The notification of a mumps case started an epidemiological investigation. Information of other 6additional symptomatic persons who had gathered with the case in a discotheque where they smoking in a same narghile was achieved. RT-PCR positive samples were genotyped by sequencing.

RESULTS

The 7patients resided in 3different municipalities, and they do not have get together for more than a month until the meeting in the discotheque. Four cases were confirmed by RT-PCR and/or IgM determinations. The genomic investigation showed identical nucleic sequences.

CONCLUSIONS

This outbreak is consequence of the common use of a narghile to smoking. The public usage of these water pipes should be regulated.

A Review of Decontamination Methods for Filtering Facepiece Respirators

During the current COVID-19 infectious disease pandemic, the demand for NIOSH-approved filtering facepiece respirators (FFR) has exceeded supplies and decontamination and reuse of FFRs has been implemented by various user groups. FFR decontamination and reuse is only intended to be implemented as a crisis capacity strategy. This paper provides a review of decontamination procedures in the published literature and calls attention to their benefits and limitations. In most cases, the data are limited to a few FFR models and a limited number of decontamination cycles. Institutions planning to implement a decontamination method must understand its limitations in terms of the degree of inactivation of the intended microorganisms and the treatment's effects on the fit and filtration of the device.

Unusual routes for transmission of coronavirus disease (COVID-19): Recommendations to interrupt the vicious cycle of infection

The outbreak of the novel COVID-19, which began silently in Wuhan City, China, has now taken the form of a pandemic, with its claws spreading rapidly in many countries, with new and new cases emerging rapidly. The COVID-19-associated CoV is a beta coronavirus, which spreads at such a deadly rate that the World Health Organization (WHO) has to declare it a Public Health Emergency of International Concern (PHEIC). The objective of the narrative review is to describe what is COVID-19-related coronavirus (CoV), its structure and particle size, potential transmission routes, the risk of infection in patients undergoing blood transfusion or in patients with diabetes and cancer, and recommendations to prevent its spread in office settings, travel / recreation settings, residential and health facilities. This paper also discusses several groundbreaking approaches that are used to counter COVID-19. With this narrative review, we hope to raise awareness of the usual and unusual pathways of transmission and prevent the spread of this pandemic disease.

Nanotechnology Responses to COVID-19

Researchers, engineers, and medical doctors are made aware of the severity of the COVID-19 infection and act quickly against the coronavirus SARS-CoV-2 using a large variety of tools. In this review, a panoply of nanoscience and nanotechnology approaches show how these disciplines can help the medical, technical, and scientific communities to fight the pandemic, highlighting the development of nanomaterials for detection, sanitation, therapies, and vaccines. SARS-CoV-2, which can be regarded as a functional core-shell nanoparticle (NP), can interact with diverse materials in its vicinity and remains attached for variable times while preserving its bioactivity. These studies are critical for the appropriate use of controlled disinfection systems. Other nanotechnological approaches are also decisive for the development of improved novel testing and diagnosis kits of coronavirus that are urgently required. Therapeutics are based on nanotechnology strategies as well and focus on antiviral drug design and on new nanoarchitectured vaccines. A brief overview on patented work is presented that emphasizes nanotechnology applied to coronaviruses. Finally, some comments are made on patents of the initial technological responses to COVID-19 that have already been put in practice.

The COVID-19 pandemic, personal protective equipment and respirator: A narrative review

INTRODUCTION

The coronavirus disease 2019 pandemic has touched almost every continent. Personal protective equipment (PPE) is the final line of protection of healthcare workers (HCW). There is variation as well as controversy of infection control recommendation with regards to the use of PPE for HCW between institutions. The aim of this narrative review is to of examine and summarise the available evidence to guide recommendation for the safety of HCW.

METHOD

A literature search was conducted on the PubMed, MedLine and Embase databases with the keywords "personal protective equipment," "COVID 19," "n95," "health care worker" and "mortality."

RESULTS

SARS-nCoV-2 is highly contagious. About 3.5%-20% of HCW has been reported to be infected. The mortality ranges from 0.53% to 1.94%. PPE is part of the measure within a package of prevention and control of pandemic, rather than a replacement of. Respirators are more effective than masks in preventing aerosol transmission to HCWs. Extended use may be considered if guidelines are adhered. Powered air-purifying respirators if available should be used in high-risk procedures.

CONCLUSION

Transmission of viruses is multimodal and in the setting of a novel pathogen with high case fatality with no proven effective interventions, PPE that affords the best protection should be available to HCWs.

Soft matter science and the COVID-19 pandemic

Much of the science underpinning the global response to the COVID-19 pandemic lies in the soft matter domain. Coronaviruses are composite particles with a core of nucleic acids complexed to proteins surrounded by a protein-studded lipid bilayer shell. A dominant route for transmission is via air-borne aerosols and droplets. Viral interaction with polymeric body fluids, particularly mucus, and cell membranes controls their infectivity, while their interaction with skin and artificial surfaces underpins cleaning and disinfection and the efficacy of masks and other personal protective equipment. The global response to COVID-19 has highlighted gaps in the soft matter knowledge base. We survey these gaps, especially as pertaining to the transmission of the disease, and suggest questions that can (and need to) be tackled, both in response to COVID-19 and to better prepare for future viral pandemics.

Quantitation of Risk Reduction of E. coli Transmission After Using Antimicrobial Hand Soap

Handwashing with soap is an effective and economical means to reduce the likelihood of Escherichia coli infection from indirect contact with contaminated surfaces during food preparation. The purpose of this study was to conduct a quantitative microbial risk assessment (QMRA) to evaluate the risk of infection from indirect contact with fomites contaminated with E. coli after hand washing with antimicrobial hand soaps. A Monte Carlo simulation was done with a total of 10,000 simulations to compare the effectiveness of two antimicrobial and one control (non-antimicrobial) bar soaps in reducing the exposure and infection risk compared to no hand washing. The numbers of E. coli on several fomites commonly found in household kitchens, as well as the transfer rates between fomites and onto fingertips, were collected from the literature and experimental data. The sponsor company provided the E. coli survival on hands after washing with antimicrobial and control soaps. A number of scenarios were evaluated at two different exposure doses (high and low). Exposure scenarios included transfer of E. coli between meat-to-cutting board surface-to-hands, meat-to-knife surface-to-hands, and from a countertop surface-to-hands, kitchen sponge-to-hands, hand towel-to-hands, and dishcloth-to-hands. Results showed that the risks of illness after washing with the control soap was reduced approximately 5-fold compared to no handwashing. Washing with antimicrobial soap reduced the risk of E. coli infection by an average of about 40-fold compared with no handwashing. The antimicrobial soaps ranged from 3 to 32 times more effective than the non-antimicrobial soap, depending on the specific exposure scenario. Importance: The Centers for Disease Control and Prevention indicate the yearly incidence rate of Shiga Toxin producing E. coli infections is about 1.7/100,000, with about 10% of cases leading to life-threatening hemolytic uremic syndrome and 3–5% leading to death. Our findings confirm handwashing with soap reduces the risks associated with indirect transmission of E. coli infection from contact with fomites during food preparation. Further, in these exposure scenarios, antimicrobial soaps were more effective overall than the non-antimicrobial soap in reducing exposure to E. coli and risk of infection.

Development of a silver-based dual-function antimicrobial laundry additive and textile coating for the decontamination of healthcare laundry

AIMS

To repurpose a silver-based antimicrobial textile coating product (Micro-Fresh 1911) as a dual-function antimicrobial laundry additive and textile coating.

METHODS AND RESULTS

Survival of Escherichia coli or Staphylococcus aureus type and clinical isolates in a domestic 40°C wash was assessed with and without soiling and biological detergent. Washing with 2% w/v silver additive (wash phase) reduced E. coli and S. aureus by 7·14-8·08 log₁₀ and no cross-contamination was observed. Under dirty conditions, 0·5% silver additive in the rinse phase of a wash with biological detergent reduced E. coli and S. aureus by 7·98-8·40 log₁₀ (0·00-1·42 log₁₀ cross contamination). BS EN ISO 20645:2004 and BS EN ISO 20743:2013 methods were used to assess the antimicrobial activity of polycotton washed with 2% w/v silver additive against S. aureus and E. coli. The treated polycotton was antimicrobial against E. coli and S. aureus type and clinical isolates and remains active after at least one further wash cycle at 40 or 73°C.

CONCLUSIONS

The silver additive exhibits antimicrobial activity in a 40°C domestic wash, preventing cross contamination onto clean textiles and depositing an antimicrobial coating onto polycotton.

SIGNIFICANCE AND IMPACT OF THE STUDY

The survival of micro-organisms on healthcare uniforms during domestic laundering presents a potential risk of contaminating the home, cross-contamination of other clothing within the wash and transmitting potential pathogens back into healthcare settings via contaminated uniforms. Silver may be useful as an antimicrobial laundry additive to decontaminate healthcare laundry washed at low temperatures in domestic and industrial settings, to therefore reduce the potential risk of transmitting micro-organisms within the domestic and clinical environments.

Retention of E. coli and water on the skin after liquid contact

The frequent contact people have with liquids containing pathogenic microorganisms provides opportunities for disease transmission. In this work, we quantified the transfer of bacteria-using E. coli as a model- from liquid to skin, estimated liquid retention on the skin after different contact activities (hand immersion, wet-cloth and wet-surface contact), and estimated liquid transfer following hand-to-mouth contacts. The results of our study show that the number of E. coli transferred to the skin per surface area (n [E. coli/cm2]) can be modeled using n = C (10-3.38+h), where C [E. coli/cm3] is the concentration of E. coli in the liquid, and h [cm] is the film thickness of the liquid retained on the skin. Findings from the E. coli transfer experiments reveal a significant difference between the transfer of E. coli from liquid to the skin and the previously reported transfer of viruses to the skin. Additionally, our results demonstrate that the time elapsed since the interaction significantly influences liquid retention, therefore modulating the risks associated with human interaction with contaminated liquids. The findings enhance our understanding of liquid-mediated disease transmission processes and provide quantitative estimates as inputs for microbial risk assessments.

The impact of comprehensive air purification on patient duration of stay, discharge outcomes, and health care economics: A retrospective cohort study

BACKGROUND

Infectious airborne and surface pathogens constitute a substantial and poorly explored source of patient subclinical illness and infections. With that in mind, a system of advanced air purification technology was designed to destroy the DNA and RNA of all bacteria, fungi, and viruses. This study compares the effects of advanced air purification technology versus high efficiency particulate air filtration with respect to certain metrics of health care economics and resource utilization at a large, community-based, urban hospital. Our hypothesis was that the use of the advanced air purification technology would decrease health care durations of stay, lead to fewer nonhome discharges, and decrease hospital charges.

METHODS

After the installation of advanced air purification technology, 3 resultant air purification "zones" were established: zone C, a control floor with high efficiency particulate air filtration; zone B, a mixed high efficiency particulate air and advanced air purification technology floor; and zone A, a comprehensive advanced air purification technology remediation. This study included nonbariatric surgical patients admitted to any zone between December 2017 and December 2018, with reported case mix index on discharge. We analyzed hospital duration of stays, discharge destination, and hospital charges with adjustment for severity of illness using the case mix index. The likelihood of mortality, health care-associated infection, and readmission for each study zone was examined using logistic regression adjusting for case mix index, age, sex, and source of admission.

RESULTS

The study included 1,002 patients across the 3 zones, with mean age of 55.8 years (53.7% female), average case mix index of 1.98, and mortality of 1.7%. Compared with zone C, patients in zones A and B demonstrated decreased hospital stays, a greater percentage of home discharges (86.5-87.8% vs 64.7%), and less hospital charges. In addition, logistic regression modeling performed on 999 study patients showed that the likelihood of mortality, hospital-acquired infections, and readmissions did not differ among the 3 zones. A trend toward a lesser incidence of hospital-acquired infections was noted in zones A and B (0.40% and 0.48%, respectively) when compared with zone C (0.63%).

CONCLUSION

Patients in the advanced air purification technology zones demonstrated statistically significant improvements in durations of stay, discharge to home, and costs after adjusting for case mix index. In addition, a trend toward fewer hospital-acquired infections in advanced air purification technology zones was noted. These findings suggest that environmental factors may affect key clinical and economic outcomes, supporting further research in this important and largely unexplored area.

Bacterial transfer to fingertips during sequential surface contacts with and without gloves

Bacterial transmission from contaminated surfaces via hand contact plays a critical role in disease spread. However, the fomite-to-finger transfer efficiency of microorganisms during multiple sequential surface contacts with and without gloves has not been formerly investigated. We measured the quantity of Escherichia coli on fingertips of participants after 1-8 sequential contacts with inoculated plastic coupons with and without nitrile gloves. A Bayesian approach was used to develop a mechanistic model of pathogen accretion to examine finger loading as a function of the difference between E coli on surfaces and fingers. We used the model to determine the coefficient of transfer efficiency (λ), and influence of swabbing efficiency and finger area. Results showed that λ for bare skin was higher (49%, 95% CI = 32%-72%) than for gloved hands (30%, CI = 17%-49%). Microbial load tended toward a dynamic equilibrium after four and six contacts for gloved hands and bare skin, respectively. Individual differences between volunteers' hands had a negligible effect compared with use of gloves (P < .01). Gloves reduced loading by 4.7% (CI = -12%-21%) over bare skin contacts, while 20% of participants accrued more microorganisms on gloved hands. This was due to poor fitting, which created a larger finger surface area than bare hands.

The role of textiles as fomites in the healthcare environment: a review of the infection control risk

BACKGROUND

Infectious diseases are a significant threat in both healthcare and community settings. Healthcare associated infections (HCAIs) in particular are a leading cause of complications during hospitalisation. Contamination of the healthcare environment is recognised as a source of infectious disease yet the significance of porous surfaces including healthcare textiles as fomites is not well understood. It is currently assumed there is little infection risk from textiles due to a lack of direct epidemiological evidence. Decontamination of healthcare textiles is achieved with heat and/or detergents by commercial or in-house laundering with the exception of healthcare worker uniforms which are laundered domestically in some countries. The emergence of the COVID-19 pandemic has increased the need for rigorous infection control including effective decontamination of potential fomites in the healthcare environment. This article aims to review the evidence for the role of textiles in the transmission of infection, outline current procedures for laundering healthcare textiles and review studies evaluating the decontamination efficacy of domestic and industrial laundering.

METHODOLOGY

Pubmed, Google Scholar and Web of Science were searched for publications pertaining to the survival and transmission of microorganisms on textiles with a particular focus on the healthcare environment.

RESULTS

A number of studies indicate that microorganisms survive on textiles for extended periods of time and can transfer on to skin and other surfaces suggesting it is biologically plausible that HCAIs and other infectious diseases can be transmitted directly through contact with contaminated textiles. Accordingly, there are a number of case studies that link small outbreaks with inadequate laundering or infection control processes surrounding healthcare laundry. Studies have also demonstrated the survival of potential pathogens during laundering of healthcare textiles, which may increase the risk of infection supporting the data published on specific outbreak case studies.

CONCLUSIONS

There are no large-scale epidemiological studies demonstrating a direct link between HCAIs and contaminated textiles yet evidence of outbreaks from published case studies should not be disregarded. Adequate microbial decontamination of linen and infection control procedures during laundering are required to minimise the risk of infection from healthcare textiles. Domestic laundering of healthcare worker uniforms is a particular concern due to the lack of control and monitoring of decontamination, offering a route for potential pathogens to enter the clinical environment. Industrial laundering of healthcare worker uniforms provides greater assurances of adequate decontamination compared to domestic laundering, due to the ability to monitor laundering parameters; this is of particular importance during the COVID-19 pandemic to minimise any risk of SARS-CoV-2 transmission.

Evaluating a transfer gradient assumption in a fomite-mediated microbial transmission model using an experimental and Bayesian approach

Current microbial exposure models assume that microbial exchange follows a concentration gradient during hand-to-surface contacts. Our objectives were to evaluate this assumption using transfer efficiency experiments and to evaluate a model's ability to explain concentration changes using approximate Bayesian computation (ABC) on these experimental data. Experiments were conducted with two phages (MS2, ΦX174) simultaneously to study bidirectional transfer. Concentrations on the fingertip and surface were quantified before and after fingertip-to-surface contacts. Prior distributions for surface and fingertip swabbing efficiencies and transfer efficiency were used to estimate concentrations on the fingertip and surface post contact. To inform posterior distributions, Euclidean distances were calculated for predicted detectable concentrations (log₁₀ PFU cm⁻²) on the fingertip and surface post contact in comparison with experimental values. To demonstrate the usefulness of posterior distributions in calibrated model applications, posterior transfer efficiencies were used to estimate rotavirus infection risks for a fingertip-to-surface and subsequent fingertip-to-mouth contact. Experimental findings supported the transfer gradient assumption. Through ABC, the model explained concentration changes more consistently when concentrations on the fingertip and surface were similar. Future studies evaluating microbial transfer should consider accounting for differing fingertip-to-surface and surface-to-fingertip transfer efficiencies and extend this work for other microbial types.

COVID-19 and Keeping Clean: A Narrative Review To Ascertain the Efficacy of Personal Protective Equipment To Safeguard Health Care Workers Against SARS-CoV-2

Identifying the optimal amount of personal protective equipment (PPE) is a formidable challenge when faced with a new contagion such as severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Unequivocally, there are dangers to health care workers (and by extension, their patients, colleagues, and communities) if not enough equipment is donned to safeguard them. And yet, there are also dangers to patients, colleagues, and the community if resources are overconsumed and result in hoarding, shortages, and inequitable distribution, all of which are occurring as the worldwide coronavirus disease 2019 (COVID-19) pandemic continues.Research to ascertain the precise PPE required to defend specifically against SARS-CoV-2 encompasses an area of active investigation that will likely remain unresolved for some time. While awaiting more definitive conclusions, we must look to past evidence to provide a reasonable basis on which protocols and policies might be refined. What follows is a narrative review of PPE efficacy and how existing evidence might apply to protecting health care workers against COVID-19. Findings are extrapolated from investigations in 4 general domains: early investigations into SARS-CoV-2, retrospective studies about severe acute respiratory syndrome coronavirus 1, prospective studies of influenza and other common respiratory viruses, and laboratory PPE studies.Available evidence suggests that contact and droplet precautions, in addition to eye protection and standard hygiene measures, should be adequate in the vast majority of clinical settings when caring for patients with SARS-CoV-2. Adherence to guidelines promoting appropriate levels of PPE should safeguard practitioners while mitigating against resource overuse.