Ethanol and isopropanol inactivation of human coronavirus on hard surfaces

Efficacy of Three Antimicrobials Against two SARS-COV-2 Surrogates, Bovine Coronavirus and Human Coronavirus OC43, on Hard or Soft Nonporous Materials

The efficacy of three antimicrobials was evaluated against two severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) surrogates - bovine coronavirus (BCoV) and human coronavirus (HCoV) OC43 - on hard and soft nonporous materials. Three antimicrobials with three different active ingredients (chlorine, hydrogen peroxide, and quaternary ammonium compound + alcohol) were studied. Initially, a neutralization method was optimized for each antimicrobial. Then, we determined their efficacy against BCoV and HCoV OC43 in both suspension and on surfaces made with polyethylene terephthalate (PET) plastic and vinyl upholstery fabric. All tests were conducted under ambient environmental conditions with a soil load of 5% fetal bovine serum. After a 2-min exposure, all three antimicrobials achieved a >3.0 log10 reduction in viral titers in suspension. All three also reduced virus infectivity on both surface materials below the detection limit (0.6 log10 TCID50/carrier). Treatments in which the reduction in virus titer was <3.0 log10 were attributed to a decreased dynamic range on the carrier during drying prior to disinfection. The carrier data revealed that both surrogates were inactivated more rapidly (p <0.05) on vinyl or under conditions of high relative humidity. Three classes of antimicrobials were efficacious against both SARS-CoV-2 surrogate viruses, with BCoV demonstrating slightly less sensitivity compared to HCoV OC43. These findings also illustrate the importance of (1) optimizing the neutralization method and (2) considering relative humidity as a key factor for efficacy testing.

Influence of Process Parameters on the Efficiency of Pervaporation Pilot ECO-001 Plant for Raw Ethanol Dehydration

Pervaporation is a membrane-based process used for the separation of liquid mixtures. As this membrane process is governed by the differences in the sorption and diffusivities of separated components, close boiling mixtures and azeotropic mixtures can effectively be separated. The dehydration of ethanol is the most common application of hydrophilic pervaporation. The pilot scale properties of hydrophilic composite poly(vinyl alcohol) PVA membrane (PERVAPTM 2200) in contact with wet raw bioethanol are presented. The wet raw bioethanol was composed of ethanol (82.4-89.6 wt%), water (5.9-8.5 wt%), methanol (2.3-6.9 wt%), cyclohexane (0.2-2.4 wt%), higher alcohols (0.2-1.3 wt%), and acetaldehyde (0.004-0.030 wt%). All experiments were performed using a SULZER ECO-001 plant equipped with a 1.5 m2 membrane module. The efficiency of the dehydration process (i.e., membrane selectivity, permeate flux, degree of dehydration) was discussed as a function of the following parameters: the feed temperature, the feed composition, and the feed flow rate through the module. It was found that the low feed flow rate influenced the dehydration efficiency as the enthalpy of evaporation caused a high temperature drop in the module (around 25 °C at a feed flow rate equal to 5 kg h-1). The separation coefficient during pervaporation was in the range of 600-1200, depending on the feed composition. The increase in temperature augmented the permeation flux and shortened the time needed to reach the assumed level of dehydration. It was revealed that dehydration by pervaporation using ECO-001 pilot plant is an efficient process, allowing also to investigate the influence of various parameters on the process efficiency.

Chemical inactivation strategies for SARS-CoV-2-infected cells and organoids

Infectious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) research, conducted in high-containment laboratories, requires transferring samples to lower containment labs for downstream applications, mandating sample inactivation. Here, we present a stepwise protocol for chemical inactivation of SARS-CoV-2 virus in culture supernatants or within infected cells and organoids, using eight chemical reagents validated via plaque assays. Additionally, we describe steps for troubleshooting virus inactivation, titer calculation, and log reduction. This protocol offers valuable resources for the COVID-19 research community, providing essential tools to advance research on this virus.

Experimental evidence of effective disinfectant to control the transmission of Micropterus salmoides rhabdovirus

Micropterus salmoides rhabdovirus (MSRV) is a significant pathogen that causes high morbidity and mortality in largemouth bass, leading to enormous economic losses for largemouth bass aquaculture in China. The aim of this study was to investigate the efficacy of four disinfectants (potassium permanganate, glutaraldehyde, trichloroisocyanuric acid and povidone iodine) on MSRV, to control the infection and transmission of MSRV in largemouth bass aquaculture. The disinfectants were tested at different concentrations (5, 25, 50, 100 and 500 mg/L) prepared with distilled water for 30 min contact time, and the viral nucleic acid was quantified using qPCR and the infectivity was tested by challenge experiment. Potassium permanganate at 5-500 mg/L, glutaraldehyde at 500 mg/L, trichloroisocyanuric acid at 50-500 mg/L and povidone iodine at 500 mg/L concentration could effectively decrease the virus nucleic acid, and the survival rate of largemouth bass juveniles after challenge experiment increased significantly from 3.7% ± 6.41% to 33.33 ± 11.11% - 100%. Moreover, the minimum effective time of 5 mg/L potassium permanganate was further studied at 2, 5, 10 and 20 min contact time. The viral nucleic acid decreased significantly at 5-20 min exposure time, and the survival rate increased significantly from 7.41% ± 6.41% to 77.78 ± 11.11% - 100%. The median lethal concentration (LC50 ) values of potassium permanganate were 10.64, 6.92 and 3.7 mg/L at 24, 48 and 96 h, respectively. Potassium permanganate could be used for the control of MSRV in the cultivation process; the recommended concentration is 5 mg/L and application time should be less than 24 h. The results could be applied to provide a method to control the infection and transmission of MSRV in water, and improve the health status of largemouth bass.

A review on sterilization methods of environmental decontamination to prevent the coronavirus SARS-CoV-2 (COVID-19 virus): A new challenge towards eco-friendly solutions

In recent years, the COVID-19 pandemic is currently wreaking havoc on the planet. SARS-CoV-2, the Severe Acute Respiratory Syndrome Coronavirus, is the current term for this outbreak. Reports about this novel coronavirus have been presented since the pandemic's breakout, and they have demonstrated that it transmits rapidly from person to person, primarily by droplets in the air. Findings have illustrated that SARS-CoV-2 can survive on surfaces from hours to days. Therefore, it is essential to find practical solutions to reduce the virus's impact on human health and the environment. This work evaluated common sterilization methods that can decontaminate the environment and items. The goal is that healthcare facilities, disease prevention organizations, and local communities can overcome the new challenge of finding eco-friendly solutions. Further, a foundation of information encompassing various sterilization procedures and highlighting their limits to choose the most appropriate method to stop disease-causing viruses in the new context has been presented. The findings of this crucial investigation contribute to gaining insight into the comprehensive sterilization approaches against the coronavirus for human health protection and sustainable environmental development.

Designing 3D-Printed Mesh-Covered Fluid Collecting Racks (MFCRs) to Prevent Moisture-Related COVID-19 Sampling Interruptions in Taiwan

Background: A sampling platform (or table) set at the patient's side in a zero-exposure screening center (booth) might be used for specimen collection during public health crises such as the COVID-19 pandemic. However, repeated sanitization causes moisture problems. Such moisture problems would not only be noted by patients but also interrupt the sampling process. In this study, we aimed to develop 3D-printed mesh-covered fluid collecting racks (MFCRs) to address surface moisture problems to determine whether MFCRs can shorten the sampling time. Methods: This was an observational, descriptive, and cross-sectional study. We observed the reasons for sampling interruptions related to surface moisture problems among patients who used MFCRs or did not (April 28-30, 2022). We used a 3D printer to make an MFCR, which measured 14.5 cm in width and length and 1.0 cm in height. The MFCR allows the ethanol to drain through the mesh into the fluid collection rack below to leave a relatively dry surface on the mesh. Finally, we calculated the median time to finish sampling between MFCRs and non-MFCRs. Results: A total of 400 patients were randomly observed (using MFCRs, n = 200; non-MFCRs, n = 200). Patients in the non-MFCR group were more likely to interrupt the sampling process (n = 39, 19.5%) by noting surface moisture problems than those in the MFCR group (n = 3, 1.5%). Two of the major interruptions, "asking questions about the moist surface" (from 12% to 1%) and "slowing down their actions" (from 4.5% to 0.5%), were obviously improved by using MFCRs. Overall, the median sampling time was significantly shorter (p < 0.001) in the group using MFCRs (0.6 min) than in the group using non-MFCRs (1.5 min). The MFCRs shortened the sampling time by 60%, which might be associated with decreasing interruptions caused by surface moisture problems. Conclusions: The 3D printed MFCRs are suitable for handling surface moisture problems caused by repeated sanitizations. More importantly, the MFCRs might be associated with decreasing interruptions caused by moisture problems.

COVID-19 clinical waste reuse: A triboelectric touch sensor for IoT-cloud supported smart hand sanitizer dispenser

Earth's plastic pollution has increased due to the COVID-19 pandemic, and the world is on the doorstep of an enormous waste pandemic. The extensive use of mandatory personal protectives like masks, gloves, and PPE kits and the lack of proper waste management systems lead to a rise in the plastic pollution content of the earth. Such disposable and non-biodegradable personal protectives are thrown out to the environment after use. These distributed wastes pollute land, soil, and water bodies and effects their ecosystems. This research work establishes the concept of a waste-to-energy conversion approach to reuse COVID-19 scraps for green and sustainable development. Three-layered surgical masks and nitrile gloves were reused in this work after sterilization for energy harvesting and sensing applications by fabricating a 3D-printed contact-separation-based triboelectric nanogenerator. A piece of three-layered mask and nitrile gloves were placed inside the 3D structure as the top negative and bottom positive triboelectric materials with copper and aluminum as corresponding electrodes (MG-CS TENG). It can convert external mechanical motions into electrical energy. The maximum voltage, current, and power density obtained from the device are 50.7 V, 4.8 µA, and 6.39 µW/cm², respectively, for a mechanical force of 9 N. The harvested energy was sufficient to power small-scale electronic devices like digital tally counters, wristwatches, lumex displays, and series connected 25 LEDs. MG-CS TENG was also performed as a pedal-operated touch sensor to dispense hand sanitizer. MG-CS TENG was pedal pressed to trigger a microcontroller and control the solenoid valve's opening and closing to regulate sanitizer flow. The setup was integrated using the internet of things (IoT) and Blynk cloud services for the remote monitoring and controlling of the sanitizer dispenser using a smartphone. This work contributes a substantial role in disaster management to suppress microplastic environmental pollution by reusing pandemic wastes for energy harvesting and sensing applications and preventing the spread of coronavirus through proper hand sanitization.

Inactivation of replication-competent severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) on common surfaces by disinfectants

This experimental laboratory-based study evaluated two disinfectants' efficacy against replication-competent severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) on three surfaces. Disinfectants were effictive at eliminating the presence, viability, and subsequent replication of SARS-CoV-2 on all surfaces. Although SARS-CoV-2 likely spreads primarily via airborne transmission, layered mitigation should include high-touch surface disinfection.

Comparative efficacy evaluation of disinfectants against severe acute respiratory syndrome coronavirus-2

BACKGROUND

Disinfection is one of the most effective ways to block the rapid transmission of severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2). Due to the prolonged coronavirus disease 2019 (COVID-19) pandemic, disinfectants have become crucial to prevent person-to-person transmission and decontaminate hands, clothes, facilities and equipment. However, there is a lack of accurate information on the virucidal activity of commercial disinfectants.

AIM

To evaluate the virucidal efficacy of 72 commercially available disinfectants constituting 16 types of ingredients against SARS-CoV-2.

METHODS

SARS-CoV-2 was tested with various concentrations of disinfectants at indicated exposure time points as recommended by the manufacturers. The 50% tissue culture infectious dose assay was used to calculate virus titre, and trypan blue staining and CCK-8 were used to assess cell viability after 3-5 days of SARS-CoV-2 infection.

FINDINGS

This study found that disinfectants based on 83% ethanol, 60% propanol/ethanol, 0.00108-0.0011% sodium dichloroisocyanurate and 0.497% potassium peroxymonosulfate inactivated SARS-CoV-2 effectively and safely. Although disinfectants based on 0.05-0.4% benzalkonium chloride (BAC), 0.02-0.07% quaternary ammonium compound (QAC; 1:1), 0.4% BAC/didecyldimethylammonium chloride (DDAC), 0.28% benzethonium chloride concentrate/2-propanol, 0.0205-0.14% DDAC/polyhexamethylene biguanide hydrochloride (PHMB) and 0.5% hydrogen peroxide inactivated SARS-CoV-2 effectively, they exhibited cytotoxicity. Conversely, disinfectants based on 0.04-4% QAC (2:3), 0.00625% BAC/DDAC/PHMB, and 0.0205-0.14% and 0.0173% peracetic acid showed approximately 50% virucidal efficacy with no cytotoxicity. Citric acid (0.4%) did not inactivate SARS-CoV-2.

CONCLUSION

These results indicate that most commercially available disinfectants exert a disinfectant effect against SARS-CoV-2. However, re-evaluation of the effective concentration and exposure time of certain disinfectants is needed, especially citric acid and peracetic acid.

Mental and physical health correlates of the psychological impact of the first wave of COVID-19 among general population of Pakistan

The primary aim was to assess the role of mental and physical health of COVID-19 and its psychological impact in the general population of Pakistan during the first wave of COVID-19. It was hypothesized that there would be a significant predictive association among socio-demographic variables, psychological impact and mental health status resulting from COVID-19, and poor self-reported physical health would be significantly associated with adverse psychological impact and poor mental health status because of COVID-19. A cross-sectional survey research design was used in which 1,361 respondents were sampled online during lockdown imposed in the country. The Impact of Events Scale-Revised (IES-R) was used to assess the psychological impact of COVID-19, and the Depression Anxiety Stress Scales (DASS-21) was used to assess participants’ mental health status. 18% of the respondents reported moderate to severe event-specific distress, 22.6% reported moderate to severely extreme depression, 29% reported moderate to extreme anxiety, and 12.1% reported moderate to extreme stress. Female gender, having graduate-level education, currently studying, and self-reported physical symptoms (persistent fever, chills, headache, cough, breathing difficulty, dizziness, and sore throat) were significantly associated with higher levels of psychological impact exhibited through higher scores on the IES-R and poorer mental health status exhibited through higher scores on the DASS-21 (Depression, Anxiety, and Stress Subscales).

Japanese Knotweed Rhizome Bark Extract Inhibits Live SARS-CoV-2 In Vitro

Coronavirus disease 2019 (COVID-19), a viral infectious respiratory disease, is caused by highly contagious severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and is responsible for the ongoing COVID-19 pandemic. Since very few drugs are known to be effective against SARS-CoV-2, there is a general need for new therapeutics, including plant-based drugs, for the prophylaxis and treatment of infections. In the current study, the activity of a 70% ethanolic(aq) extract of the rhizome bark of Japanese knotweed, an invasive alien plant species, was tested for the first time against the wild-type SARS-CoV-2 virus using a specific and robust virus neutralization test (VNT) on Vero-E6 cells, which best mimics the mechanism of real virus−host interaction. A statistically significant antiviral effect against SARS-CoV-2 (p-value < 0.05) was observed for the 50.8 µg mL−1 extract solution in cell medium. A suitable extract preparation was described to avoid loss of polyphenols throughout filtration of the extract, which was dissolved in cell medium containing fetal bovine serum (FBS). The significance of the differences between the sums of the test and control groups in the incidence of cytopathic effects (CPE) was determined using the one-way ANOVA test. A dose−response relationship was observed, with the cytotoxic effect occurring at higher concentrations of the extract (≥101.6 µg mL−1). The obtained results suggest possible use of this plant material for the production of various products (e.g., packaging, hygiene products, biodisinfectants, etc.) that would be useful against the spread of and for self-protection against COVID-19.

Predicting attitudinal and behavioral responses to COVID-19 pandemic using machine learning

At the beginning of 2020, COVID-19 became a global problem. Despite all the efforts to emphasize the relevance of preventive measures, not everyone adhered to them. Thus, learning more about the characteristics determining attitudinal and behavioral responses to the pandemic is crucial to improving future interventions. In this study, we applied machine learning on the multinational data collected by the International Collaboration on the Social and Moral Psychology of COVID-19 (N = 51,404) to test the predictive efficacy of constructs from social, moral, cognitive, and personality psychology, as well as socio-demographic factors, in the attitudinal and behavioral responses to the pandemic. The results point to several valuable insights. Internalized moral identity provided the most consistent predictive contribution-individuals perceiving moral traits as central to their self-concept reported higher adherence to preventive measures. Similar results were found for morality as cooperation, symbolized moral identity, self-control, open-mindedness, and collective narcissism, while the inverse relationship was evident for the endorsement of conspiracy theories. However, we also found a non-neglible variability in the explained variance and predictive contributions with respect to macro-level factors such as the pandemic stage or cultural region. Overall, the results underscore the importance of morality-related and contextual factors in understanding adherence to public health recommendations during the pandemic.

Investigation of mouse hepatitis virus strain A59 inactivation under both ambient and cold environments reveals the mechanisms of infectivity reduction following UVC exposure

The surface contamination of SARS-CoV-2 is becoming a potential source of virus transmission during the pandemic of COVID-19. Under the cold environment, the infection incidents would be more severe with the increase of virus survival time. Thus, the disinfection of contaminated surfaces in both ambient and cold environments is a critical measure to restrain the spread of the virus. In our study, it was demonstrated that the 254 nm ultraviolet-C (UVC) is an efficient method to inactivate a coronavirus, mouse hepatitis virus strain A59 (MHV-A59). The inactivation rate to MHV-A59 coronavirus was up to 99.99% when UVC doses were 2.90 and 14.0 mJ/cm² at room temperature (23 °C) and in cold environment (-20 °C), respectively. Further mechanistic study demonstrated that UVC could induce spike protein damage to partly impede virus attachment and genome penetration processes, which contributes to 12% loss of viral infectivity. Additionally, it can induce genome damage to significantly interrupt genome replication, protein synthesis, virus assembly and release processes, which takes up 88% contribution to viral inactivation. With these mechanistic understandings, it will greatly contribute to the prevention and control of the current SARS-CoV-2 transmissions in cold chains (low temperature-controlled product supply chains), public area such as airport, school, and warehouse.

Optimization of COVID-19 face mask waste fibers and silica fume as a balanced mechanical ameliorator of fat clay using response surface methodology

The balanced amelioration of mechanical characteristics of fat clay with an additive refers to the attainment of high strength without compromising ductility, which is unattainable by solitary usage of a cementing additive. For this purpose, an amalgamated binary admixture (ABA) is proposed by assimilating shredded face mask (FM) waste, which is posing serious environmental concerns these days, with a cementitious waste material, i.e., silica fume (SF). However, for such ABA, the optimization of mix design is desirable because an excessive amount of one component could disturb the required balance. To address this issue, response surface methodology (RSM) is used in the current study, which is a strong technique used during the process of production to develop, improve, and optimize product inputs. Several experiments are designed and conducted to evaluate mechanical responses, i.e., unconfined compressive strength (qu), brittleness index (IB), deformability index (ID), and California bearing ratio (CBR) value, of treated fat clay by varying mix designs of ABA. Based on the test results, mathematical models are developed which are found to be statistically valid to predict the subjected responses using SF and FM as inputs. Afterward, an optimized mix design is determined by integrating developed models with a desirability function model and setting maximization of strength and ductility as the optimization goals. An ABA having 7.9% SF and 1.2% FM is observed to provide the highest strength and ductility for multiple applications, i.e., road and buildings, with desirability factor close to unity; responses of which are also validated by performing tests. Furthermore, analysis of cleaning aspect shows that the use of optimized ABA in place of cement for subgrade improvement of 1 km two-lane road could avoid CO2 emission of around 79,032 kg of C, save 42,720 kWh and 1174.8 GJ of electrical and thermal energy, respectively, and clean 43 Mg of FM waste; however, astute protocols of COVID-19 FM waste handling and disinfection are needed to be established and followed.

Breath collection protocol for SARs-CoV-2 testing in an ambulatory setting

Breath research during the SARS-CoV-2 pandemic offers an opportunity for discovery of a rapid point-of-care screening test, but also introduces a hazard to researchers collecting, transporting and analyzing breath samples not only for COVID -19 research, but all human breath-related research during the ongoing pandemic. Safe workflows to protect study participants and staff collecting and analysing the samples must be determined. We developed a SARS-CoV-2 breath test protocol for collection and processing of breath samples in ambulatory care COVID-19 testing sites and prospectively evaluated the protocol. 528 breath samples from 393 participants at COVID-19 testing sites were safely collected, transported, stored, and analysed with zero transmission to staff. Our method development for the safe collection of samples included the examination of 2 different filters for added safety. We discovered the use of filters leads to increased sample contamination and/or reduction of endogenous features in breath samples. Personal protective equipment (PPE) is essential for all breath collection while SARS-CoV-2 remains wide-spread through the general population. We have demonstrated that use of completely disposable breath collection devices and PPE, are sufficient for safe collection. Filters in the workflow add complexity to an already complex breath matrix and may compromise bio-safety.

The efficacy of different sanitizers against MS2 bacteriophage introduced onto plastic or stainless steel surfaces

The virucidal activities of 11 prepared disinfectant solutions (active ingredients of household sanitizers) and 10 household sanitizers against bacteriophage MS2 on plastic and stainless steel surfaces were studied. Among the prepared sanitizers, 70-90% ethanol and ethanol-based disinfectants resulted in 1-2.5 log PFU/mL reductions on both surfaces. The 70% isopropanol and isopropanol-based formula reduced MS2 by 0.7-1.5 log PFU/mL on both surfaces. Other disinfectants, containing 0.1% benzalkonium chloride (BAC), 0.5% hydrogen peroxide, or 4% acetic acid, showed significant (P < 0.05) lower log reductions (-0.17-0.55 log PFU/mL) compared with other treatments. At room temperature, the virucidal activities of 70% ethanol on plastic (1.46-1.64 log PFU/mL reductions) and stainless steel (0.84-0.93 log PFU/mL reductions) surfaces were not significantly (P > 0.05) affected by the treatment time (30-600 s). However, 85% ethanol-treated groups showed significant (P < 0.05) higher log reductions in 60 and 600 s treated groups (1.69-2.24 log PFU/mL) compared with those in 30 s treated groups (0.92-1.32 log PFU/mL). Their virucidal activities were further examined at low temperatures (4 and 8 °C). We observed that the surface inactivation efficacies were not affected by the low temperatures. In addition, the virucidal activities of household sanitizers revealed that sanitizers with 1.84% (pH = 12.5, ∼17,500 ppm free-chlorine concentrations) or 3% (pH = 13.1, ∼38,100 ppm free-chlorine concentrations) sodium hypochlorite (NaClO) reduced 4.15-6.23 log PFU/mL MS2 on hard surfaces after 60 s contact time. Furthermore, an approximately 1.5 log PFU/mL reduction was observed in groups treated by sanitizer H (active ingredients: 58% ethanol + 0.1% quaternary ammonium compound). Household products with BAC or organic acid resulted in -0.28-0.33 log reductions on two surfaces after 30 or 60 s treatment. Therefore, the use of ethanol and NaClO-based products should be considered as a potential surface decontamination strategy in the food industry.

Essential Oil Disinfectant Efficacy Against SARS-CoV-2 Microbial Surrogates

Reports of COVID-19 cases potentially attributed to fomite transmission led to the extensive use of various disinfectants to control viral spread. Alternative disinfectants, such as essential oils, have emerged as a potential antimicrobial. Four essential oil blends were tested on three different surfaces inoculated with a coronavirus surrogate, bacteriophage Phi 6, and a bacterial indicator, Staphylococcus aureus. Log10 concentration reductions were analyzed using GraphPad Prism software. Data collected in this study show that the application of dilute essential oil disinfectants using a spray delivery device is an effective way to reduce concentrations of bacterial and viral microorganisms on ceramic, stainless steel, and laminate surfaces. Surrogate viruses were reduced up to 6 log10 PFU and bacterial were reduced up to 4 log10 CFU. Although surfaces are no longer considered a high risk fomite for COVID-19 transmission, the disinfection of microorganisms on surfaces remains an important consideration for high touch areas in hospitals, waiting rooms, etc. The application of spray disinfectants, based on essential oil blends, provides a rapid and effective means to reduce microbial contamination on high-touched surfaces.

Antiviral and antibacterial activity of hand sanitizer and surface disinfectant formulations

Emergent diseases caused by viral and bacterial infections have proven to be a current and future challenge. The occurrence of these diseases is usually accompanied by the lack of vaccines and dedicated therapies leaving prevention as the best strategy to adopt. In that context, and apart from confinement and physical distancing measures, an increase in hygiene actions, namely hand and surface cleaning and disinfection can reduce the infection spread originated from our day-to-day routines. However, during crisis situations the high disinfectants demand can very likely lead to having them running out of stock. This impels many individuals and companies to produce their own disinfectants. Here, we explore the main components of a disinfection formulation, both for hand-rub and surface cleaning. Alcohol and non-alcohol based formulations are described, including the possibility to fine tune the properties of the final product in order to increase public acceptance while maintaining product efficacy. The action mechanisms of the main active principles are also described conjugating information from experimental and theoretical data. Overall, the main aspects to develop a disinfectant formulation are addressed, as well as their function, helping formulation developers to better understand the impact of their choices.

Ethanol-based disinfectant sprays drive rapid changes in the chemical composition of indoor air in residential buildings

The COVID-19 pandemic has resulted in increased usage of ethanol-based disinfectants for surface inactivation of SARS-CoV-2 in buildings. Emissions of volatile organic compounds (VOCs) and particles from ethanol-based disinfectant sprays were characterized in real-time (1 Hz) via a proton transfer reaction time-of-flight mass spectrometer (PTR-TOF-MS) and a high-resolution electrical low-pressure impactor (HR-ELPI+), respectively. Ethanol-based disinfectants drove sudden changes in the chemical composition of indoor air. VOC and particle concentrations increased immediately after application of the disinfectants, remained elevated during surface contact time, and gradually decreased after wiping. The disinfectants produced a broad spectrum of VOCs with mixing ratios spanning the sub-ppb to ppm range. Ethanol was the dominant VOC emitted by mass, with concentrations exceeding 103 μg m-3 and emission factors ranging from 101 to 102 mg g-1. Listed and unlisted diols, monoterpenes, and monoterpenoids were also abundant. The pressurized sprays released significant quantities (104-105 cm-3) of nano-sized particles smaller than 100 nm, resulting in large deposited doses in the tracheobronchial and pulmonary regions of the respiratory system. Inhalation exposure to VOCs varied with time during the building disinfection events. Much of the VOC inhalation intake (>60 %) occurred after the disinfectant was sprayed and wiped off the surface. Routine building disinfection with ethanol-based sprays during the COVID-19 pandemic may present a human health risk given the elevated production of volatile chemicals and nano-sized particles.

Viral Inactivation Impacts Microbiome Estimates in a Tissue-Specific Manner

The global emergence of novel pathogenic viruses presents an important challenge for research, as high biosafety levels are required to process samples. While inactivation of infectious agents facilitates the use of less stringent safety conditions, its effect on other biological entities of interest present in the sample is generally unknown. Here, we analyzed the effect of five inactivation methods (heat, ethanol, formaldehyde, psoralen, and TRIzol) on microbiome composition and diversity in samples collected from four different body sites (gut, nasal, oral, and skin) and compared them against untreated samples from the same tissues. We performed 16S rRNA gene sequencing and estimated abundance and diversity of bacterial taxa present in all samples. Nasal and skin samples were the most affected by inactivation, with ethanol and TRIzol inducing the largest changes in composition, and heat, formaldehyde, TRIzol, and psoralen inducing the largest changes in diversity. Oral and stool microbiomes were more robust to inactivation, with no significant changes in diversity and only moderate changes in composition. Firmicutes was the taxonomic group least affected by inactivation, while Bacteroidetes had a notable enrichment in nasal samples and moderate enrichment in fecal and oral samples. Actinobacteria were more notably depleted in fecal and skin samples, and Proteobacteria exhibited a more variable behavior depending on sample type and inactivation method. Overall, our results demonstrate that inactivation methods can alter the microbiome in a tissue-specific manner and that careful consideration should be given to the choice of method based on the sample type under study. IMPORTANCE Understanding how viral infections impact and are modulated by the microbiome is an important problem in basic research but is also of high clinical relevance under the current pandemic. To facilitate the study of interactions between microbial communities and pathogenic viruses under safe conditions, the infectious agent is generally inactivated prior to processing samples. The effect of this inactivation process in the microbiome is, however, unknown. Further, it is unclear whether biases introduced by inactivation methods are dependent on the sample type under study. Estimating the magnitude and nature of the changes induced by different methods in samples collected from various body sites thus provides important information for current and future studies that require inactivation of pathogenic agents.

Disinfection methods against SARS-CoV-2: a systematic review

Background

Severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), the causative agent of coronavirus disease 2019, has caused millions of deaths worldwide. The virus is transmitted by inhalation of infectious particles suspended in the air, direct deposition on mucous membranes and indirect contact via contaminated surfaces. Disinfection methods that can halt such transmission are important in this pandemic and in future viral infections.

Aim

To highlight the efficacy of several disinfection methods against SARS-CoV-2 based on up-to-date evidence found in the literature.

Methods

Two databases were searched to identify studies that assessed disinfection methods used against SARS-CoV-2. In total, 1229 studies were identified and 60 of these were included in this review. Quality assessment was evaluated by the Office of Health Assessment and Translation's risk-of-bias tool.

Findings

Twenty-eight studies investigated disinfection methods on environmental surfaces, 16 studies investigated disinfection methods on biological surfaces, four studies investigated disinfection methods for airborne coronavirus, and 16 studies investigated methods used to recondition personal protective equipment (PPE).

Conclusions

Several household and hospital disinfection agents and ultraviolet-C (UV-C) irradiation were effective for inactivation of SARS-CoV-2 on environmental surfaces. Formulations containing povidone-iodine can provide virucidal action on the skin and mucous membranes. In the case of hand hygiene, typical soap bars and alcohols can inactivate SARS-CoV-2. Air filtration systems incorporated with materials that possess catalytic properties, UV-C devices and heating systems can reduce airborne viral particles effectively. The decontamination of PPE can be conducted safely by heat and ozone treatment.

Efficacy of frontline chemical biocides and disinfection approaches for inactivating SARS-CoV-2 variants of concern that cause coronavirus disease with the emergence of opportunities for green eco-solutions

The emergence of severe acute respiratory disease (SARS-CoV-2) variants that cause coronavirus disease is of global concern. Severe acute respiratory disease variants of concern (VOC) exhibiting greater transmissibility, and potentially increased risk of hospitalization, severity and mortality, are attributed to molecular mutations in outer viral surface spike proteins. Thus, there is a reliance on using appropriate counter-disease measures, including non-pharmaceutical interventions and vaccination. The best evidence suggests that the use of frontline biocides effectively inactivate coronavirus similarly, including VOC, such as 202012/01, 501Y.V2 and P.1 that have rapidly replaced the wild-type variant in the United Kingdom, South Africa and Brazil, respectively. However, this review highlights that efficacy of VOC-disinfection will depend on the type of biocide and the parameters governing the activity. VOC are likely to be similar in size to the wild-type strain, thus implying that existing guidelines for use and re-use of face masks post disinfection remain relevant. Monitoring to avoid injudicious use of biocides during the coronavirus disease era is required as prolonged and excessive biocide usage may negatively impact our receiving environments; thus, highlighting the potential for alternative more environmental-friendly sustainable biocide solutions. Traditional biocides may promote cross-antimicrobial resistance to antibiotics in problematical bacteria. The existing filtration efficacy of face masks is likely to perform similarly for VOC due to similar viral size; however, advances in face mask manufacturing by way incorporating new anti-viral materials will potentially enhance their design and functionality for existing and potential future pandemics.

Impact of the Coronavirus on Providing Oral Health Care in the Netherlands

OBJECTIVE

Transmission of SARS-CoV-2 during oral health care is potentially increased compared to regular social activities. Specific amendments to the Dutch national infection control guidelines were promulgated. This study aimed to map the impact of the coronavirus pandemic on providing oral health care during the first wave of the coronavirus pandemic in 2020 in the Netherlands.

METHODS

A cross-sectional web-based survey was sent via email to a representative sample of dental hygienists and dentists in the Netherlands.

RESULTS

Of the 1700 oral health care practitioners approached, 440 (25.9%) responded to the survey. Patient access to oral health care was severely restricted during the lockdown in the spring of 2020. A total of 1.6% of the oral health care practitioners had laboratory-confirmed COVID-19 during the study period, although this is likely to be an underrepresentation due to limited access to testing at that time. Over half of the participants perceived an increased risk of virus transmission during aerosol-generating treatments in their practices. A large majority (65.0%-87.1%) of the oral health care practitioners followed the COVID-19-specific amendments to the national infection control guidelines. Compared to the pre-pandemic period, additional personal protective equipment and protocols were applied. Factors related with compliance with the additional recommendations were age, employment status, and occupation.

CONCLUSIONS

The pandemic had a profound impact on both the accessibility and practice of oral health care. This survey study found that most Dutch oral health care practitioners paid extra attention to hygiene and infection control. Also, a low number of COVID-19 infections detected amongst Dutch oral health care practitioners was reported in the Netherlands. These overall outcomes suggest that safe oral health care can be provided when following the current infection control recommendations.

Transmission of SARS-CoV-2 considering shared chairs in outpatient dialysis: a real-world case-control study

BACKGROUND

SARS-CoV-2 can remain transiently viable on surfaces. We examined if use of shared chairs in outpatient hemodialysis associates with a risk for indirect patient-to-patient transmission of SARS-CoV-2.

METHODS

We used data from adults treated at 2,600 hemodialysis facilities in United States between February 1st and June 8th, 2020. We performed a retrospective case-control study matching each SARS-CoV-2 positive patient (case) to a non-SARS-CoV-2 patient (control) treated in the same dialysis shift. Cases and controls were matched on age, sex, race, facility, shift date, and treatment count. For each case-control pair, we traced backward 14 days to assess possible prior exposure from a 'shedding' SARS-CoV-2 positive patient who sat in the same chair immediately before the case or control. Conditional logistic regression models tested whether chair exposure after a shedding SARS-CoV-2 positive patient conferred a higher risk of SARS-CoV-2 infection to the immediate subsequent patient.

RESULTS

Among 170,234 hemodialysis patients, 4,782 (2.8 %) tested positive for SARS-CoV-2 (mean age 64 years, 44 % female). Most facilities (68.5 %) had 0 to 1 positive SARS-CoV-2 patient. We matched 2,379 SARS-CoV-2 positive cases to 2,379 non-SARS-CoV-2 controls; 1.30 % (95 %CI 0.90 %, 1.87 %) of cases and 1.39 % (95 %CI 0.97 %, 1.97 %) of controls were exposed to a chair previously sat in by a shedding SARS-CoV-2 patient. Transmission risk among cases was not significantly different from controls (OR = 0.94; 95 %CI 0.57 to 1.54; p = 0.80). Results remained consistent in adjusted and sensitivity analyses.

CONCLUSIONS

The risk of indirect patient-to-patient transmission of SARS-CoV-2 infection from dialysis chairs appears to be low.

Inactivation of Coronaviruses during Sample Preparation for Proteomics Experiments

Mass spectrometry-based proteomics is applied in SARS-CoV-2 research and is, moreover, being discussed as a novel method for SARS-CoV-2 diagnostics. However, the safe inactivation of coronaviruses by proteomics lysis buffers has not been systematically analyzed yet. Hence, for safety reasons a heating step prior to sample preparation is often performed. This step could be omitted once the safe inactivation with the typical buffers is proven. Here we test five different proteomics lysis buffers-4% SDS, 1% SDC, TFA, 6 M GdmCl, and 8 M urea-for their inactivation capacity of coronaviruses. Two representative human coronaviruses, namely HCoV-229E and HCoV-OC43, were used as surrogate for SARS-CoV-2. Lysis was performed at room temperature and at 95 °C for 5 min. Inactivation was confirmed by the absence of a cytopathic effect in MRC-5 cells, and equivocal results were further confirmed by serial passaging and quantitative real-time PCR. While at room temperature SDS, SDC, and TFA inactivated both coronaviruses, and GdmCl and urea resulted in partially incomplete inactivation. This demonstrates that care should be taken when choosing lysis buffers for proteomics analysis of coronaviruses, because some buffers do not ensure inactivation and, hence, biosafety during the further sample preparation.

Novel 3D printable powered air purifying respirator for emergency use during PPE shortage of the COVID-19 pandemic: a study protocol and device safety analysis

OBJECTIVES

To design a low-cost 3D printable powered air-purifying respirator (PAPR) that meets National Institute for Occupational Safety and Health (NIOSH) standard for flow rate and Occupational Safety and Health Administration (OSHA) standard for particle filtration for loose-fitting PAPRs and that can be made with a 3D printer and widely available materials.

DESIGN

Detailed description of components, assembly instructions and testing of a novel PAPR design in an academic laboratory following respective protocols. The assembled PAPR must meet NIOSH standards of flow rate, 170 L/min; OSHA fit factor for particle filtration, ≥250 and maintain positive pressure during regular and deep breathing.

MAIN OUTCOME MEASURES

The PAPR design was run through a series of tests: air flow (L/min), particle filtration (quantitative and qualitative) and positive pressure measured inside the helmet (mm Hg).

RESULTS

Flow rate was 443.32 L/min (NIOSH standard: minimum 170 L/min) and overall fit factor for particle filtration was 1362 (OSHA pass level: ≥500), n=1. The device passed qualitative particle filtration, n=2, and measured peak pressure of 6mm Hg (>0 mm Hg indicates positive pressure) in the helmet, n=1.

CONCLUSIONS

The Hygieia PAPR is a low-cost, easily accessible, just-in-time 3D printable PAPR design that meets minimum NIOSH and OSHA standards for flow-rate and particle filtration for loose-fitting PAPR devices to be made and used when industry-made designs are unavailable.

Analyses of Commercially Available Alcohol-Based Hand Rubs Formulated with Compliant and Non-Compliant Ethanol

The COVID-19 pandemic led to panic-buying of alcohol-based hand rubs (ABHRs). In response, governmental agencies (e.g., Health Canada) permitted the sale of ABHRs formulated with "technical-grade" ethanol to alleviate the growing demand. Technical-grade ethanol contains elevated concentrations of impurities (e.g., acetaldehyde, etc.), which may exhibit dose-dependent toxicity. In this study, a rapid solvent extraction was employed to analyze gelled ABHRs via gas chromatography with flame ionization detection. In total, 26 liquid and 16 gelled ABHRs were analyzed for nine common impurities to determine compliance with Health Canada interim guidelines. Of 42 samples analyzed, 11 ABHRs appear to be non-compliant with interim Health Canada guidelines. Non-compliant ABHRs exhibited elevated concentrations of acetaldehyde, with a maximal concentration observed of 251 ± 10 µL L-1; 3.3× higher than currently permitted. Nonetheless, frequent testing of ABHRs should be routinely conducted to reduce the risk of consumer exposure to non-compliant ABHRs.

Inactivation of Human Coronavirus by FATHHOME's Dry Sanitizer Device: Rapid and Eco-Friendly Ozone-Based Disinfection of SARS-CoV-2

The pandemic of SARS-CoV-2/COVID-19 was reported in December 2019 in Wuhan, China. Pertaining to its high transmissibility and wide host adaptability, this unique human coronavirus spread across the planet inflicting 115 million people and causing 2.5 million deaths (as of March 3rd, 2021). Limited or negligible pre-existing immunity to multiple SARS-CoV-2 variants has resulted in severe morbidity and mortality worldwide, as well as a record-breaking surge in the use of medical-surgical supplies and personal protective equipment. In response to the global need for effective sterilization techniques, this study evaluated the virucidal efficacy of FATHHOME's self-contained, ozone-based dry-sanitizing device, by dose and time response assessment. We tested inactivation of human coronavirus, HCoV-OC43, a close genetic model of SARS-CoV-2, on porous (N95 filtering facepiece respirator/FFR) and nonporous (glass) surfaces. We started our assays with 20 ppm-10 min ozone exposure, and effectively reduced 99.8% and 99.9% of virus from glass and N95 FFR surfaces, respectively. Importantly, the virus was completely inactivated, below the detection limit (over 6-log10 reduction) with 25 ppm-15 min ozone exposure on both tested surfaces. As expected, a higher ozone exposure (50 ppm-10 min) resulted in faster inactivation of HCoV-OC43 with 100% inactivation from both the surfaces, with no residual ozone present after completion of the 5-min post exposure recapture cycle and no measurable increase in ambient ozone levels. These results confirmed that FATHHOME's device is suitable for rapid decontamination of SARS-CoV-2- from worn items, frequently touched items, and PPE including N95 FFRs, face shields, and other personal items.

Transmission of SARS-CoV-2 Considering Shared Chairs in Outpatient Dialysis: A Real-World Case-Control Study

Background:

SARS-CoV-2 is primarily transmitted through aerosolized droplets; however, the virus can remain transiently viable on surfaces.

Objective:

We examined transmission within hemodialysis facilities, with a specific focus on the possibility of indirect patient-to-patient transmission through shared dialysis chairs.

Design:

We used real-world data from hemodialysis patients treated between February 1^st and June 8^th, 2020 to perform a case-control study matching each SARS-CoV-2 positive patient (case) to a non-SARS-CoV-2 patient (control) in the same dialysis shift and traced back 14 days to capture possible exposure from chairs sat in by SARS-CoV-2 patients. Cases and controls were matched on age, sex, race, facility, shift date, and treatment count.

Setting:

2,600 hemodialysis facilities in the United States.

Patients:

Adult (age ≥18 years) hemodialysis patients.

Measurements:

Conditional logistic regression models tested whether chair exposure after a positive patient conferred a higher risk of SARS-CoV-2 infection to the immediate subsequent patient.

Results:

Among 170,234 hemodialysis patients, 4,782 (2.8%) tested positive for SARS-CoV-2 (mean age 64 years, 44% female). Most facilities (68.5%) had 0 to 1 positive SARS-CoV-2 patient. We matched 2,379 SARS-CoV-2 positive cases to 2,379 non-SARS-CoV-2 controls; 1.30% (95%CI 0.90%, 1.87%) of cases and 1.39% (95%CI 0.97%, 1.97%) of controls were exposed to a chair previously sat in by a shedding SARS-CoV-2 patient. Transmission risk among cases was not significantly different from controls (OR=0.94; 95%CI 0.57 to 1.54; p=0.80). Results remained consistent in adjusted and sensitivity analyses.

Limitation:

Analysis used real-world data that could contain errors and only considered vertical transmission associated with shared use of dialysis chairs by symptomatic patients.

Conclusions:

The risk of indirect patient-to-patient transmission of SARS-CoV-2 infection from dialysis chairs appears to be low.

Primary Funding Source:

Fresenius Medical Care North America; National Institute of Diabetes and Digestive and Kidney Diseases (R01DK130067)