Your browser doesn't support javascript.
Show: 20 | 50 | 100
Results 1 - 20 de 201
Filter
Add filters

Document Type
Year range
1.
ScientificWorldJournal ; 2021: 9342748, 2021.
Article in English | MEDLINE | ID: covidwho-1495720

ABSTRACT

Background: Recently, an outbreak of a novel human coronavirus SARS-CoV-2 has become a world health concern leading to severe respiratory tract infections in humans. Virus transmission occurs through person-to-person contact, respiratory droplets, and contaminated hands or surfaces. Accordingly, we aim at reviewing the literature on all information available about the persistence of coronaviruses, including human and animal coronaviruses, on inanimate surfaces and inactivation strategies with biocides employed for chemical and physical disinfection. Method: A comprehensive search was systematically conducted in main databases from 1998 to 2020 to identify various viral disinfectants associated with HCoV and methods for control and prevention of this newly emerged virus. Results: The analysis of 62 studies shows that human coronaviruses such as severe acute respiratory syndrome (SARS) coronavirus, Middle East respiratory syndrome (MERS) coronavirus or endemic human coronaviruses (HCoV), canine coronavirus (CCV), transmissible gastroenteritis virus (TGEV), and mouse hepatitis virus (MHV) can be efficiently inactivated by physical and chemical disinfectants at different concentrations (70, 80, 85, and 95%) of 2-propanol (70 and 80%) in less than or equal to 60 s and 0.5% hydrogen peroxide or 0.1% sodium hypochlorite within 1 minute. Additionally, glutaraldehyde (0.5-2%), formaldehyde (0.7-1%), and povidone-iodine (0.1-0.75%) could readily inactivate coronaviruses. Moreover, dry heat at 56°C, ultraviolet light dose of 0.2 to 140 J/cm2, and gamma irradiation could effectively inactivate coronavirus. The WHO recommends the use of 0.1% sodium hypochlorite solution or an ethanol-based disinfectant with an ethanol concentration between 62% and 71%. Conclusion: The results of the present study can help researchers, policymakers, health decision makers, and people perceive and take the correct measures to control and prevent further transmission of COVID-19. Prevention and decontamination will be the main ways to stop the ongoing outbreak of COVID-19.


Subject(s)
COVID-19/prevention & control , Disinfectants/pharmacology , Disinfection/instrumentation , SARS-CoV-2 , Virus Inactivation/drug effects , 2-Propanol/pharmacology , Animals , COVID-19/virology , Coronavirus, Canine/drug effects , Disinfection/methods , Ethanol/pharmacology , Formaldehyde/pharmacology , Gamma Rays , Glutaral/pharmacology , Hot Temperature , Humans , Hydrogen Peroxide/pharmacology , Mice , Middle East Respiratory Syndrome Coronavirus/drug effects , Murine hepatitis virus/drug effects , Povidone-Iodine/pharmacology , SARS Virus/drug effects , Sodium Hypochlorite/pharmacology , Transmissible gastroenteritis virus/drug effects , Ultraviolet Rays
2.
Appl Environ Microbiol ; 87(22): e0153221, 2021 10 28.
Article in English | MEDLINE | ID: covidwho-1494943

ABSTRACT

Effective disinfection technology to combat severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) can help reduce viral transmission during the ongoing COVID-19 global pandemic and in the future. UV devices emitting UVC irradiation (200 to 280 nm) have proven to be effective for virus disinfection, but limited information is available for SARS-CoV-2 due to the safety requirements of testing, which is limited to biosafety level 3 (BSL3) laboratories. In this study, inactivation of SARS-CoV-2 in thin-film buffered aqueous solution (pH 7.4) was determined across UVC irradiation wavelengths of 222 to 282 nm from krypton chloride (KrCl*) excimers, a low-pressure mercury-vapor lamp, and two UVC light-emitting diodes. Our results show that all tested UVC devices can effectively inactivate SARS-CoV-2, among which the KrCl* excimer had the best disinfection performance (i.e., highest inactivation rate). The inactivation rate constants of SARS-CoV-2 across wavelengths are similar to those for murine hepatitis virus (MHV) from our previous investigation, suggesting that MHV can serve as a reliable surrogate of SARS-CoV-2 with a lower BSL requirement (BSL2) during UV disinfection tests. This study provides fundamental information on UVC's action on SARS-CoV-2 and guidance for achieving reliable disinfection performance with UVC devices. IMPORTANCE UV light is an effective tool to help stem the spread of respiratory viruses and protect public health in commercial, public, transportation, and health care settings. For effective use of UV, there is a need to determine the efficiency of different UV wavelengths in killing pathogens, specifically SARS-CoV-2, to support efforts to control the ongoing COVID-19 global pandemic and future coronavirus-caused respiratory virus pandemics. We found that SARS-CoV-2 can be inactivated effectively using a broad range of UVC wavelengths, and 222 nm provided the best disinfection performance. Interestingly, 222-nm irradiation has been found to be safe for human exposure up to thresholds that are beyond those effective for inactivating viruses. Therefore, applying UV light from KrCl* excimers in public spaces can effectively help reduce viral aerosol or surface-based transmissions.


Subject(s)
Disinfection/methods , SARS-CoV-2/radiation effects , Virus Inactivation/radiation effects , Animals , Bacteriophage phi 6/radiation effects , COVID-19/prevention & control , COVID-19/transmission , Coronavirus 229E, Human/radiation effects , Disinfection/instrumentation , Humans , Mice , Murine hepatitis virus/radiation effects , Ultraviolet Rays
3.
J Infect Dev Ctries ; 15(9): 1252-1256, 2021 09 30.
Article in English | MEDLINE | ID: covidwho-1478143

ABSTRACT

INTRODUCTION: The COVID-19 pandemic highlights the role of environmental cleaning in controlling infection transmission in hospitals. However, cleaning practice remains inadequate. An important component of effective cleaning is to obtain feedback on actual cleaning practice. This study aimed to evaluate the cleaning process quality from an implementation perspective. METHODOLOGY: An observational study was conducted in a tertiary public hospital in Wuhan, China and 92 cleaning processes of units housing patients with multidrug-resistant organism infections were recorded. The bed unit cleaning quality and floor cleaning quality were measured by six and five process indicators respectively. Descriptive statistics were used to describe the cleaning quality. RESULTS: For bed unit cleaning quality, the appropriate rates of cleaning sequence, adherence to cleaning unit principle, use of cloth, use of cloth bucket, separation of clean and contaminated tools, and disinfectant concentration were 35.9%, 71.7%, 89.7%, 11.5%, 65.4%, and 48.7%, respectively. For floor cleaning quality, the appropriate rates of adherence to cleaning unit principle, use of cloth, use of cloth bucket, separation of clean and contaminated tools, and disinfectant concentration were 13.4%, 50.0%, 35.5%, 11.0%, and 36.7%, respectively. CONCLUSIONS: The cleaning staff showed poor environmental cleaning quality, especially the floor cleaning quality. The findings can help reveal deficiencies in cleaning practices, raise awareness of these deficiencies, and inform targeted strategies to improve cleaning quality and hospital safety.


Subject(s)
Disinfection/methods , Infection Control/methods , China , Cross Infection/prevention & control , Cross-Sectional Studies , Disinfection/standards , Drug Resistance, Multiple, Bacterial , Guideline Adherence/statistics & numerical data , Hospitals, Public , Hospitals, Teaching , Infection Control/standards , Tertiary Care Centers
4.
Microbiol Spectr ; 9(2): e0053721, 2021 10 31.
Article in English | MEDLINE | ID: covidwho-1476396

ABSTRACT

UV light, more specifically UV-C light at a wavelength of 254 nm, is often used to disinfect surfaces, air, and liquids. In early 2020, at the cusp of the COVID-19 pandemic, UV light was identified as an efficient means of eliminating coronaviruses; however, the variability in published sensitivity data is evidence of the need for experimental rigor to accurately quantify the effectiveness of this technique. In the current study, reliable and reproducible UV techniques have been adopted, including accurate measurement of light intensity, consideration of fluid UV absorbance, and confirmation of uniform dose delivery, including dose verification using an established biological target (T1UV bacteriophage) and a resistant recombinant virus (baculovirus). The experimental results establish the UV sensitivity of SARS-CoV-2, HCoV-229E, HCoV-OC43, and mouse hepatitis virus (MHV) and highlight the potential for surrogate viruses for disinfection studies. All four coronaviruses were found to be easily inactivated by 254 nm irradiation, with UV sensitivities of 1.7, 1.8, 1.7, and 1.2 mJ/cm2/log10 reduction for SARS-CoV-2, HCoV-229E, HCoV-OC43, and MHV, respectively. Similar UV sensitivities for these species demonstrate the capacity for HCoV-OC43, HCoV-229E, and MHV to be considered surrogates for SARS-CoV-2 in UV-inactivation studies, greatly reducing hazards and simplifying procedures for future experimental studies. IMPORTANCE Disinfection of SARS-CoV-2 is of particular importance due to the global COVID-19 pandemic. UV-C irradiation is a compelling disinfection technique because it can be applied to surfaces, air, and water and is commonly used in drinking water and wastewater treatment facilities. UV inactivation depends on the dose received by an organism, regardless of the intensity of the light source or the optical properties of the medium in which it is suspended. The 254 nm irradiation sensitivity was accurately determined using benchmark methodology and a collimated beam apparatus for four coronaviruses (SARS-CoV-2, HCoV-229E, HCoV-OC43, and MHV), a surrogate indicator organism (T1UV), and a resistant recombinant virus (baculovirus vector). Considering the light distribution across the sample surface, the attenuation of light intensity with fluid depth, the optical absorbance of the fluid, and the sample uniformity due to mixing enable accurate measurement of the fundamental inactivation kinetics and UV sensitivity.


Subject(s)
Coronavirus 229E, Human/radiation effects , Coronavirus OC43, Human/radiation effects , Murine hepatitis virus/radiation effects , SARS-CoV-2/radiation effects , Ultraviolet Rays , Animals , Baculoviridae/radiation effects , COVID-19/prevention & control , Cell Line , Chlorocebus aethiops , Disinfection/methods , Humans , Vero Cells
6.
PLoS One ; 16(10): e0258336, 2021.
Article in English | MEDLINE | ID: covidwho-1463315

ABSTRACT

Decontaminating N95 respirators for reuse could mitigate shortages during the COVID-19 pandemic. Although the United States Center for Disease Control has identified Ultraviolet-C irradiation as one of the most promising methods for N95 decontamination, very few studies have evaluated the efficacy of Ultraviolet-C for SARS-CoV-2 inactivation. In addition, most decontamination studies are performed using mask coupons that do not recapitulate the complexity of whole masks. We sought to directly evaluate the efficacy of Ultraviolet-C mediated inactivation of SARS-CoV-2 on N95 respirators. To that end we created a portable UV-C light-emitting diode disinfection chamber and tested decontamination of SARS-CoV-2 at different sites on two models of N95 respirator. We found that decontamination efficacy depends on mask model, material and location of the contamination on the mask. Our results emphasize the need for caution when interpreting efficacy data of UV-C decontamination methods.


Subject(s)
Decontamination , Disinfection , Masks , N95 Respirators , Ultraviolet Rays , Decontamination/instrumentation , Decontamination/methods , Disinfection/instrumentation , Disinfection/methods , Equipment Reuse
7.
Sci Rep ; 11(1): 19930, 2021 10 07.
Article in English | MEDLINE | ID: covidwho-1462026

ABSTRACT

Transmission of SARS-CoV-2 by aerosols has played a significant role in the rapid spread of COVID-19 across the globe. Indoor environments with inadequate ventilation pose a serious infection risk. Whilst vaccines suppress transmission, they are not 100% effective and the risk from variants and new viruses always remains. Consequently, many efforts have focused on ways to disinfect air. One such method involves use of minimally hazardous 222 nm far-UVC light. Whilst a small number of controlled experimental studies have been conducted, determining the efficacy of this approach is difficult because chamber or room geometry, and the air flow within them, influences both far-UVC illumination and aerosol dwell times. Fortunately, computational multiphysics modelling allows the inadequacy of dose-averaged assessment of viral inactivation to be overcome in these complex situations. This article presents the first validation of the WYVERN radiation-CFD code for far-UVC air-disinfection against survival fraction measurements, and the first measurement-informed modelling approach to estimating far-UVC susceptibility of viruses in air. As well as demonstrating the reliability of the code, at circa 70% higher, our findings indicate that aerosolized human coronaviruses are significantly more susceptible to far-UVC than previously thought.


Subject(s)
Coronavirus 229E, Human/radiation effects , Coronavirus Infections/prevention & control , Coronavirus OC43, Human/radiation effects , Disinfection/methods , Ultraviolet Rays , Virus Inactivation/radiation effects , Aerosols/isolation & purification , Air Microbiology , COVID-19/prevention & control , Computer Simulation , Coronavirus 229E, Human/isolation & purification , Coronavirus 229E, Human/physiology , Coronavirus OC43, Human/isolation & purification , Coronavirus OC43, Human/physiology , Disinfection/instrumentation , Equipment Design , Humans , Models, Biological
8.
Sci Rep ; 11(1): 19470, 2021 09 30.
Article in English | MEDLINE | ID: covidwho-1447318

ABSTRACT

The germicidal potential of specific wavelengths within the electromagnetic spectrum is an area of growing interest. While ultra-violet (UV) based technologies have shown satisfactory virucidal potential, the photo-toxicity in humans coupled with UV associated polymer degradation limit their use in occupied spaces. Alternatively, longer wavelengths with less irradiation energy such as visible light (405 nm) have largely been explored in the context of bactericidal and fungicidal applications. Such studies indicated that 405 nm mediated inactivation is caused by the absorbance of porphyrins within the organism creating reactive oxygen species which result in free radical damage to its DNA and disruption of cellular functions. The virucidal potential of visible-light based technologies has been largely unexplored and speculated to be ineffective given the lack of porphyrins in viruses. The current study demonstrated increased susceptibility of lipid-enveloped respiratory pathogens of importance such as SARS-CoV-2 (causative agent of COVID-19) and influenza A virus to 405 nm, visible light in the absence of exogenous photosensitizers thereby indicating a potential alternative porphyrin-independent mechanism of visible light mediated viral inactivation. These results were obtained using less than expected irradiance levels which are considered safe for humans and commercially achievable. Our results support further exploration of the use of visible light technology for the application of continuous decontamination in occupied areas within hospitals and/or infectious disease laboratories, specifically for the inactivation of respiratory pathogens such as SARS-CoV-2 and Influenza A.


Subject(s)
Disinfection/methods , Influenza A Virus, H1N1 Subtype/radiation effects , SARS-CoV-2/radiation effects , Disinfection/instrumentation , Dose-Response Relationship, Radiation , Encephalomyocarditis virus/radiation effects , Light , Time Factors , Virus Inactivation/radiation effects
9.
PLoS One ; 16(9): e0257434, 2021.
Article in English | MEDLINE | ID: covidwho-1443838

ABSTRACT

Although research has shown that the COVID-19 disease is most likely caused by airborne transmission of the SARS-CoV-2 virus, disinfection of potentially contaminated surfaces is also recommended to limit the spread of the disease. Use of electrostatic sprayers (ESS) and foggers to rapidly apply disinfectants over large areas or to complex surfaces has emerged with the COVID-19 pandemic. ESSs are designed to impart an electrostatic charge to the spray droplets with the goal of increasing deposition of the droplets onto surfaces, thereby promoting more efficient use of the disinfectant. The purpose of this research was to evaluate several spray parameters for different types of sprayers and foggers, as they relate to the application of disinfectants. Some of the parameters evaluated included the spray droplet size distribution, the electrostatic charge, the ability of the spray to wrap around objects, and the loss of disinfectant chemical active ingredient due to the spray process. The results show that most of the devices evaluated for droplet size distribution had an average volume median diameter ≥ 40 microns, and that four out of the six ESS tested for charge/mass produced sprays of at least 0.1 mC/kg. A minimal wrap-around effect of the spray deposition onto a cylindrical object was observed. The loss of disinfectant active ingredient to the air due to spraying was minimal for the two disinfectants tested, and concurrently, the active ingredient concentrations of the liquid disinfectants sprayed and collected 3 feet (1 meter) away from the spray nozzle do not decrease.


Subject(s)
COVID-19/prevention & control , Disinfectants/administration & dosage , Disinfection/instrumentation , Disinfectants/pharmacology , Disinfection/methods , Equipment Design , Humans , SARS-CoV-2/drug effects , Static Electricity , Surface Properties/drug effects
10.
Biocontrol Sci ; 26(3): 129-135, 2021.
Article in English | MEDLINE | ID: covidwho-1438813

ABSTRACT

The current pandemic of novel coronavirus disease (COVID-19) has highlighted the importance of disinfectants. As a raw material for next-generation disinfectants, scallop shell-derived calcium oxide (CaO) has been revealed to exhibit significant virucidal and microbicidal activities and is compatible with living tissues and the environment. This minireview summarizes recent progress in the development of disinfectants from scallop shell-CaO, focusing especially on studies of clinical and daily use applications. We describe the preparation, basic characteristics, and virucidal and microbicidal activities of scallop shell-CaO disinfectants. Furthermore, their applications in the disinfection of contaminated masks and the treatment of infected wounds are briefly introduced.


Subject(s)
Animal Shells/chemistry , Calcium Compounds/pharmacology , Disinfectants/pharmacology , Disinfection/methods , Oxides/pharmacology , Pectinidae/chemistry , Animals , Disinfection/instrumentation , Disinfection/trends , Humans
11.
Br J Radiol ; 94(1127): 20210607, 2021 Nov 01.
Article in English | MEDLINE | ID: covidwho-1430509

ABSTRACT

OBJECTIVES: The COVID-19 pandemic has highlighted the importance of aerosol spread of infection. We have conducted a study to detect bacterial contamination of room surfaces and room air during CT colonography and confirm the efficacy of room disinfection procedures carried out between examinations. METHODS: Systematic sampling of the CT examination couch and horizontal surfaces 1 m and 3 m from the couch was performed before and after patient examinations. A 1 m3 sample of room air was obtained during patient examinations. Samples were processed using routine laboratory methods. A case-control study design was used (30 CT colonography and 30 routine body CT scans). RESULTS: Evidence of airborne dissemination of bacteria was detected in >30% of CT colonography examinations and <10% of control examinations (p = 0.01). No pathogenic bacteria were detected in surface samples taken before patient examinations. CONCLUSION: The room disinfection policy in use in our CT department is effective in eliminating pathogenic bacteria from surfaces in the patient environment. CT colonography causes contamination of room air with enteric bacteria in a significant proportion of cases. ADVANCES IN KNOWLEDGE: CT colonography may possibly be an aerosol-generating procedure. Larger-scale investigation is needed to fully evaluate this potential infection risk.


Subject(s)
Air Pollutants/isolation & purification , Colonography, Computed Tomographic/methods , Disinfection/methods , Enterobacteriaceae/isolation & purification , Equipment Contamination/statistics & numerical data , Feces/microbiology , Aerosols , Case-Control Studies , Humans , United Kingdom
12.
Sci Rep ; 11(1): 18213, 2021 09 14.
Article in English | MEDLINE | ID: covidwho-1410885

ABSTRACT

With the spread of COVID-19, significant emphasis has been placed on mitigation techniques such as mask wearing to slow infectious disease transmission. Widespread use of face coverings has revealed challenges such as mask contamination and waste, presenting an opportunity to improve the current technologies. In response, we have developed the Auto-sanitizing Retractable Mask Optimized for Reusability (ARMOR). ARMOR is a novel, reusable face covering that can be quickly disinfected using an array of ultraviolet C lamps contained within a wearable case. A nanomembrane UVC sensor was used to quantify the intensity of germicidal radiation at 18 different locations on the face covering and determine the necessary exposure time to inactivate SARS-CoV-2 in addition to other viruses and bacteria. After experimentation, it was found that ARMOR successfully provided germicidal radiation to all areas of the mask and will inactivate SARS-CoV-2 in approximately 180 s, H1N1 Influenza in 130 s, and Mycobacterium tuberculosis in 113 s, proving that this design is effective at eliminating a variety of pathogens and can serve as an alternative to traditional waste-producing disposable face masks. The accessibility, ease of use, and speed of sanitization supports the wide application of ARMOR in both clinical and public settings.


Subject(s)
Disinfection/methods , Masks , COVID-19/prevention & control , COVID-19/virology , Disinfection/instrumentation , Humans , Influenza A Virus, H1N1 Subtype/radiation effects , Mycobacterium tuberculosis/radiation effects , SARS-CoV-2/isolation & purification , SARS-CoV-2/radiation effects , Ultraviolet Rays
13.
Molecules ; 26(18)2021 Sep 08.
Article in English | MEDLINE | ID: covidwho-1410351

ABSTRACT

This study aimed to compare the SARS-CoV-2-inactivation activity and virucidal mechanisms of ozonated water (OW) with those of slightly acidic electrolyzed water (SAEW) and 70% ethanol (EtOH). SARS-CoV-2-inactivation activity was evaluated in a virus solution containing 1%, 20% or 40% fetal bovine serum (FBS) with OW, SAEW or EtOH at a virus-to-test solution ratio of 1:9, 1:19 or 1:99 for a reaction time of 20 s. EtOH showed the strongest virucidal activity, followed by SAEW and OW. Even though EtOH potently inactivated the virus despite the 40% FBS concentration, virus inactivation by OW and SAEW decreased in proportion to the increase in FBS concentration. Nevertheless, OW and SAEW showed potent virucidal activity with 40% FBS at a virus-to-test solution ratio of 1:99. Real-time PCR targeting the viral genome revealed that cycle threshold values in the OW and SAEW groups were significantly higher than those in the control group, suggesting that OW and SAEW disrupted the viral genome. Western blotting analysis targeting the recombinant viral spike protein S1 subunit showed a change in the specific band into a ladder upon treatment with OW and SAEW. OW and SAEW may cause conformational changes in the S1 subunit of the SARS-CoV-2 spike protein.


Subject(s)
COVID-19/prevention & control , Disinfectants/pharmacology , Disinfection/methods , Ethanol/pharmacology , Ozone/pharmacology , SARS-CoV-2/drug effects , Humans
15.
Photochem Photobiol Sci ; 20(7): 955-965, 2021 Jul.
Article in English | MEDLINE | ID: covidwho-1384775

ABSTRACT

The pandemic created by SARS-CoV-2 has caused a shortage in the supplies of N95 filtering facepiece respirators (FFRs), disposable respirators with at least 95% efficiency to remove non-oily airborne particles, due to increasing cases all over the world. The current article reviewed various possible decontamination methods for FFR reuse including ultraviolet germicidal irradiation (UVGI), hydrogen peroxide vapor (HPV), microwave-generated steam (MGS), hydrogen peroxide gas plasma (HPGP), and 70% or higher ethanol solution. HPV decontamination was effective against bacterial spores (6 log10 reduction of Geobacillus stearothermophilus spores) on FFRs and viruses (> 4 log10 reduction of various types of viruses) on inanimate surfaces, and no degradation of respirator materials and fit has been reported. 70% or higher ethanol decontamination showed high efficacy in inactivation of coronaviruses on inanimate surfaces (> 3.9 log10 reduction) but it was lower on FFRs which filtration efficiency was also decreased. UVGI method had good biocidal efficacy on FFRs (> 3 log10 reduction of H1N1 virus) combined with inexpensive, readily available equipment; however, it was more time-consuming to ensure sufficient reduction in SARS-CoV-2. MGS treatment also provided good viral decontamination on FFRs (> 4 log10 reduction of H1N1 virus) along with less time-intensive process and readily available equipment while inconsistent disinfection on the treated surfaces and deterioration of nose cushion of FFRs were observed. HPGP was a good virucidal system (> 6 log10 reduction of Vesicular stomatitis virus) but filtration efficiency after decontamination was inconsistent. Overall, HPV appeared to be one of the most promising methods based on the high biocidal efficacy on FFRs, preservation of respirator performance after multiple cycles, and no residual chemical toxicity. Nonetheless, equipment cost and time of the HPV process and a suitable operating room need to be considered.


Subject(s)
COVID-19 , Decontamination/methods , N95 Respirators/microbiology , N95 Respirators/virology , Bacteria/drug effects , Bacteria/isolation & purification , Bacteria/radiation effects , COVID-19/epidemiology , Disinfection/methods , Ethanol/pharmacology , Humans , Hydrogen Peroxide/pharmacology , Microwaves , Ultraviolet Rays , Viruses/drug effects , Viruses/isolation & purification , Viruses/radiation effects
16.
PLoS One ; 16(5): e0251817, 2021.
Article in English | MEDLINE | ID: covidwho-1388915

ABSTRACT

The transmission of SARS-CoV-2 through contact with contaminated surfaces or objects is an important form of transmissibility. Thus, in this study, we evaluated the performance of a disinfection chamber designed for instantaneous dispersion of the biocidal agent solution, in order to characterize a new device that can be used to protect individuals by reducing the transmissibility of the disease through contaminated surfaces. We proposed the necessary adjustments in the configuration to improve the dispersion on surfaces and the effectiveness of the developed equipment. Computational Fluid Dynamics (CFD) simulations of the present technology with a chamber having six nebulizer nozzles were performed and validated through qualitative and quantitative comparisons, and experimental tests were conducted using the method Water-Sensitive Paper (WSP), with an exposure to the biocidal agent for 10 and 30 s. After evaluation, a new passage procedure for the chamber with six nozzles and a new configuration of the disinfection chamber were proposed. In the chamber with six nozzles, a deficiency was identified in its central region, where the suspended droplet concentration was close to zero. However, with the new passage procedure, there was a significant increase in wettability of the surface. With the proposition of the chamber with 12 nozzles, the suspended droplet concentration in different regions increased, with an average increase of 266%. The experimental results of the new configuration proved that there was an increase in wettability at all times of exposure, and it was more significant for an exposure of 30 s. Additionally, even in different passage procedures, there were no significant differences in the results for an exposure of 10 s, thereby showing the effectiveness of the new configuration or improved spraying and wettability by the biocidal agent, as well as in minimizing the impact caused by human factor in the performance of the disinfection technology.


Subject(s)
COVID-19/epidemiology , Decontamination/methods , Disinfection/methods , SARS-CoV-2/drug effects , COVID-19/metabolism , COVID-19/transmission , COVID-19/virology , Decontamination/instrumentation , Disinfectants/analysis , Disinfection/instrumentation , Humans , Hydrodynamics , Models, Theoretical , Pandemics , SARS-CoV-2/isolation & purification
17.
Photochem Photobiol ; 97(3): 532-541, 2021 05.
Article in English | MEDLINE | ID: covidwho-1388390

ABSTRACT

During the current SARS-CoV-2 and tuberculosis global pandemics, public health and infection prevention and control professionals wrestle with cost-effective means to control airborne transmission. One technology recommended by Centers for Disease Control and Prevention and the World Health Organization for lowering indoor concentration of these and other microorganisms and viruses is upper-room ultraviolet 254 nm (UVC254 ) systems. Applying both a material balance as well as some nondimensional parameters developed by Rudnick and First, the impact of several critical parameters and their effect on the fraction of microorganisms surviving UVC254 exposure was evaluated. Vertical airspeed showed a large impact at velocities <0.05 m s-1 but a lesser effect at velocities >0.05 m s-1 . In addition, the efficacy of any upper-room UVC system is influenced greatly by the mean room fluence rate as opposed to a simple volume- or area-based dosing criteria. An alternative UVC254 dosing strategy was developed based on the fluence rate as a function of the UVC254 luminaire output (W) and the square root of the product of the room volume and the ceiling height.


Subject(s)
Air Microbiology , Disinfection/instrumentation , Disinfection/methods , Lighting , Ultraviolet Rays , Air Pollution, Indoor/prevention & control , Animals , COVID-19/prevention & control , Environment, Controlled , Infection Control/methods , SARS-CoV-2/radiation effects , Virus Inactivation/radiation effects
18.
Photochem Photobiol ; 97(3): 549-551, 2021 05.
Article in English | MEDLINE | ID: covidwho-1388389

ABSTRACT

Although the environmental control measure of ultraviolet germicidal irradiation (UVGI) for disinfection has not been widely used in the United States and some parts of the world in the past few decades, this technology has been well applied in Russia. UVGI technology has been particularly useful with regard to limiting TB transmission in medical facilities. There is good evidence that UV-C (180-280 nm) air disinfection can be a helpful intervention in reducing transmission of the SARS-CoV-2 virus.


Subject(s)
COVID-19/prevention & control , Disinfection/methods , Hospitals/standards , SARS-CoV-2/radiation effects , Ultraviolet Rays , Virus Inactivation/radiation effects , Air Microbiology , Air Pollution, Indoor/prevention & control , COVID-19/epidemiology , Disinfection/instrumentation , Humans , Infection Control , Russia
19.
Photochem Photobiol ; 97(3): 542-548, 2021 05.
Article in English | MEDLINE | ID: covidwho-1388388

ABSTRACT

Potential for SARS-CoV-2 viral inactivation by solar UV radiation in outdoor spaces in the UK has been assessed. Average erythema effective and UV-A daily radiant exposures per month were higher (statistically significant, P < 0.05) in spring 2020 in comparison with spring 2015-2019 across most of the UK, while irradiance generally appeared to be in the normal expected range of 2015-2019. It was found that these higher radiant exposures may have increased the potential for SARS-CoV-2 viral inactivation outdoors in April and May 2020. Assessment of the 6-year period 2015-2020 in the UK found that for 50-60% of the year, that is most of October to March, solar UV is unlikely to have a significant (at least 90% inactivation) impact on viral inactivation outdoors. Minimum times to reach 90% and 99% inactivation in the UK are of the order of tens of minutes and of the order of hours, respectively. However, these times are best case scenarios and should be treated with caution.


Subject(s)
COVID-19/prevention & control , SARS-CoV-2/radiation effects , Ultraviolet Rays , Virus Inactivation/radiation effects , COVID-19/virology , Disinfection/instrumentation , Disinfection/methods , Humans , Radiation Exposure , Sunlight , United Kingdom
20.
Sci Rep ; 11(1): 12999, 2021 06 21.
Article in English | MEDLINE | ID: covidwho-1387481

ABSTRACT

An ever-increasing number of medical staff use mobile phones as a work aid, yet this may pose nosocomial diseases. To assess and report via a survey the handling practices and the use of phones by paediatric wards healthcare workers. 165 paediatric healthcare workers and staff filled in a questionnaire consisting of 14 questions (including categorical, ordinal and numerical data). Analysis of categorical data used non-parametric techniques such as the Chi-squared test. Although 98% of respondents (165 in total) report that their phones may be contaminated, 56% have never cleaned their devices. Of the respondents that clean their devices, 10% (17/165) had done so with alcohol swabs or disinfectant within that day or week; and an additional 12% respondents (20/165) within that month. Of concern, 52% (86/165) of the respondents use their phones in the bathroom, emphasising the unhygienic environments in which mobile phones/smartphones are constantly used. Disinfecting phones is a practice that only a minority of healthcare workers undertake appropriately. Mobile phones, present in billions globally, are therefore Trojan Horses if contaminated with microbes and potentially contributing to the spread and propagation of micro-organisms as per the rapid spread of SARS-CoV-2 virus in the world.


Subject(s)
Bathroom Equipment/virology , COVID-19/prevention & control , Cell Phone/instrumentation , Cross Infection/prevention & control , Delivery of Health Care/methods , Disinfection/methods , Hospitals, Pediatric , Personnel, Hospital , SARS-CoV-2 , COVID-19/virology , Cross Infection/virology , Emergency Service, Hospital , Female , Hand Hygiene , Humans , Intensive Care Units, Neonatal , Male , Risk Factors , Self Report
SELECTION OF CITATIONS
SEARCH DETAIL
...