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1.
Indoor Air ; 32(2): e12976, 2022 02.
Article in English | MEDLINE | ID: covidwho-1669148

ABSTRACT

We propose the Transmission of Virus in Carriages (TVC) model, a computational model which simulates the potential exposure to SARS-CoV-2 for passengers traveling in a subway rail system train. This model considers exposure through three different routes: fomites via contact with contaminated surfaces; close-range exposure, which accounts for aerosol and droplet transmission within 2 m of the infectious source; and airborne exposure via small aerosols which does not rely on being within 2 m distance from the infectious source. Simulations are based on typical subway parameters and the aim of the study is to consider the relative effect of environmental and behavioral factors including prevalence of the virus in the population, number of people traveling, ventilation rate, and mask wearing as well as the effect of model assumptions such as emission rates. Results simulate generally low exposures in most of the scenarios considered, especially under low virus prevalence. Social distancing through reduced loading and high mask-wearing adherence is predicted to have a noticeable effect on reducing exposure through all routes. The highest predicted doses happen through close-range exposure, while the fomite route cannot be neglected; exposure through both routes relies on infrequent events involving relatively few individuals. Simulated exposure through the airborne route is more homogeneous across passengers, but is generally lower due to the typically short duration of the trips, mask wearing, and the high ventilation rate within the carriage. The infection risk resulting from exposure is challenging to estimate as it will be influenced by factors such as virus variant and vaccination rates.


Subject(s)
Air Pollution, Indoor , COVID-19 , Railroads , Aerosols , Air Microbiology , COVID-19/transmission , Fomites/virology , Humans , SARS-CoV-2
2.
PLoS One ; 17(1): e0261365, 2022.
Article in English | MEDLINE | ID: covidwho-1643242

ABSTRACT

BACKGROUND: Cleanliness of hospital surfaces helps prevent healthcare-associated infections, but comparative evaluations of various cleaning strategies during COVID-19 pandemic surges and worker shortages are scarce. PURPOSE AND METHODS: To evaluate the effectiveness of daily, enhanced terminal, and contingency-based cleaning strategies in an acute care hospital (ACH) and a long-term care facility (LTCF), using SARS-CoV-2 RT-PCR and adenosine triphosphate (ATP) assays. Daily cleaning involved light dusting and removal of visible debris while a patient is in the room. Enhanced terminal cleaning involved wet moping and surface wiping with disinfectants after a patient is permanently moved out of a room followed by ultraviolet light (UV-C), electrostatic spraying, or room fogging. Contingency-based strategies, performed only at the LTCF, involved cleaning by a commercial environmental remediation company with proprietary chemicals and room fogging. Ambient surface contamination was also assessed randomly, without regard to cleaning times. Near-patient or high-touch stationary and non-stationary environmental surfaces were sampled with pre-moistened swabs in viral transport media. RESULTS: At the ACH, SARS-CoV-2 RNA was detected on 66% of surfaces before cleaning and on 23% of those surfaces immediately after terminal cleaning, for a 65% post-cleaning reduction (p = 0.001). UV-C enhancement resulted in an 83% reduction (p = 0.023), while enhancement with electrostatic bleach application resulted in a 50% reduction (p = 0.010). ATP levels on RNA positive surfaces were not significantly different from those of RNA negative surfaces. LTCF contamination rates differed between the dementia, rehabilitation, and residential units (p = 0.005). 67% of surfaces had RNA after room fogging without terminal-style wiping. Fogging with wiping led to a -11% change in the proportion of positive surfaces. At the LTCF, mean ATP levels were lower after terminal cleaning (p = 0.016). CONCLUSION: Ambient surface contamination varied by type of unit and outbreak conditions, but not facility type. Removal of SARS-CoV-2 RNA varied according to cleaning strategy. IMPLICATIONS: Previous reports have shown time spent cleaning by hospital employed environmental services staff did not correlate with cleaning thoroughness. However, time spent cleaning by a commercial remediation company in this study was associated with cleaning effectiveness. These findings may be useful for optimizing allocation of cleaning resources during staffing shortages.


Subject(s)
COVID-19/prevention & control , Cross Infection/prevention & control , Disinfection/methods , Health Personnel/organization & administration , Infection Control/organization & administration , Long-Term Care/organization & administration , Adenosine Triphosphate/analysis , COVID-19/epidemiology , Cross Infection/epidemiology , Disinfectants , Fomites/virology , Health Facilities , Humans , New York/epidemiology , Patients' Rooms , RNA, Viral/analysis , SARS-CoV-2/genetics , SARS-CoV-2/pathogenicity , SARS-CoV-2/radiation effects , Ultraviolet Rays
3.
J Hazard Mater ; 425: 128051, 2022 03 05.
Article in English | MEDLINE | ID: covidwho-1561920

ABSTRACT

The number of people infected with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) continues to increase worldwide, but despite extensive research, there remains significant uncertainty about the predominant routes of SARS-CoV-2 transmission. We conducted a mechanistic modeling and calculated the exposure dose and infection risk of each passenger in a two-bus COVID-19 outbreak in Hunan province, China. This outbreak originated from a single pre-symptomatic index case. Some human behavioral data related to exposure including boarding and alighting time of some passengers and seating position and mask wearing of all passengers were obtained from the available closed-circuit television images/clips and/or questionnaire survey. Least-squares fitting was performed to explore the effect of effective viral load on transmission risk, and the most likely quanta generation rate was also estimated. This study reveals the leading role of airborne SARS-CoV-2 transmission and negligible role of fomite transmission in a poorly ventilated indoor environment, highlighting the need for more targeted interventions in such environments. The quanta generation rate of the index case differed by a factor of 1.8 on the two buses and transmission occurred in the afternoon of the same day, indicating a time-varying effective viral load within a short period of five hours.


Subject(s)
Air Microbiology , COVID-19 , Fomites/virology , Motor Vehicles , SARS-CoV-2 , COVID-19/transmission , Disease Outbreaks , Humans
4.
Indoor Air ; 32(1): e12968, 2022 Jan.
Article in English | MEDLINE | ID: covidwho-1550827

ABSTRACT

Despite their considerable prevalence, dynamics of hospital-associated COVID-19 are still not well understood. We assessed the nature and extent of air- and surface-borne SARS-CoV-2 contamination in hospitals to identify hazards of viral dispersal and enable more precise targeting of infection prevention and control. PubMed, ScienceDirect, Web of Science, Medrxiv, and Biorxiv were searched for relevant articles until June 1, 2021. In total, 51 observational cross-sectional studies comprising 6258 samples were included. SARS-CoV-2 RNA was detected in one in six air and surface samples throughout the hospital and up to 7.62 m away from the nearest patients. The highest detection rates and viral concentrations were reported from patient areas. The most frequently and heavily contaminated types of surfaces comprised air outlets and hospital floors. Viable virus was recovered from the air and fomites. Among size-fractionated air samples, only fine aerosols contained viable virus. Aerosol-generating procedures significantly increased (ORair  = 2.56 (1.46-4.51); ORsurface  = 1.95 (1.27-2.99)), whereas patient masking significantly decreased air- and surface-borne SARS-CoV-2 contamination (ORair  = 0.41 (0.25-0.70); ORsurface  = 0.45 (0.34-0.61)). The nature and extent of hospital contamination indicate that SARS-CoV-2 is likely dispersed conjointly through several transmission routes, including short- and long-range aerosol, droplet, and fomite transmission.


Subject(s)
Air Pollution, Indoor , COVID-19 , Cross Infection/transmission , Hospitals , Air Microbiology , COVID-19/transmission , Cross-Sectional Studies , Fomites/virology , Humans , Observational Studies as Topic , SARS-CoV-2
6.
Appl Environ Microbiol ; 87(22): e0121521, 2021 10 28.
Article in English | MEDLINE | ID: covidwho-1494942

ABSTRACT

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.


Subject(s)
Fingers/virology , Fomites/virology , Virus Physiological Phenomena , Bacteriophage phi 6/physiology , Bacteriophage phi 6/ultrastructure , Fomites/classification , Hand Hygiene , Humans , Levivirus/physiology , Levivirus/ultrastructure , Viral Envelope/ultrastructure , Virus Diseases/transmission , Virus Diseases/virology , Viruses/ultrastructure
7.
Indoor Air ; 32(1): e12938, 2022 Jan.
Article in English | MEDLINE | ID: covidwho-1480133

ABSTRACT

Self-contamination during doffing of personal protective equipment (PPE) is a concern for healthcare workers (HCW) following SARS-CoV-2-positive patient care. Staff may subconsciously become contaminated through improper glove removal; so, quantifying this exposure is critical for safe working procedures. HCW surface contact sequences on a respiratory ward were modeled using a discrete-time Markov chain for: IV-drip care, blood pressure monitoring, and doctors' rounds. Accretion of viral RNA on gloves during care was modeled using a stochastic recurrence relation. In the simulation, the HCW then doffed PPE and contaminated themselves in a fraction of cases based on increasing caseload. A parametric study was conducted to analyze the effect of: (1a) increasing patient numbers on the ward, (1b) the proportion of COVID-19 cases, (2) the length of a shift, and (3) the probability of touching contaminated PPE. The driving factors for the exposure were surface contamination and the number of surface contacts. The results simulate generally low viral exposures in most of the scenarios considered including on 100% COVID-19 positive wards, although this is where the highest self-inoculated dose is likely to occur with median 0.0305 viruses (95% CI =0-0.6 viruses). Dose correlates highly with surface contamination showing that this can be a determining factor for the exposure. The infection risk resulting from the exposure is challenging to estimate, as it will be influenced by the factors such as virus variant and vaccination rates.


Subject(s)
Air Pollution, Indoor , COVID-19 , Fomites , Occupational Exposure , Personal Protective Equipment , Fomites/virology , Gloves, Protective/virology , Hospitals , Humans , Personal Protective Equipment/virology , SARS-CoV-2
8.
Appl Environ Microbiol ; 87(21): e0137121, 2021 10 14.
Article in English | MEDLINE | ID: covidwho-1470497

ABSTRACT

Phage Phi6 is an enveloped virus considered a possible nonpathogenic surrogate for severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other viral pathogens in transmission studies. Larger input amounts of bacteriophage Phi6 are shown to delay and protect the phage from environmental decay, both when the phages are dried in plastic tubes and when they are stored in saline solution at 4°C. In contrast, when bacteriophage Phi6 is placed in LB (Luria-Bertani) growth medium (instead of saline) prior to placement on the plastic surface, the influence of the starting concentration on viral recovery is negligible. Protection is reflected in the phage half-lives at higher concentrations being longer than the half-lives at lower concentrations. Because experiments supporting the possibility of fomite transmission of SARS-CoV-2 and other viruses rely upon the survival of infectious virus following inoculation onto various surfaces, large initial amounts of input virus on a surface may generate artificially inflated survival times compared to realistic lower levels of virus that a subject would normally encounter. This is not only because there are extra half-lives to go through at higher concentrations but also because the half-lives themselves are extended at higher virus concentrations. It is important to design surface drying experiments for pathogens with realistic levels of input virus and to consider the role of the carrier and matrix if the results are to be clinically relevant. IMPORTANCE During the coronavirus disease 2019 (COVID-19) pandemic, much attention has been paid to the environmental decay of SARS-CoV-2 due to the proposed transmission of the virus via fomites. However, published experiments have commenced with inocula with very high virus titers, an experimental design not representative of real-life conditions. The study described here evaluated the impact of the initial virus titer on the environmental decay of an enveloped virus, using a nonpathogenic surrogate for the transmission of SARS-CoV-2, enveloped bacteriophage Phi6. We establish that higher concentrations of virus can protect the virus from environmental decay, depending on conditions. This has important implications for stability studies of SARS-CoV-2 and other viruses. Our results point to a limitation in the fundamental methodology that has been used to attribute fomite transmission for almost all respiratory viruses.


Subject(s)
Bacteriophage phi 6 , Pseudomonas syringae/virology , Culture Media , Desiccation , Fomites/virology , Half-Life , Plastics , SARS-CoV-2 , Saline Solution , Temperature , Virus Inactivation
9.
Trop Biomed ; 38(3): 462-468, 2021 Sep 01.
Article in English | MEDLINE | ID: covidwho-1451067

ABSTRACT

COVID-19 has spread rapidly worldwide. The role of fomites in facilitating onward transmission is plausible. This study aimed to determine the presence of viable virus and its persistence on the surfaces of fomites in wards treating COVID-19 patients in Malaysia. This study was conducted in two stages. First, environmental sampling was performed on random days in the intensive care unit (ICU) and general wards. Then, in the second stage, samples were collected serially on alternate days for 7 days in two selected general wards. In Stage 1, a total of 104 samples were collected from the surfaces of highly touched and used areas by patients and healthcare workers. Only three samples were tested positive for SARS-COV-2. In Stage 2, three surface samples were detected positive, but no persistence of the virus was observed. However, none of the SARS-CoV-2 RNA was viable through tissue culture. Overall, the environmental contamination of SARS-CoV-2 was low in this hospital setting. Hospitals' strict infection control and the compliance of patients with wearing masks may have played a role in these findings, suggesting adherence to those measures to reduce occupational exposure of COVID-19 in hospital settings.


Subject(s)
COVID-19/transmission , Environmental Exposure/statistics & numerical data , Fomites/virology , Infection Control/methods , Equipment Contamination , Hospitals/statistics & numerical data , Humans , Intensive Care Units/statistics & numerical data , Malaysia , Patients' Rooms/statistics & numerical data , SARS-CoV-2/isolation & purification
10.
Cancer Radiother ; 25(6-7): 645-647, 2021 Oct.
Article in French | MEDLINE | ID: covidwho-1439911

ABSTRACT

Paper patient file sharing has clearly been identified as a risk behavior for the COVID-19 virus transmission in radiotherapy units. In order to overcome this, the ONCORAD radiotherapy units worked on total dematerialization of the paper patient file, within 3 weeks. The methodology is based on a quality approch. This work has led to a convincing improvement in the management of risks a priori and a smoother patient care workflow.


Subject(s)
COVID-19/prevention & control , Electronic Health Records , Fomites/virology , Health Records, Personal , Paper , Radiation Oncology , COVID-19/transmission , Humans
11.
BMC Nephrol ; 22(1): 313, 2021 09 16.
Article in English | MEDLINE | ID: covidwho-1413890

ABSTRACT

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.


Subject(s)
Ambulatory Care Facilities , COVID-19/transmission , Fomites/virology , Interior Design and Furnishings , Outpatients , Renal Dialysis , Virus Shedding , Aged , COVID-19/epidemiology , Case-Control Studies , Environmental Exposure , Female , Humans , Infection Control/methods , Logistic Models , Male , Middle Aged , Models, Theoretical , Retrospective Studies , Risk , SARS-CoV-2 , United States/epidemiology
12.
Appl Environ Microbiol ; 87(14): e0052621, 2021 06 25.
Article in English | MEDLINE | ID: covidwho-1408384

ABSTRACT

The transmission of SARS-CoV-2 is likely to occur through a number of routes, including contact with contaminated surfaces. Many studies have used reverse transcription-PCR (RT-PCR) analysis to detect SARS-CoV-2 RNA on surfaces, but seldom has viable virus been detected. This paper investigates the viability over time of SARS-CoV-2 dried onto a range of materials and compares viability of the virus to RNA copies recovered and whether virus viability is concentration dependent. Viable virus persisted for the longest time on surgical mask material and stainless steel, with a 99.9% reduction in viability by 122 and 114 h, respectively. Viability of SARS-CoV-2 reduced the fastest on a polyester shirt, with a 99.9% reduction within 2.5 h. Viability on the bank note was reduced second fastest, with 99.9% reduction in 75 h. RNA on all surfaces exhibited a 1-log reduction in genome copy number recovery over 21 days. The findings show that SARS-CoV-2 is most stable on nonporous hydrophobic surfaces. RNA is highly stable when dried on surfaces, with only 1-log reduction in recovery over 3 weeks. In comparison, SARS-CoV-2 viability reduced more rapidly, but this loss in viability was found to be independent of starting concentration. Expected levels of SARS-CoV-2 viable environmental surface contamination would lead to undetectable levels within 2 days. Therefore, when RNA is detected on surfaces, it does not directly indicate the presence of viable virus, even at low cycle threshold values. IMPORTANCE This study shows the impact of material type on the viability of SARS-CoV-2 on surfaces. It demonstrates that the decay rate of viable SARS-CoV-2 is independent of starting concentration. However, RNA shows high stability on surfaces over extended periods. This has implications for interpretation of surface sampling results using RT-PCR to determine the possibility of viable virus from a surface, where RT-PCR is not an appropriate technique to determine viable virus. Unless sampled immediately after contamination, it is difficult to align RNA copy numbers to quantity of viable virus on a surface.


Subject(s)
COVID-19 , Fomites/virology , Personal Protective Equipment/virology , RNA, Viral/isolation & purification , SARS-CoV-2/isolation & purification , COVID-19/epidemiology , COVID-19/transmission , COVID-19/virology , Humans , Microbial Viability , Surface Properties
14.
Nature ; 583(7818): 834-838, 2020 07.
Article in English | MEDLINE | ID: covidwho-1387423

ABSTRACT

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), a novel coronavirus with high nucleotide identity to SARS-CoV and to SARS-related coronaviruses that have been detected in horseshoe bats, has spread across the world and had a global effect on healthcare systems and economies1,2. A suitable small animal model is needed to support the development of vaccines and therapies. Here we report the pathogenesis and transmissibility of SARS-CoV-2 in golden (Syrian) hamsters (Mesocricetus auratus). Immunohistochemistry assay demonstrated the presence of viral antigens in nasal mucosa, bronchial epithelial cells and areas of lung consolidation on days 2 and 5 after inoculation with SARS-CoV-2, followed by rapid viral clearance and pneumocyte hyperplasia at 7 days after inoculation. We also found viral antigens in epithelial cells of the duodenum, and detected viral RNA in faeces. Notably, SARS-CoV-2 was transmitted efficiently from inoculated hamsters to naive hamsters by direct contact and via aerosols. Transmission via fomites in soiled cages was not as efficient. Although viral RNA was continuously detected in the nasal washes of inoculated hamsters for 14 days, the communicable period was short and correlated with the detection of infectious virus but not viral RNA. Inoculated and naturally infected hamsters showed apparent weight loss on days 6-7 post-inoculation or post-contact; all hamsters returned to their original weight within 14 days and developed neutralizing antibodies. Our results suggest that features associated with SARS-CoV-2 infection in golden hamsters resemble those found in humans with mild SARS-CoV-2 infections.


Subject(s)
Betacoronavirus/pathogenicity , Coronavirus Infections/transmission , Coronavirus Infections/virology , Disease Models, Animal , Lung/pathology , Lung/virology , Mesocricetus/virology , Pneumonia, Viral/transmission , Pneumonia, Viral/virology , Aerosols , Alveolar Epithelial Cells/pathology , Alveolar Epithelial Cells/virology , Animals , Antibodies, Neutralizing/immunology , Antibodies, Viral/immunology , Antigens, Viral/immunology , Antigens, Viral/isolation & purification , Antigens, Viral/metabolism , Betacoronavirus/immunology , Betacoronavirus/isolation & purification , Betacoronavirus/metabolism , Bronchi/pathology , Bronchi/virology , COVID-19 , Coronavirus Infections/immunology , Duodenum/virology , Fomites/virology , Housing, Animal , Kidney/virology , Male , Mesocricetus/immunology , Nasal Mucosa/virology , Pandemics , Pneumonia, Viral/immunology , RNA, Viral/analysis , SARS-CoV-2 , Viral Load , Weight Loss
16.
FEMS Microbiol Lett ; 368(16)2021 09 01.
Article in English | MEDLINE | ID: covidwho-1377968

ABSTRACT

Limited research exists on the potential for leather to act as a fomite of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or endemic coronaviruses including human coronavirus (HCoV) OC43; this is important for settings such as the shoe manufacturing industry. Antiviral coating of leather hides could limit such risks. This study aimed to investigate the stability and transfer of HCoVOC43 on different leathers, as a surrogate for SARS-CoV-2, and assess the antiviral efficacy of a silver-based leather coating. The stability of HCoV-OC43 (6.6 log10) on patent, full-grain calf, corrected grain finished and nubuck leathers (silver additive-coated and uncoated) was measured by titration on BHK-21 cells. Transfer from leather to cardboard and stainless steel was determined. HCoV-OC43 was detectable for 6 h on patent, 24 h on finished leather and 48 h on calf leather; no infectious virus was recovered from nubuck. HCoV-OC43 transferred from patent, finished and calf leathers onto cardboard and stainless steel up to 2 h post-inoculation (≤3.1-5.5 log10), suggesting that leathers could act as fomites. Silver additive-coated calf and finished leathers were antiviral against HCoV-OC43, with no infectious virus recovered after 2 h and limited transfer to other surfaces. The silver additive could reduce potential indirect transmission of HCoV-OC43 from leather.


Subject(s)
Coronavirus Infections/transmission , Coronavirus OC43, Human/isolation & purification , Fomites/virology , Animals , Antiviral Agents/pharmacology , COVID-19/transmission , Cell Line , Coronavirus OC43, Human/drug effects , Cricetinae , Disease Transmission, Infectious/prevention & control , Fomites/classification , Humans , SARS-CoV-2/drug effects , SARS-CoV-2/isolation & purification , Silver/pharmacology
17.
J Med Virol ; 93(9): 5339-5349, 2021 09.
Article in English | MEDLINE | ID: covidwho-1363673

ABSTRACT

The present study was conducted from July 1, 2020 to September 25, 2020 in a dedicated coronavirus disease 2019 (COVID-19) hospital in Delhi, India to provide evidence for the presence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus in atmospheric air and surfaces of the hospital wards. Swabs from hospital surfaces (patient's bed, ward floor, and nursing stations area) and suspended particulate matter in ambient air were collected by a portable air sampler from the medicine ward, intensive care unit, and emergency ward admitting COVID-19 patients. By performing reverse-transcriptase polymerase chain reaction (RT-PCR) for E-gene and RdRp gene, SARS-CoV-2 virus was detected from hospital surfaces and particulate matters from the ambient air of various wards collected at 1 and 3-m distance from active COVID-19 patients. The presence of the virus in the air beyond a 1-m distance from the patients and surfaces of the hospital indicates that the SARS-CoV-2 virus has the potential to be transmitted by airborne and surface routes from COVID-19 patients to health-care workers working in COVID-19 dedicated hospital. This warrants that precautions against airborne and surface transmission of COVID-19 in the community should be taken when markets, industries, educational institutions, and so on, reopen for normal activities.


Subject(s)
COVID-19 Nucleic Acid Testing/methods , COVID-19/epidemiology , COVID-19/transmission , Fomites/virology , RNA, Viral/genetics , SARS-CoV-2/genetics , Air/analysis , COVID-19/prevention & control , Coronavirus Envelope Proteins/genetics , Coronavirus RNA-Dependent RNA Polymerase/genetics , Hospitals , Humans , India/epidemiology , Intensive Care Units , Particulate Matter/analysis
18.
Eur J Epidemiol ; 36(7): 685-707, 2021 Jul.
Article in English | MEDLINE | ID: covidwho-1326830

ABSTRACT

Coronavirus disease (COVID-19) is a respiratory disease affecting many people and able to be transmitted through direct and perhaps indirect contact. Direct contact transmission, mediated by aerosols or droplets, is widely demonstrated, whereas indirect transmission is only supported by collateral evidence such as virus persistence on inanimate surfaces and data from other similar viruses. The present systematic review aims to estimate SARS-CoV-2 prevalence on inanimate surfaces, identifying risk levels according to surface characteristics. Data were obtained from studies in published papers collected from two databases (PubMed and Embase) with the last search on 1 September 2020. Included studies had to be papers in English, had to deal with coronavirus and had to consider inanimate surfaces in real settings. Studies were coded according to our assessment of the risk that the investigated surfaces could be contaminated by SARS-CoV-2. A meta-analysis and a metaregression were carried out to quantify virus RNA prevalence and to identify important factors driving differences among studies. Thirty-nine out of forty retrieved paper reported studies carried out in healthcare settings on the prevalence of virus RNA, five studies carry out also analyses through cell culture and six tested the viability of isolated viruses. Overall prevalences of SARS-CoV-2 RNA on high-, medium- and low-risk surfaces were 0.22 (CI95 [0.152-0.296]), 0.04 (CI95 [0.007-0.090]), and 0.00 (CI95 [0.00-0.019]), respectively. The duration surfaces were exposed to virus sources (patients) was the main factor explaining differences in prevalence.


Subject(s)
COVID-19 , Equipment Contamination , Fomites/virology , RNA, Viral/isolation & purification , SARS-CoV-2/isolation & purification , Humans , Microbial Viability , Prevalence
19.
Int J Sports Med ; 42(12): 1058-1069, 2021 Nov.
Article in English | MEDLINE | ID: covidwho-1306501

ABSTRACT

A review of literature on the role of fomites in transmission of coronaviruses informed the development of a framework which was used to qualitatively analyse a cricket case study, where equipment is shared and passed around, and identify potential mitigation strategies. A range of pathways were identified that might in theory allow coronavirus transmission from an infected person to a non-infected person via communal or personal equipment fomites or both. Eighteen percent of potential fomite based interactions were found to be non-essential to play including all contact with another persons equipment. Six opportunities to interrupt the transmission pathway were identified, including the recommendation to screen participants for symptoms prior to play. Social distancing between participants and avoiding unnecessary surface contact provides two opportunities; firstly to avoid equipment exposure to infected respiratory droplets and secondly to avoid uninfected participants touching potential fomites. Hand sanitisation and equipment sanitisation provide two further opportunities by directly inactivating coronavirus. Preventing players from touching their mucosal membranes with their hands represents the sixth potential interruption. Whilst potential fomite transmission pathways were identified, evidence suggests that viral load will be substantially reduced during surface transfer. Mitigation strategies could further reduce potential fomites, suggesting that by comparison, direct airborne transmission presents the greater risk in cricket.


Subject(s)
COVID-19/transmission , Fomites/virology , Pandemics/prevention & control , Sports Equipment , COVID-19/prevention & control , Hand/virology , Humans , Physical Distancing , Touch
20.
Clin Ter ; 172(4): 268-270, 2021 Jul 05.
Article in English | MEDLINE | ID: covidwho-1304847

ABSTRACT

ABSTRACT: The novel severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) has created havoc worldwide ever since its emergen-ce in December 2019. The current evidence indicates that the virus remains viable in aerosols for hours and on fomites for few days. A little information is available on the topic, the present communication reviews the perseverance and distribution of the novel coronavirus in the aerosol and on various inanimate surfaces so that the appropriate safety measures can be undertaken and the virus protection guidelines may be framed accordingly.


Subject(s)
Aerosols , COVID-19/prevention & control , Coronavirus Infections/prevention & control , Disinfectants/pharmacology , Fomites/virology , SARS-CoV-2/drug effects , Safety Management/methods , Humans
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