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1.
Biomed Instrum Technol ; 54(6): 410-416, 2020 Nov 01.
Article in English | MEDLINE | ID: covidwho-1076411

ABSTRACT

The COVID-19 pandemic, caused by severe acute respiratory syndrome coronavirus 2, has challenged healthcare providers in maintaining the supply of critical personal protective equipment, including single-use respirators and surgical masks. Single-use respirators and surgical masks can reduce risks from the inhalation of airborne particles and microbial contamination. The recent high-volume demand for single-use respirators and surgical masks has resulted in many healthcare facilities considering processing to address critical shortages. The dry heat process of 80°C (176°F) for two hours (120 min) has been confirmed to be an appropriate method for single-use respirator and surgical mask processing.


Subject(s)
/prevention & control , Decontamination/methods , Equipment Reuse , Hot Temperature , Masks , Humans , Pandemics , Personal Protective Equipment/supply & distribution
2.
Sci Rep ; 11(1): 1820, 2021 01 19.
Article in English | MEDLINE | ID: covidwho-1065931

ABSTRACT

RT-LAMP detection of SARS-CoV-2 has been shown to be a valuable approach to scale up COVID-19 diagnostics and thus contribute to limiting the spread of the disease. Here we present the optimization of highly cost-effective in-house produced enzymes, and we benchmark their performance against commercial alternatives. We explore the compatibility between multiple DNA polymerases with high strand-displacement activity and thermostable reverse transcriptases required for RT-LAMP. We optimize reaction conditions and demonstrate their applicability using both synthetic RNA and clinical patient samples. Finally, we validate the optimized RT-LAMP assay for the detection of SARS-CoV-2 in unextracted heat-inactivated nasopharyngeal samples from 184 patients. We anticipate that optimized and affordable reagents for RT-LAMP will facilitate the expansion of SARS-CoV-2 testing globally, especially in sites and settings where the need for large scale testing cannot be met by commercial alternatives.


Subject(s)
/diagnosis , Molecular Diagnostic Techniques/methods , Nucleic Acid Amplification Techniques/methods , /genetics , /virology , Hot Temperature , Humans , Nasopharynx/virology , RNA, Viral/metabolism , RNA-Directed DNA Polymerase/metabolism , Reagent Kits, Diagnostic , Sensitivity and Specificity , Virus Inactivation
3.
J Hosp Infect ; 106(3): 536-553, 2020 Nov.
Article in English | MEDLINE | ID: covidwho-1023641

ABSTRACT

BACKGROUND: In pandemics such as COVID-19, shortages of personal protective equipment are common. One solution may be to decontaminate equipment such as facemasks for reuse. AIM: To collect and synthesize existing information on decontamination of N95 filtering facepiece respirators (FFRs) using microwave and heat-based treatments, with special attention to impacts on mask function (aerosol penetration, airflow resistance), fit, and physical traits. METHODS: A systematic review (PROSPERO CRD42020177036) of literature available from Medline, Embase, Global Health, and other sources was conducted. Records were screened independently by two reviewers, and data was extracted from studies that reported on effects of microwave- or heat-based decontamination on N95 FFR performance, fit, physical traits, and/or reductions in microbial load. FINDINGS: Thirteen studies were included that used dry/moist microwave irradiation, heat, or autoclaving. All treatment types reduced pathogen load by a log10 reduction factor of at least three when applied for sufficient duration (>30 s microwave, >60 min dry heat), with most studies assessing viral pathogens. Mask function (aerosol penetration <5% and airflow resistance <25 mmH2O) was preserved after all treatments except autoclaving. Fit was maintained for most N95 models, though all treatment types caused observable physical damage to at least one model. CONCLUSIONS: Microwave irradiation and heat may be safe and effective viral decontamination options for N95 FFR reuse during critical shortages. The evidence does not support autoclaving or high-heat (>90°C) approaches. Physical degradation may be an issue for certain mask models, and more real-world evidence on fit is needed.


Subject(s)
Coronavirus Infections/prevention & control , Decontamination/standards , Equipment Reuse/standards , Guidelines as Topic , Hot Temperature , Respiratory Protective Devices/virology , Ultraviolet Rays , Humans
4.
Chem Biol Interact ; 334: 109339, 2021 Jan 25.
Article in English | MEDLINE | ID: covidwho-970426

ABSTRACT

Clinical trials of thermoheliox application (inhalation with a high-temperature mixture of oxygen and helium, 90 °C) in the treatment of the acute phase of coronavirus infection were conducted. Dynamics of disease development in infected patients (PCR test for the virus) and, dynamics of changes in blood concentration of C-reactive protein, immunoglobulin M, specific immunoglobulin G were studied. High efficiency of thermoheliox in releasing the organism from the virus and stimulating the immune response (thermovaccination effect) was shown. The kinetic model of the process is proposed and analyzed.


Subject(s)
/immunology , Helium/administration & dosage , Hyperthermia, Induced/methods , Oxygen/administration & dosage , Administration, Inhalation , Adult , Aged , Antibodies, Viral/blood , C-Reactive Protein/biosynthesis , Hot Temperature , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Kinetics , Middle Aged , Models, Immunological , Vaccination/methods
5.
Environ Sci Process Impacts ; 23(1): 144-159, 2021 Feb 04.
Article in English | MEDLINE | ID: covidwho-997955

ABSTRACT

The COVID-19 pandemic forced a nationwide lockdown in India for months when close to 1.3 billion people were confined to their homes. An abrupt halt in the majority of the urban activities reduced the generation of anthropogenic heat which often exacerbates the Urban Heat Island (UHI) effect in the urban pockets of the country. We studied the lockdown impact on seven highly populated and polluted mega urban agglomerations across India, namely Delhi, Ahmedabad, Hyderabad, Kolkata, Mumbai, Bengaluru and Chennai, using near-anniversary Landsat 8 data. The results revealed that the lockdowns have improved the air quality and reduced the Land Surface Temperature (LST) and hence the UHI effect over these cities. Each of the cities experienced an improved Air Quality Index (AQI) ranging from 18 to 151 units except Chennai (with a marginal 8 units increase in AQI), a decrease in mean LST in the range of 0.27 °C to 7.06 °C except Kolkata which showed an increment by ∼4 °C, and a reduction in daily averaged air temperature ranging from 0.3 °C to 10.88 °C except Hyderabad which witnessed an increase of 0.09 °C during the lockdown (April 2020) compared to the previous years (April 2019 and 2018). Delhi exhibited the maximum positive impact of the lockdown in all aspects with two-fold improved air quality, and Ahmedabad showed the least improvement. In addition to the variations in regional land use and land cover and proportion of essential industries that remained operational throughout the lockdown, the geographic location, topography, local meteorology and climate were some of the other factors also responsible for either aiding or overcompensating the large scale LST variabilities observed in these cities. These results hint at an unprecedented opportunity to evaluate the effectiveness of periodic planned lockdowns as a possible mitigating measure to reduce LST spikes and degraded air quality in urban areas in the future.


Subject(s)
Hot Temperature , Cities , Communicable Disease Control , Environmental Monitoring , Humans , India , Islands , Pandemics , Temperature
6.
Int J Environ Res Public Health ; 17(21)2020 Nov 03.
Article in English | MEDLINE | ID: covidwho-921196

ABSTRACT

The need for healthcare workers (HCWs) to wear personal protective equipment (PPE) during the coronavirus disease 2019 (COVID-19) pandemic heightens their risk of thermal stress. We assessed the knowledge, attitudes, and practices of HCWs from India and Singapore regarding PPE usage and heat stress when performing treatment and care activities. One hundred sixty-five HCWs from India (n = 110) and Singapore (n = 55) participated in a survey. Thirty-seven HCWs from Singapore provided thermal comfort ratings before and after ice slurry ingestion. Differences in responses between India and Singapore HCWs were compared. A p-value cut-off of 0.05 depicted statistical significance. Median wet-bulb globe temperature was higher in India (30.2 °C (interquartile range [IQR] 29.1-31.8 °C)) than in Singapore (22.0 °C (IQR 18.8-24.8 °C)) (p < 0.001). Respondents from both countries reported thirst (n = 144, 87%), excessive sweating (n = 145, 88%), exhaustion (n = 128, 78%), and desire to go to comfort zones (n = 136, 84%). In Singapore, reports of air-conditioning at worksites (n = 34, 62%), dedicated rest area availability (n = 55, 100%), and PPE removal during breaks (n = 54, 98.2%) were higher than in India (n = 27, 25%; n = 46, 42%; and n = 66, 60%, respectively) (p < 0.001). Median thermal comfort rating improved from 2 (IQR 1-2) to 0 (IQR 0-1) after ice slurry ingestion in Singapore (p < 0.001). HCWs are cognizant of the effects of heat stress but might not adopt best practices due to various constraints. Thermal stress management is better in Singapore than in India. Ice slurry ingestion is shown to be practical and effective in promoting thermal comfort. Adverse effects of heat stress on productivity and judgment of HCWs warrant further investigation.


Subject(s)
Coronavirus Infections , Health Personnel , Hot Temperature , Pandemics , Personal Protective Equipment , Pneumonia, Viral , Stress, Physiological , Adult , Betacoronavirus , Female , Health Knowledge, Attitudes, Practice , Humans , India/epidemiology , Male , Singapore/epidemiology , Surveys and Questionnaires
9.
mSphere ; 5(5)2020 10 21.
Article in English | MEDLINE | ID: covidwho-889854

ABSTRACT

Supply shortages of N95 respirators during the coronavirus disease 2019 (COVID-19) pandemic have motivated institutions to develop feasible and effective N95 respirator reuse strategies. In particular, heat decontamination is a treatment method that scales well and can be implemented in settings with variable or limited resources. Prior studies using multiple inactivation methods, however, have often focused on a single virus under narrowly defined conditions, making it difficult to develop guiding principles for inactivating emerging or difficult-to-culture viruses. We systematically explored how temperature, humidity, and virus deposition solutions impact the inactivation of viruses deposited and dried on N95 respirator coupons. We exposed four virus surrogates across a range of structures and phylogenies, including two bacteriophages (MS2 and phi6), a mouse coronavirus (murine hepatitis virus [MHV]), and a recombinant human influenza A virus subtype H3N2 (IAV), to heat treatment for 30 min in multiple deposition solutions across several temperatures and relative humidities (RHs). We observed that elevated RH was essential for effective heat inactivation of all four viruses tested. For heat treatments between 72°C and 82°C, RHs greater than 50% resulted in a >6-log10 inactivation of bacteriophages, and RHs greater than 25% resulted in a >3.5-log10 inactivation of MHV and IAV. Furthermore, deposition of viruses in host cell culture media greatly enhanced virus inactivation by heat and humidity compared to other deposition solutions, such as phosphate-buffered saline, phosphate-buffered saline with bovine serum albumin, and human saliva. Past and future heat treatment methods must therefore explicitly account for deposition solutions as a factor that will strongly influence observed virus inactivation rates. Overall, our data set can inform the design and validation of effective heat-based decontamination strategies for N95 respirators and other porous surfaces, especially for emerging viruses that may be of immediate and future public health concern.IMPORTANCE Shortages of personal protective equipment, including N95 respirators, during the coronavirus (CoV) disease 2019 (COVID-19) pandemic have highlighted the need to develop effective decontamination strategies for their reuse. This is particularly important in health care settings for reducing exposure to respiratory viruses, like severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), the virus that causes COVID-19. Although several treatment methods are available, a widely accessible strategy will be necessary to combat shortages on a global scale. We demonstrate that the combination of heat and humidity inactivates a range of RNA viruses, including both viral pathogens and common viral pathogen surrogates, after deposition on N95 respirators and achieves the necessary virus inactivation detailed by the U.S. Food and Drug Administration guidelines to validate N95 respirator decontamination technologies. We further demonstrate that depositing viruses onto surfaces when suspended in culture media can greatly enhance observed inactivation, adding caution to how heat and humidity treatment methods are validated.


Subject(s)
Decontamination/methods , Hot Temperature , Humidity , Ventilators, Mechanical , Virus Diseases/prevention & control , Virus Inactivation , Virus Physiological Phenomena , Betacoronavirus , Coronavirus Infections/prevention & control , Humans , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Saline Solution , Saliva , Serum Albumin, Bovine
10.
J Proteome Res ; 19(11): 4428-4441, 2020 11 06.
Article in English | MEDLINE | ID: covidwho-878800

ABSTRACT

Quantitative nuclear magnetic resonance (NMR) spectroscopy of blood plasma is widely used to investigate perturbed metabolic processes in human diseases. The reliability of biochemical data derived from these measurements is dependent on the quality of the sample collection and exact preparation and analysis protocols. Here, we describe systematically, the impact of variations in sample collection and preparation on information recovery from quantitative proton (1H) NMR spectroscopy of human blood plasma and serum. The effects of variation of blood collection tube sizes and preservatives, successive freeze-thaw cycles, sample storage at -80 °C, and short-term storage at 4 and 20 °C on the quantitative lipoprotein and metabolite patterns were investigated. Storage of plasma samples at 4 °C for up to 48 h, freezing at -80 °C and blood sample collection tube choice have few and minor effects on quantitative lipoprotein profiles, and even storage at 4 °C for up to 168 h caused little information loss. In contrast, the impact of heat-treatment (56 °C for 30 min), which has been used for inactivation of SARS-CoV-2 and other viruses, that may be required prior to analytical measurements in low level biosecurity facilities induced marked changes in both lipoprotein and low molecular weight metabolite profiles. It was conclusively demonstrated that this heat inactivation procedure degrades lipoproteins and changes metabolic information in complex ways. Plasma from control individuals and SARS-CoV-2 infected patients are differentially altered resulting in the creation of artifactual pseudo-biomarkers and destruction of real biomarkers to the extent that data from heat-treated samples are largely uninterpretable. We also present several simple blood sample handling recommendations for optimal NMR-based biomarker discovery investigations in SARS CoV-2 studies and general clinical biomarker research.


Subject(s)
Blood Chemical Analysis/standards , Blood Specimen Collection/instrumentation , Coronavirus Infections , Lipoproteins/blood , Magnetic Resonance Spectroscopy/methods , Pandemics , Pneumonia, Viral , Artifacts , Hot Temperature , Humans , Reproducibility of Results
11.
PLoS One ; 15(10): e0240398, 2020.
Article in English | MEDLINE | ID: covidwho-868677

ABSTRACT

Wearing face masks is highly recommended to prevent SARS-CoV-2 transmission in health care workers and for the general public. The demand for high quality face masks has seen an upsurge in the recent times, leading to exploration of alternative economic and easily available options, without compromising on the quality. Particle removal from air in terms of capture efficiency of the filter media or the face mask is a crucial parameter for testing and quality assurance. Short-term reusability of the face masks is also an important aspect as the demand for masks will potentially outstrip the supply in future. Sterilization Wraps, which are used to wrap sterile surgical instruments, have shown a promising performance in terms of removal of particles from air. In this study, we evaluate the particle filtration characteristics of face masks made of 2 different metric weights [45 and 60 gram per square metre (GSM)] respectively, using locally available Sterilization Wraps. The aerosol filtration characteristics were also studied after sterilisation by different techniques such as heat with 50% humidity (thermal treatment), ethylene oxide (ETO), steam and radiation dose of 30kGy. We found that 60 GSM face mask had particle capture efficiency of 94% for total particles greater than 0.3 microns and this capture efficiency was maintained even after sterilisation with ETO and thermal treatment. The cost of producing these masks was 30 US cents/mask at our institute. Our study suggests that sterilization wrap material made of non-woven polypropylene spunbond-meltblown-spunbond (SMS) fibres could be an appropriate readily available inexpensive material for making face masks or N95 respirators.


Subject(s)
Masks/standards , Particle Size , Personal Protective Equipment/standards , Textiles/standards , Aerosols/chemistry , Disinfection/methods , Disinfection/standards , Ethylene Oxide/chemistry , Filtration/standards , Hot Temperature , Humidity , Polypropylenes/chemistry
12.
Proc Natl Acad Sci U S A ; 117(44): 27456-27464, 2020 11 03.
Article in English | MEDLINE | ID: covidwho-867657

ABSTRACT

The virus causing COVID-19 has spread rapidly worldwide and threatens millions of lives. It remains unknown, as of April 2020, whether summer weather will reduce its spread, thereby alleviating strains on hospitals and providing time for vaccine development. Early insights from laboratory studies and research on related viruses predicted that COVID-19 would decline with higher temperatures, humidity, and ultraviolet (UV) light. Using current, fine-scaled weather data and global reports of infections, we develop a model that explains 36% of the variation in maximum COVID-19 growth rates based on weather and demography (17%) and country-specific effects (19%). UV light is most strongly associated with lower COVID-19 growth. Projections suggest that, without intervention, COVID-19 will decrease temporarily during summer, rebound by autumn, and peak next winter. Validation based on data from May and June 2020 confirms the generality of the climate signal detected. However, uncertainty remains high, and the probability of weekly doubling rates remains >20% throughout summer in the absence of social interventions. Consequently, aggressive interventions will likely be needed despite seasonal trends.


Subject(s)
Coronavirus Infections/epidemiology , Pneumonia, Viral/epidemiology , Seasons , Uncertainty , Betacoronavirus , Hot Temperature , Humans , Humidity , Models, Statistical , Pandemics , Ultraviolet Rays
13.
Sci Rep ; 10(1): 17002, 2020 10 12.
Article in English | MEDLINE | ID: covidwho-851311

ABSTRACT

First identified in Wuhan, China, in December 2019, a novel coronavirus (SARS-CoV-2) has affected over 16,800,000 people worldwide as of July 29, 2020 and was declared a pandemic by the World Health Organization on March 11, 2020. Influenza studies have shown that influenza viruses survive longer on surfaces or in droplets in cold and dry air, thus increasing the likelihood of subsequent transmission. A similar hypothesis has been postulated for the transmission of COVID-19, the disease caused by SARS-CoV-2. It is important to propose methodologies to understand the effects of environmental factors on this ongoing outbreak to support decision-making pertaining to disease control. Here, we examine the spatial variability of the basic reproductive numbers of COVID-19 across provinces and cities in China and show that environmental variables alone cannot explain this variability. Our findings suggest that changes in weather (i.e., increase of temperature and humidity as spring and summer months arrive in the Northern Hemisphere) will not necessarily lead to declines in case counts without the implementation of drastic public health interventions.


Subject(s)
Coronavirus Infections/epidemiology , Coronavirus Infections/transmission , Humidity , Pneumonia, Viral/epidemiology , Pneumonia, Viral/transmission , Betacoronavirus , Cold Temperature , Environment , Hot Temperature , Humans , Pandemics , Population Dynamics
14.
J Hosp Infect ; 106(3): 577-584, 2020 Nov.
Article in English | MEDLINE | ID: covidwho-809252

ABSTRACT

BACKGROUND: In the context of the ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, the supply of personal protective equipment remains under severe strain. To address this issue, re-use of surgical face masks and filtering facepiece respirators has been recommended; prior decontamination is paramount to their re-use. AIM: We aim to provide information on the effects of three decontamination procedures on porcine respiratory coronavirus (PRCV)-contaminated masks and respirators, presenting a stable model for infectious coronavirus decontamination of these typically single-use-only products. METHODS: Surgical masks and filtering facepiece respirator coupons and straps were inoculated with infectious PRCV and submitted to three decontamination treatments, ultraviolet (UV) irradiation, vaporized H2O2, and dry heat treatment. Viruses were recovered from sample materials and viral titres were measured in swine testicle cells. FINDINGS: UV irradiation, vaporized H2O2 and dry heat reduced infectious PRCV by more than three orders of magnitude on mask and respirator coupons and rendered it undetectable in all decontamination assays. CONCLUSION: This is the first description of stable disinfection of face masks and filtering facepiece respirators contaminated with an infectious SARS-CoV-2 surrogate using UV irradiation, vaporized H2O2 and dry heat treatment. The three methods permit demonstration of a loss of infectivity by more than three orders of magnitude of an infectious coronavirus in line with the United States Food and Drug Administration policy regarding face masks and respirators. It presents advantages of uncomplicated manipulation and utilization in a BSL2 facility, therefore being easily adaptable to other respirator and mask types.


Subject(s)
Coronavirus Infections/prevention & control , Decontamination/standards , Equipment Reuse/standards , Hot Temperature , Hydrogen Peroxide/standards , Respiratory Protective Devices/virology , Surgical Equipment/standards , Surgical Equipment/virology , Ultraviolet Rays , Guidelines as Topic , Humans
15.
J Microbiol ; 58(10): 886-891, 2020 Oct.
Article in English | MEDLINE | ID: covidwho-807667

ABSTRACT

Various treatments and agents had been reported to inactivate RNA viruses. Of these, thermal inactivation is generally considered an effective and cheap method of sample preparation for downstream assays. The purpose of this study is to establish a safe inactivation method for SARS-CoV-2 without compromising the amount of amplifiable viral genome necessary for clinical diagnoses. In this study, we demonstrate the infectivity and genomic stability of SARSCoV- 2 by thermal inactivation at both 56°C and 65°C. The results substantiate that viable SARS-CoV-2 is readily inactivated when incubated at 56°C for 30 min or at 65°C for 10 min. qRT-PCR of specimens heat-inactivated at 56°C for 30 min or 65°C for 15 min revealed similar genomic RNA stability compared with non-heat inactivated specimens. Further, we demonstrate that 30 min of thermal inactivation at 56°C could inactivate viable viruses from clinical COVID-19 specimens without attenuating the qRT-PCR diagnostic sensitivity. Heat treatment of clinical specimens from COVID-19 patients at 56°C for 30 min or 65°C for 15 min could be a useful method for the inactivation of a highly contagious agent, SARS-CoV-2. Use of this method would reduce the potential for secondary infections in BSL2 conditions during diagnostic procedures. Importantly, infectious virus can be inactivated in clinical specimens without compromising the sensitivity of the diagnostic RT-PCR assay.


Subject(s)
Betacoronavirus/physiology , Coronavirus Infections/diagnosis , Pneumonia, Viral/virology , Specimen Handling/methods , Virus Inactivation , Betacoronavirus/genetics , Betacoronavirus/isolation & purification , Clinical Laboratory Techniques , Coronavirus Infections/virology , Genome, Viral , Genomic Instability , Hot Temperature , Humans , Pandemics , Pneumonia, Viral/diagnosis , RNA, Viral/genetics , Reverse Transcriptase Polymerase Chain Reaction
16.
ACS Nano ; 14(10): 14017-14025, 2020 10 27.
Article in English | MEDLINE | ID: covidwho-779933

ABSTRACT

In March of 2020, the World Health Organization declared a pandemic of coronavirus disease 2019 (COVID-19), caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The pandemic led to a shortage of N95-grade filtering facepiece respirators (FFRs), especially surgical-grade N95 FFRs for protection of healthcare professionals against airborne transmission of SARS-CoV-2. We and others have previously reported promising decontamination methods that may be applied to the recycling and reuse of FFRs. In this study we tested disinfection of three viruses, including SARS-CoV-2, dried on a piece of meltblown fabric, the principal component responsible for filtering of fine particles in N95-level FFRs, under a range of temperatures (60-95 °C) at ambient or 100% relative humidity (RH) in conjunction with filtration efficiency testing. We found that heat treatments of 75 °C for 30 min or 85 °C for 20 min at 100% RH resulted in efficient decontamination from the fabric of SARS-CoV-2, human coronavirus NL63 (HCoV-NL63), and another enveloped RNA virus, chikungunya virus vaccine strain 181/25 (CHIKV-181/25), without lowering the meltblown fabric's filtration efficiency.


Subject(s)
Disinfection/methods , Hot Temperature , Humidity , Masks/virology , Textiles/virology , Betacoronavirus/pathogenicity , Masks/standards , Polypropylenes/chemistry , Textiles/standards
17.
Med Leg J ; 88(1_suppl): 43-46, 2020 Nov.
Article in English | MEDLINE | ID: covidwho-680501

ABSTRACT

Use of appropriate personal protective equipment is essential for healthcare workers when dealing with patients who have tested positive or are suspected of having Covid-19. Personal protective equipment is uncomfortable at best. In hot countries (like India) or in a hot place of work, its wearers are at a high risk of heat-related illnesses. Once in personal protective equipment a healthcare worker can remain in it for at least 6 h at a stretch. In summer when it is hot and humid, personal protective equipment can cause wearer dehydration, heat exhaustion or heat fatigue. In a severe form, this can result in heat stroke and a collapse while on duty. Preventive measures are needed to protect healthcare workers. This review aims to highlight the efficacy and applicability of personal cooling garments.


Subject(s)
Heat Stress Disorders/prevention & control , Hot Temperature , Occupational Exposure/prevention & control , Personal Protective Equipment/statistics & numerical data , Body Temperature Regulation/physiology , Humans , India , Protective Clothing/statistics & numerical data , Tropical Climate
18.
CMAJ ; 192(31): E871-E874, 2020 08 04.
Article in English | MEDLINE | ID: covidwho-639297

ABSTRACT

BACKGROUND: Provision of pasteurized donor human milk, as a bridge to mother's own milk, is the standard of care for very low-birth-weight infants in hospital. The aim of this research was to confirm that Holder pasteurization (62.5°C for 30 min) would be sufficient to inactivate severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in donated human milk samples. METHODS: We spiked frozen milk samples from 10 donors to the Rogers Hixon Ontario Human Milk Bank with SARS-CoV-2 to achieve a final concentration of 1 × 107 TCID50/mL (50% of the tissue culture infectivity dose per mL). We pasteurized samples using the Holder method or held them at room temperature for 30 minutes and plated serial dilutions on Vero E6 cells for 5 days. We included comparative controls in the study using milk samples from the same donors without addition of virus (pasteurized and unpasteurized) as well as replicates of Vero E6 cells directly inoculated with SARS-CoV-2. We reported cytopathic effects as TCID50/mL. RESULTS: We detected no cytopathic activity in any of the SARS-CoV-2-spiked milk samples that had been pasteurized using the Holder method. In the SARS-CoV-2-spiked milk samples that were not pasteurized but were kept at room temperature for 30 minutes, we observed a reduction in infectious viral titre of about 1 log. INTERPRETATION: Pasteurization of human milk by the Holder method (62.5°C for 30 min) inactivates SARS-CoV-2. Thus, in the event that donated human milk contains SARS-CoV-2 by transmission through the mammary gland or by contamination, this method of pasteurization renders milk safe for consumption and handling by care providers.


Subject(s)
Betacoronavirus/growth & development , Coronavirus Infections/prevention & control , Milk Banks , Milk, Human/virology , Pandemics/prevention & control , Pasteurization/methods , Pneumonia, Viral/prevention & control , Virus Inactivation , Hot Temperature , Humans , Milk, Human/chemistry , Ontario , Time Factors , Viral Plaque Assay
19.
Viruses ; 12(7)2020 07 07.
Article in English | MEDLINE | ID: covidwho-639283

ABSTRACT

Standard precautions to minimize the risk of SARS-CoV-2 transmission implies that infected cell cultures and clinical specimens may undergo some sort of inactivation to reduce or abolish infectivity. We evaluated three heat inactivation protocols (56 °C-30 min, 60 °C-60 min and 92 °C-15 min) on SARS-CoV-2 using (i) infected cell culture supernatant, (ii) virus-spiked human sera (iii) and nasopharyngeal samples according to the recommendations of the European norm NF EN 14476-A2. Regardless of the protocol and the type of samples, a 4 Log10 TCID50 reduction was observed. However, samples containing viral loads > 6 Log10 TCID50 were still infectious after 56 °C-30 min and 60 °C-60 min, although infectivity was < 10 TCID50. The protocols 56 °C-30 min and 60 °C-60 min had little influence on the RNA copies detection, whereas 92 °C-15 min drastically reduced the limit of detection, which suggests that this protocol should be avoided for inactivation ahead of molecular diagnostics. Lastly, 56 °C-30 min treatment of serum specimens had a negligible influence on the results of IgG detection using a commercial ELISA test, whereas a drastic decrease in neutralizing titers was observed.


Subject(s)
Betacoronavirus , Containment of Biohazards/methods , Coronavirus Infections/virology , Pneumonia, Viral/virology , Serologic Tests/methods , Virus Inactivation , Antibodies, Neutralizing/immunology , Betacoronavirus/immunology , Containment of Biohazards/standards , Coronavirus Infections/diagnosis , Coronavirus Infections/prevention & control , Enzyme-Linked Immunosorbent Assay , Hot Temperature , Humans , Neutralization Tests , Pandemics/prevention & control , Pneumonia, Viral/diagnosis , Pneumonia, Viral/prevention & control , Serologic Tests/standards
20.
J Hosp Infect ; 106(3): 577-584, 2020 Nov.
Article in English | MEDLINE | ID: covidwho-738455

ABSTRACT

BACKGROUND: In the context of the ongoing severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, the supply of personal protective equipment remains under severe strain. To address this issue, re-use of surgical face masks and filtering facepiece respirators has been recommended; prior decontamination is paramount to their re-use. AIM: We aim to provide information on the effects of three decontamination procedures on porcine respiratory coronavirus (PRCV)-contaminated masks and respirators, presenting a stable model for infectious coronavirus decontamination of these typically single-use-only products. METHODS: Surgical masks and filtering facepiece respirator coupons and straps were inoculated with infectious PRCV and submitted to three decontamination treatments, ultraviolet (UV) irradiation, vaporized H2O2, and dry heat treatment. Viruses were recovered from sample materials and viral titres were measured in swine testicle cells. FINDINGS: UV irradiation, vaporized H2O2 and dry heat reduced infectious PRCV by more than three orders of magnitude on mask and respirator coupons and rendered it undetectable in all decontamination assays. CONCLUSION: This is the first description of stable disinfection of face masks and filtering facepiece respirators contaminated with an infectious SARS-CoV-2 surrogate using UV irradiation, vaporized H2O2 and dry heat treatment. The three methods permit demonstration of a loss of infectivity by more than three orders of magnitude of an infectious coronavirus in line with the United States Food and Drug Administration policy regarding face masks and respirators. It presents advantages of uncomplicated manipulation and utilization in a BSL2 facility, therefore being easily adaptable to other respirator and mask types.


Subject(s)
Coronavirus Infections/prevention & control , Decontamination/standards , Equipment Reuse/standards , Hot Temperature , Hydrogen Peroxide/standards , Respiratory Protective Devices/virology , Surgical Equipment/standards , Surgical Equipment/virology , Ultraviolet Rays , Guidelines as Topic , Humans
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