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1.
Am J Emerg Med ; 49: 172-177, 2021 Nov.
Article in English | MEDLINE | ID: covidwho-1260367

ABSTRACT

BACKGROUND: Airborne personal protective equipment is required for healthcare workers when performing aerosol-generating procedures on patients with infectious diseases. Chest compressions, one of the main components of cardiopulmonary resuscitation, require intense and dynamic movements of the upper body. We aimed to investigate the protective effect of tight-fitting powered air-purifying respirators (PAPRs) during chest compressions. METHODS: This single-center simulation study was performed from February 2021 to March 2021. The simulated workplace protection factor (SWPF) is the concentration ratio of ambient particles and particles inside the PAPR mask; this value indicates the level of protection provided by a respirator when subjected to a simulated work environment. Participants performed continuous chest compressions three times for 2 min each time, with a 4-min break between each session. We measured the SWPF of the tight-fitting PAPR during chest compression in real-time mode. The primary outcome was the ratio of any failure of protection (SWPF <500) during the chest compression sessions. RESULTS: Fifty-four participants completed the simulation. Overall, 78% (n = 42) of the participants failed (the measured SWPF value was less than 500) at least one of the three sessions of chest compressions. The median value and interquartile range of the SWPF was 4304 (685-16,191). There were no reports of slipping down of the respirator or mechanical failure during chest compressions. CONCLUSIONS: Although the median SWPF value was high during chest compressions, the tight-fitting PAPR did not provide adequate protection.


Subject(s)
Cardiopulmonary Resuscitation/adverse effects , Protective Factors , Respiratory Protective Devices/standards , Adult , Air Filters/standards , Air Filters/statistics & numerical data , Cardiopulmonary Resuscitation/methods , Female , Humans , Infection Control/methods , Infection Control/standards , Infection Control/statistics & numerical data , Male , Respiratory Protective Devices/statistics & numerical data , Surveys and Questionnaires
2.
PLoS One ; 16(7): e0254456, 2021.
Article in English | MEDLINE | ID: covidwho-1309962

ABSTRACT

INTRODUCTION: Vaccination programs aim to control the COVID-19 pandemic. However, the relative impacts of vaccine coverage, effectiveness, and capacity in the context of nonpharmaceutical interventions such as mask use and physical distancing on the spread of SARS-CoV-2 are unclear. Our objective was to examine the impact of vaccination on the control of SARS-CoV-2 using our previously developed agent-based simulation model. METHODS: We applied our agent-based model to replicate COVID-19-related events in 1) Dane County, Wisconsin; 2) Milwaukee metropolitan area, Wisconsin; 3) New York City (NYC). We evaluated the impact of vaccination considering the proportion of the population vaccinated, probability that a vaccinated individual gains immunity, vaccination capacity, and adherence to nonpharmaceutical interventions. We estimated the timing of pandemic control, defined as the date after which only a small number of new cases occur. RESULTS: The timing of pandemic control depends highly on vaccination coverage, effectiveness, and adherence to nonpharmaceutical interventions. In Dane County and Milwaukee, if 50% of the population is vaccinated with a daily vaccination capacity of 0.25% of the population, vaccine effectiveness of 90%, and the adherence to nonpharmaceutical interventions is 60%, controlled spread could be achieved by June 2021 versus October 2021 in Dane County and November 2021 in Milwaukee without vaccine. DISCUSSION: In controlling the spread of SARS-CoV-2, the impact of vaccination varies widely depending not only on effectiveness and coverage, but also concurrent adherence to nonpharmaceutical interventions.


Subject(s)
COVID-19 Vaccines/therapeutic use , COVID-19/prevention & control , Patient Compliance/statistics & numerical data , Vaccination Coverage/statistics & numerical data , Computer Simulation , Humans , Masks , Physical Distancing , Respiratory Protective Devices/statistics & numerical data , United States , Urban Health
3.
Epidemiol Prev ; 45(1-2): 110-116, 2021.
Article in Italian | MEDLINE | ID: covidwho-1197717

ABSTRACT

In Italy, the SARS-CoV-2 pandemic showed the devastating consequences of a widespread biological risk not only for the general population, but also for healthcare workers that diagnose COVID-19 and treat patients. In the set of preventive measures taken to reduce this contagion, a fundamental role in personal protection is played by equipment suitable for preventing the contaminated air inhalation. Despite this severe biological risk during the first epidemic phase, some institutional operating protocols and recommendations have shown limitations and contradictions and, therefore, they must not be repeated. It was observed a widespread inadequate use of respiratory protections, such as surgical masks, which show a low efficacy for health workers; adequate respiratory protective devices are instead rarely used, while their use should have been guaranteed more extensively than it is recommended and noticed, according to the current work hygiene legislation.


Subject(s)
COVID-19 , Infectious Disease Transmission, Patient-to-Professional , Pandemics , Respiratory Protective Devices , COVID-19/epidemiology , COVID-19/prevention & control , COVID-19/therapy , COVID-19/transmission , Humans , Infectious Disease Transmission, Patient-to-Professional/prevention & control , Italy/epidemiology , Pandemics/prevention & control , Respiratory Protective Devices/statistics & numerical data , Risk Assessment
4.
Infect Control Hosp Epidemiol ; 42(4): 381-387, 2021 04.
Article in English | MEDLINE | ID: covidwho-1189143

ABSTRACT

OBJECTIVE: To characterize associations between exposures within and outside the medical workplace with healthcare personnel (HCP) SARS-CoV-2 infection, including the effect of various forms of respiratory protection. DESIGN: Case-control study. SETTING: We collected data from international participants via an online survey. PARTICIPANTS: In total, 1,130 HCP (244 cases with laboratory-confirmed COVID-19, and 886 controls healthy throughout the pandemic) from 67 countries not meeting prespecified exclusion (ie, healthy but not working, missing workplace exposure data, COVID symptoms without lab confirmation) were included in this study. METHODS: Respondents were queried regarding workplace exposures, respiratory protection, and extra-occupational activities. Odds ratios for HCP infection were calculated using multivariable logistic regression and sensitivity analyses controlling for confounders and known biases. RESULTS: HCP infection was associated with non-aerosol-generating contact with COVID-19 patients (adjusted OR, 1.4; 95% CI, 1.04-1.9; P = .03) and extra-occupational exposures including gatherings of ≥10 people, patronizing restaurants or bars, and public transportation (adjusted OR range, 3.1-16.2). Respirator use during aerosol-generating procedures (AGPs) was associated with lower odds of HCP infection (adjusted OR, 0.4; 95% CI, 0.2-0.8, P = .005), as was exposure to intensive care and dedicated COVID units, negative pressure rooms, and personal protective equipment (PPE) observers (adjusted OR range, 0.4-0.7). CONCLUSIONS: COVID-19 transmission to HCP was associated with medical exposures currently considered lower-risk and multiple extra-occupational exposures, and exposures associated with proper use of appropriate PPE were protective. Closer scrutiny of infection control measures surrounding healthcare activities and medical settings considered lower risk, and continued awareness of the risks of public congregation, may reduce the incidence of HCP infection.


Subject(s)
COVID-19/transmission , Infectious Disease Transmission, Patient-to-Professional/prevention & control , Adult , Aged , COVID-19/prevention & control , Case-Control Studies , Female , Global Health/statistics & numerical data , Humans , Infectious Disease Transmission, Patient-to-Professional/statistics & numerical data , Logistic Models , Male , Middle Aged , Occupational Exposure/prevention & control , Occupational Exposure/statistics & numerical data , Personal Protective Equipment/statistics & numerical data , Personal Protective Equipment/virology , Respiratory Protective Devices/statistics & numerical data , Respiratory Protective Devices/virology , Young Adult
6.
PLoS One ; 16(2): e0246720, 2021.
Article in English | MEDLINE | ID: covidwho-1088757

ABSTRACT

Filtering facepiece respirators (FFRs) and medical masks are widely used to reduce the inhalation exposure of airborne particulates and biohazardous aerosols. Their protective capacity largely depends on the fraction of these that are filtered from the incoming air volume. While the performance and physics of different filter materials have been the topic of intensive study, less well understood are the effects of mask sealing. To address this, we introduce an approach to calculate the influence of face-seal leakage on filtration ratio and fit factor based on an analytical model and a finite element method (FEM) model, both of which take into account time-dependent human respiration velocities. Using these, we calculate the filtration ratio and fit factor for a range of ventilation resistance values relevant to filter materials, 500-2500 Pa∙s∙m-1, where the filtration ratio and fit factor are calculated as a function of the mask gap dimensions, with good agreement between analytical and numerical models. The results show that the filtration ratio and fit factor are decrease markedly with even small increases in gap area. We also calculate particle filtration rates for N95 FFRs with various ventilation resistances and two commercial FFRs exemplars. Taken together, this work underscores the critical importance of forming a tight seal around the face as a factor in mask performance, where our straightforward analytical model can be readily applied to obtain estimates of mask performance.


Subject(s)
Filtration/methods , Respiratory Protective Devices/statistics & numerical data , Aerosols/analysis , Air Filters , Equipment Design , Finite Element Analysis , Humans , Inhalation Exposure/analysis , Masks/statistics & numerical data , Masks/trends , Materials Testing/methods , Models, Theoretical , N95 Respirators/statistics & numerical data , Particle Size , Respiration , Respiratory Protective Devices/standards , Ventilators, Mechanical/statistics & numerical data , Ventilators, Mechanical/trends
8.
J Hosp Infect ; 108: 55-63, 2021 Feb.
Article in English | MEDLINE | ID: covidwho-988362

ABSTRACT

The coronavirus disease 2019 pandemic has meant that there is growing pressure on hospital resources, not least the availability of appropriate personal protective equipment (PPE), particularly face masks and respirator masks. Within the field of orthopaedic surgery, it is a common sight to see surgeons wearing 'space suits' (SSs) which comprise a helmet, hood and surgical gown. In this study, the authors made modifications to two different SS systems to incorporate a high-efficiency particulate air (HEPA) filter into the fan inlet to assess their potential as re-usable PPE systems for surgeons with regard to protection from a virus spread via respiratory droplets. The testing was carried out using particle counters upstream and downstream on a mannequin wearing two different SS systems with and without modifications to the fan inlet. The results show that using a layer of HEPA filter, cut to size and sealed to the fan inlet in the helmet, will reduce downstream particulates at the user's mouth by >99.5%; this is equivalent to a respirator mask. HEPA filter material is relatively cheap and can be used repeatedly, making this a viable alternative to disposable, and even resterilized, respirator masks in the setting of a respiratory-droplet-spread viral pandemic.


Subject(s)
COVID-19/transmission , Infectious Disease Transmission, Patient-to-Professional/prevention & control , Orthopedic Procedures/standards , Personal Protective Equipment/supply & distribution , Air Filters/statistics & numerical data , Air Filters/trends , COVID-19/diagnosis , COVID-19/epidemiology , COVID-19/virology , Head Protective Devices , Humans , Manikins , Masks , Orthopedic Procedures/statistics & numerical data , Particulate Matter/analysis , Pilot Projects , Respiratory Protective Devices/statistics & numerical data , Respiratory Protective Devices/trends , SARS-CoV-2/genetics , Space Suits/trends , Space Suits/virology
9.
Proc Natl Acad Sci U S A ; 117(51): 32293-32301, 2020 12 22.
Article in English | MEDLINE | ID: covidwho-960373

ABSTRACT

We use the synthetic control method to analyze the effect of face masks on the spread of COVID-19 in Germany. Our identification approach exploits regional variation in the point in time when wearing of face masks became mandatory in public transport and shops. Depending on the region we consider, we find that face masks reduced the number of newly registered severe acute respiratory syndrome coronavirus 2 infections between 15% and 75% over a period of 20 days after their mandatory introduction. Assessing the credibility of the various estimates, we conclude that face masks reduce the daily growth rate of reported infections by around 47%.


Subject(s)
COVID-19/epidemiology , COVID-19/transmission , Masks/statistics & numerical data , COVID-19/prevention & control , COVID-19/virology , Germany/epidemiology , Humans , Respiratory Protective Devices/statistics & numerical data , SARS-CoV-2/genetics , SARS-CoV-2/physiology
10.
J Infect ; 82(1): 1-35, 2021 01.
Article in English | MEDLINE | ID: covidwho-957218

ABSTRACT

OBJECTIVES: To better understand the impact of comprehensive COVID-19 targeted non-pharmaceutical interventions (NPIs) on influenza burden worldwide. METHODS: We conducted a systematic literature search in selected databases (PubMed, WHO COVID-19), preprint servers (medRxiv, bioRxiv) and websites of European Public Health institutes. Documents that compared influenza estimates in the 2019/2020 season with previous seasons were included. Information synthesis was qualitative due to a high heterogeneity in the number and periods of comparative seasons, outcome measures and statistical methods. RESULTS: We included 23 records reporting from 15 countries/regions as well as 8 reports from European Public Health agencies. Estimates in the 2019/2020 season based on influenza virus tests (4 out of 7 countries/regions), defined influenza cases (8 out of 9), influenza positivity rate (7 out of 8), and severe complications (1 out of 2) were lower than in former seasons. Results from syndromic indicators, such as influenza-like-illness (ILI), were less clear or even raised (4 out of 7) after the influenza season indicating a misclassification with COVID-19 cases. CONCLUSIONS: Evidence synthesis suggests that NPIs targeted at SARS-CoV-2-transmission reduce influenza burden as well. Low threshold NPIs need to be more strongly emphasized in influenza prevention strategies.


Subject(s)
COVID-19/prevention & control , Hand Disinfection , Influenza, Human/epidemiology , Influenza, Human/prevention & control , Physical Distancing , Respiratory Protective Devices/statistics & numerical data , COVID-19 Testing , Contact Tracing , Humans , SARS-CoV-2
12.
Eur J Emerg Med ; 28(3): 202-209, 2021 Jun 01.
Article in English | MEDLINE | ID: covidwho-892115

ABSTRACT

BACKGROUND AND IMPORTANCE: Healthcare personnel working in the emergency department (ED) is at risk of acquiring severe acute respiratory syndrome coronavirus-2 (SARS-Cov-2). So far, it is unknown if the reported variety in infection rates among healthcare personnel is related to the use of personal protective equipment (PPE) or other factors. OBJECTIVE: The aim of this study was to investigate the association between PPE use and SARS-CoV-2 infections among ED personnel in the Netherlands. DESIGN, SETTING AND PARTICIPANTS: A nationwide survey, consisting of 42 questions about PPE-usage, ED layout - and workflow and SARS-CoV-2 infection rates of permanent ED staff, was sent to members of the Dutch Society of Emergency Physicians. Members were asked to fill out one survey on behalf of the ED of their hospital. The association between PPE use and the infection rate was investigated using univariable and multivariable regression analyses, adjusting for potential confounders. OUTCOME MEASURES: Primary outcome was the incidence of confirmed SARS-CoV-2 infections among permanent ED staff between 1 March and 15 May 2020. RESULTS: Surveys were sent to 64 EDs of which 45 responded (70.3%). In total, 164 ED staff workers [5.1 (3.2-7.0)%] tested positive for COVID-19 during the study period compared to 0.087% of the general population. There was significant clustering of infected ED staff in some hospitals (range: 0-23 infection). In 13 hospitals, an FFP2 (filtering facepiece particles >94% aerosol filtration) mask or equivalent and eye protection was worn for all contacts with patients with suspected or confirmed SARS-CoV-2 during the whole study period. The unadjusted staff infection rate was higher in these hospitals [7.3 (3.4-11.1) vs. 4.0 (1.9-6.1)%, absolute difference + 3.3%]. Hospital staff testing policy was identified as a potential confounder of the relation between PPE use and confirmed SARS-CoV-2 infections (collinearity statistic 0.95). After adjusting for hospital testing policy, type of PPE was not associated with incidence of COVID 19 infections among ED staff (P = 0.40). CONCLUSION: In this cross-sectional study, the use of high-level PPE (FFP2 or equivalent and eye protection) by ED personnel during all contacts with patients with suspected or confirmed SARS-CoV-2 does not seem to be associated with a lower infection rate of ED staff compared to lower level PPE use. Attention should be paid to ED layout and social distancing to prevent cross-contamination of ED personnel.


Subject(s)
COVID-19/prevention & control , Emergency Service, Hospital/organization & administration , Gloves, Protective/statistics & numerical data , Health Personnel/statistics & numerical data , Infection Control/methods , Personal Protective Equipment/statistics & numerical data , Adult , COVID-19/epidemiology , Cross-Sectional Studies , Female , Health Personnel/psychology , Humans , Male , Netherlands , Protective Clothing/statistics & numerical data , Respiratory Protective Devices/statistics & numerical data , Young Adult
13.
A A Pract ; 14(8): e01264, 2020 Jun.
Article in English | MEDLINE | ID: covidwho-639026

ABSTRACT

Approximately 30% of health care workers (HCWs) fail the respirator fit test. Evidence suggests that addressing face leaks in the 3M respirator enhances its fit and improves its efficacy. Between March 31 and April 9, 2020, HCWs who failed fit tests for 3M 1860 and 1860S respirators were invited to retest with an adhesive modification of the 3M respirator. Sixty-eight percent of HCWs who failed the fit test with their first-choice respirator passed with a modified adhesive respirator. To increase the efficacy and safety of 3M respirators, ineffective face seals need substantial improvement in design.


Subject(s)
Betacoronavirus , Coronavirus Infections/prevention & control , Equipment Design/methods , Health Personnel , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Respiratory Protective Devices/statistics & numerical data , Adhesives , Adult , COVID-19 , Female , Humans , Male , Pilot Projects , SARS-CoV-2
15.
Eur J Med Res ; 25(1): 32, 2020 Aug 12.
Article in English | MEDLINE | ID: covidwho-713821

ABSTRACT

BACKGROUND: The German government has made it mandatory to wear respiratory masks covering mouth and nose (MNC) as an effective strategy to fight SARS-CoV-2 infections. In many countries, this directive has been extended on shopping malls or public transportation. The aim of this paper is to critically analyze the statutory regulation to wear protective masks during the COVID-19 crisis from a medical standpoint. METHODS: We performed an extensive query of the most recent publications addressing the prevention of viral infections including the use of face masks in the community as a method to prevent the spread of the infection. We addressed the issues of practicability, professional use, and acceptability based on the community and the environment where the user resided. RESULTS: Upon our critical review of the available literature, we found only weak evidence for wearing a face mask as an efficient hygienic tool to prevent the spread of a viral infection. However, the use of MNC seems to be linked to relevant protection during close contact scenarios by limiting pathogen-containing aerosol and liquid droplet dissemination. Importantly, we found evidence for significant respiratory compromise in patients with severe obstructive pulmonary disease, secondary to the development of hypercapnia. This could also happen in patients with lung infections, with or without SARS-CoV-2. CONCLUSION: Epidemiologists currently emphasize that wearing MNC will effectively interrupt airborne infections in the community. The government and the politicians have followed these recommendations and used them to both advise and, in some cases, mandate the general population to wear MNC in public locations. Overall, the results seem to suggest that there are some clinically relevant scenarios where the use of MNC necessitates more defined recommendations. Our critical evaluation of the literature both highlights the protective effects of certain types of face masks in defined risk groups, and emphasizes their potential risks.


Subject(s)
Coronavirus Infections/prevention & control , Masks/statistics & numerical data , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Practice Guidelines as Topic , Pre-Exposure Prophylaxis/methods , Respiratory Protective Devices/statistics & numerical data , COVID-19 , Coronavirus Infections/epidemiology , Coronavirus Infections/transmission , Equipment and Supplies Utilization/legislation & jurisprudence , Equipment and Supplies Utilization/statistics & numerical data , Humans , Masks/adverse effects , Pneumonia, Viral/epidemiology , Pneumonia, Viral/transmission , Pre-Exposure Prophylaxis/legislation & jurisprudence , Respiratory Protective Devices/adverse effects
16.
J Hosp Infect ; 106(2): 277-282, 2020 Oct.
Article in English | MEDLINE | ID: covidwho-704916

ABSTRACT

BACKGROUND: The shortage of single-use N95 respirator masks (NRMs) during the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has prompted consideration of NRM recycling to extend limited stocks by healthcare providers and facilities. AIM: To assess potential reuse via autoclaving of NRMs worn daily in a major urban Canadian hospital. METHODS: NRM reusability was assessed following collection from volunteer staff after 2-8 h use, sterilization by autoclaving and PortaCount fit testing. A workflow was developed for reprocessing hundreds of NRMs daily. FINDINGS: Used NRMs passed fit testing after autoclaving once, with 86% passing a second reuse/autoclave cycle. A separate cohort of used masks pre-warmed before autoclaving passed fit testing. To recycle 200-1000 NRMs daily, procedures for collection, sterilization and re-distribution were developed to minimize particle aerosolization risk during NRM handling, to reject NRM showing obvious wear, and to promote adoption by staff. NRM recovery ranged from 49% to 80% across 12 collection cycles. CONCLUSION: Reuse of NRMs is feasible in major hospitals and other healthcare facilities. In sharp contrast to studies of unused NRMs passing fit testing after 10 autoclave cycles, we show that daily wear substantially reduces NRM fit, limiting reuse to a single cycle, but still increasing NRM stocks by ∼66%. Such reuse requires development of a comprehensive plan that includes communication across staffing levels, from front-line workers to hospital administration, to increase the collection, acceptance of and adherence to sterilization processes for NRM recovery.


Subject(s)
Coronavirus Infections/prevention & control , Equipment Design/standards , Equipment Reuse/standards , Hospitals, Urban/standards , Infection Control/standards , Masks/standards , Pandemics/prevention & control , Pneumonia, Viral/prevention & control , Respiratory Protective Devices/standards , Ventilators, Mechanical/standards , Betacoronavirus , COVID-19 , Canada/epidemiology , Coronavirus Infections/epidemiology , Equipment Design/statistics & numerical data , Equipment Reuse/statistics & numerical data , Hospitals, Urban/statistics & numerical data , Humans , Infection Control/methods , Masks/statistics & numerical data , Occupational Exposure/standards , Occupational Exposure/statistics & numerical data , Pneumonia, Viral/epidemiology , Respiratory Protective Devices/statistics & numerical data , SARS-CoV-2 , Ventilators, Mechanical/statistics & numerical data
18.
Respir Med ; 171: 106085, 2020 09.
Article in English | MEDLINE | ID: covidwho-640297

ABSTRACT

BACKGROUND: Chronic respiratory diseases are risk factors for severe disease in coronavirus disease 2019 (COVID-19). Respiratory tract infection is one of the commonest causes of acute exacerbation of chronic obstructive pulmonary disease (AECOPD). There has not been evidence suggesting the link between COVID-19 and AECOPD, especially in places with dramatic responses in infection control with universal masking and aggressive social distancing. METHODS: This is a retrospective study to assess the number of admissions of AECOPD in the first three months of 2020 in Queen Mary Hospital with reference to the admissions in past five years. Log-linear model was used for statistical inference of covariates, including percentage of masking, air quality health index and air temperature. RESULTS: The number of admissions for AECOPD significantly decreased by 44.0% (95% CI 36.4%-52.8%, p < 0.001) in the first three months of 2020 compared with the monthly average admission in 2015-2019. Compare to same period of previous years, AECOPD decreased by 1.0% with each percent of increased masking (p < 0.001) and decreased by 3.0% with increase in 1 °C in temperature (p = 0.045). The numbers of admissions for control diagnoses (heart failure, intestinal obstruction and iron deficiency anaemia) in the same period in 2020 were not reduced. CONCLUSIONS: The number of admissions for AECOPD decreased in first three months of 2020, compared with previous years. This was observed with increased masking percentage and social distancing in Hong Kong. We postulated universal masking and social distancing during COVID-19 pandemics both contributed in preventing respiratory tract infections hence AECOPD.


Subject(s)
COVID-19 , Coronavirus Infections , Pandemics , Patient Admission/statistics & numerical data , Pneumonia, Viral , Pulmonary Disease, Chronic Obstructive , Respiratory Tract Infections , Air Pollution/analysis , Betacoronavirus/isolation & purification , COVID-19/epidemiology , COVID-19/therapy , Coronavirus Infections/epidemiology , Coronavirus Infections/therapy , Female , Hong Kong/epidemiology , Humans , Male , Middle Aged , Pneumonia, Viral/epidemiology , Pneumonia, Viral/therapy , Pulmonary Disease, Chronic Obstructive/epidemiology , Pulmonary Disease, Chronic Obstructive/therapy , Respiratory Protective Devices/statistics & numerical data , Respiratory Tract Infections/epidemiology , Respiratory Tract Infections/etiology , Respiratory Tract Infections/prevention & control , Retrospective Studies , Risk Factors , SARS-CoV-2 , Symptom Flare Up
19.
J Occup Environ Hyg ; 17(9): 408-415, 2020 Sep.
Article in English | MEDLINE | ID: covidwho-640124

ABSTRACT

The routes of COVID-19 transmission to healthcare personnel from infected patients is the subject of debate, but is critical to the selection of personal protective equipment. The objective of this paper was to explore the contributions of three transmission routes-contact, droplet, and inhalation-to the risk of occupationally acquired COVID-19 infection among healthcare personnel (HCP). The method was quantitative microbial risk assessment, and an exposure model, where possible model parameters were based on data specific to the SARS-CoV-2 virus when available. The key finding was that droplet and inhalation transmission routes predominate over the contact route, contributing 35%, 57%, and 8.2% of the probability of infection, on average, without use of personal protective equipment. On average, 80% of inhalation exposure occurs when HCP are near patients. The relative contribution of droplet and inhalation depends upon the emission of SARS-CoV-2 in respirable particles (<10 µm) through exhaled breath, and inhalation becomes predominant, on average, when emission exceeds five gene copies per min. The predicted concentration of SARS-CoV-2 in the air of the patient room is low (< 1 gene copy per m3 on average), and likely below the limit of quantification for many air sampling methods. The findings demonstrate the value of respiratory protection for HCP, and that field sampling may not be sensitive enough to verify the contribution of SARS-CoV-2 inhalation to the risk of occupationally acquired COVID-19 infection among healthcare personnel. The emission and infectivity of SARS-CoV-2 in respiratory droplets of different sizes is a critical knowledge gap for understanding and controlling COVID-19 transmission.


Subject(s)
Coronavirus Infections/epidemiology , Coronavirus Infections/transmission , Health Personnel , Infectious Disease Transmission, Patient-to-Professional/prevention & control , Personal Protective Equipment/statistics & numerical data , Pneumonia, Viral/epidemiology , Pneumonia, Viral/transmission , Respiratory Protective Devices/statistics & numerical data , Animals , Betacoronavirus , COVID-19 , Humans , Infection Control/instrumentation , Markov Chains , Mice , Models, Theoretical , Pandemics , SARS-CoV-2
20.
J Hosp Infect ; 106(2): 283-294, 2020 Oct.
Article in English | MEDLINE | ID: covidwho-636625

ABSTRACT

BACKGROUND: The high demand for personal protective equipment during the novel coronavirus outbreak has prompted the need to develop strategies to conserve supply. Little is known regarding decontamination interventions to allow for surgical mask reuse. AIM: To identify and synthesize data from original research evaluating interventions to decontaminate surgical masks for the purpose of reuse. METHODS: MEDLINE, Embase, CENTRAL, Global Health, the WHO COVID-19 database, Google Scholar, DisasterLit, preprint servers, and prominent journals from inception to April 8th, 2020, were searched for prospective original research on decontamination interventions for surgical masks. Citation screening was conducted independently in duplicate. Study characteristics, interventions, and outcomes were extracted from included studies by two independent reviewers. Outcomes of interest included impact of decontamination interventions on surgical mask performance and germicidal effects. FINDINGS: Seven studies met eligibility criteria: one evaluated the effects of heat and chemical interventions applied after mask use on mask performance, and six evaluated interventions applied prior to mask use to enhance antimicrobial properties and/or mask performance. Mask performance and germicidal effects were evaluated with heterogeneous test conditions. Safety outcomes were infrequently evaluated. Mask performance was best preserved with dry heat decontamination. Good germicidal effects were observed in salt-, N-halamine-, and nanoparticle-coated masks. CONCLUSION: There is limited evidence on the safety or efficacy of surgical mask decontamination. Given the heterogeneous methods used in studies to date, we are unable to draw conclusions on the most efficacious and safe intervention for decontaminating surgical masks.


Subject(s)
Coronavirus Infections/prevention & control , Decontamination/standards , Equipment Reuse/standards , Guidelines as Topic , Masks/standards , Pandemics/prevention & control , Personal Protective Equipment/standards , Pneumonia, Viral/prevention & control , Respiratory Protective Devices/standards , Betacoronavirus , COVID-19 , Decontamination/methods , Equipment Reuse/statistics & numerical data , Humans , Masks/statistics & numerical data , Personal Protective Equipment/statistics & numerical data , Prospective Studies , Respiratory Protective Devices/statistics & numerical data , SARS-CoV-2
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