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Brock RC, Goudie RJB, Peters C, Thaxter R, Gouliouris T, Illingworth CJR, Morris AC, Beggs CB, Butler M, Keevil VL. Efficacy of Air Cleaning Units for preventing SARS-CoV-2 and other hospital-acquired infections on medicine for older people wards: A quasi-experimental controlled before-and- after study. J Hosp Infect 2024:S0195-6701(24)00325-6. [PMID: 39374708 DOI: 10.1016/j.jhin.2024.09.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2024] [Revised: 09/23/2024] [Accepted: 09/25/2024] [Indexed: 10/09/2024]
Abstract
BACKGROUND Nosocomial infections are costly and airborne transmission is increasingly recognised as important for spread. Air Cleaning Units (ACUs) may reduce transmission but little research has focused on their effectiveness on open wards. AIM Assess whether ACUs reduce nosocomial SARS-CoV-2, or other, infections on older adult inpatient wards. METHODS Quasi-experimental before-after study on two intervention-control ward pairs in a UK teaching hospital. Infections were identified using routinely collected electronic health records data during one year of ACU implementation and the preceding year ("core study period"). Extended analyses included 6 months additional data from one ward pair following ACU removal. Hazard ratios (HR) were estimated through Cox regression controlling for age, sex, ward and background infection risk. Time the ACUs were switched on was also recorded for intervention ward 2. FINDINGS ACUs were initially feasible but compliance reduced towards the end of the study (average operation in first vs second half of ACU time on intervention ward 2: 77% vs 53%). 8171 admissions >48hrs (6112 patients, median age 85yrs) were included. Overall, incidence of ward-acquired SARS-CoV-2 was 3.8%. ACU implementation was associated with a non-significant trend of lower hazard for SARS-CoV-2 infection (HR core study period 0.90, 95% CI 0.53, 1.52; extended study period 0.78, 95% CI 0.53, 1.14). Only 1.5% of admissions resulted in other notable ward-acquired infections. CONCLUSION ACUs may reduce SARS-CoV-2 infection to a clinically-meaningfully degree. Larger studies could reduce uncertainty, perhaps using a cross-over design, and factors influencing acceptability to staff and patients should be further explored.
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Affiliation(s)
- Rebecca C Brock
- MRC Biostatistics Unit, School of Clinical Medicine, University of Cambridge, Cambridge. UK
| | - Robert J B Goudie
- MRC Biostatistics Unit, School of Clinical Medicine, University of Cambridge, Cambridge. UK
| | - Christine Peters
- Department of Microbiology, NHS Greater Glasgow and Clyde, Glasgow, UK
| | - Rachel Thaxter
- Infection Control, Cambridge University Hospitals, Cambridge. UK
| | - Theodore Gouliouris
- Department of Infectious Diseases, Cambridge University Hospitals, Cambridge. UK; Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge. UK
| | | | - Andrew Conway Morris
- Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge. UK; The John Farman ICU, Cambridge University Hospitals, Cambridge. UK
| | - Clive B Beggs
- Carnegie School of Sport, Headingley Campus, Leeds Beckett University, Leeds, UK; Department of Medicine for the Elderly, Cambridge University Hospitals, Cambridge. UK
| | - Matthew Butler
- Department of Medicine for the Elderly, Cambridge University Hospitals, Cambridge. UK
| | - Victoria L Keevil
- Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge. UK; Department of Medicine for the Elderly, Cambridge University Hospitals, Cambridge. UK.
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Pan Z, Ou Q, Romay FJ, Chen W, Liang Y, Pui DYH. Experimental and Numerical Investigation of Slip Effect on Nanofiber Filter Performance at Low Pressures. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2024:e2406619. [PMID: 39358969 DOI: 10.1002/smll.202406619] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/01/2024] [Revised: 09/20/2024] [Indexed: 10/04/2024]
Abstract
Nanofiber filters are widely used in air filtration applications due to their superior performance over microfiber filters. Velocity slip around nanofibers has been identified as a key factor contributing to their high figure of merit, yet its impact on filter performance, especially particle collection efficiency, remains unclear due to the difficulty in isolating the slip effect as the sole variable. This study combines experimental and simulation methods to investigate the slip effect by adjusting the air molecule mean free path, rather than varying fiber size as done in previous studies. Filter media with mean fiber sizes ranging from 16.2 to 0.084 µm are utilized. An image-based regression method is developed to address the challenge of determining the solidity of thin nanofiber layers. The results show that the slip effect is enhanced as the testing pressure decreases, reducing pressure drop by less than 15% for microfiber filters and over 50% for nanofiber filters ≈100 nm. The enhanced slip effect at low pressures (i.e., relatively low pressure compared to the ambient environment) significantly improves filtration efficiency, especially for particles larger than 100 nm. It also proposes semi-empirical equations for predicting filter performance in slip and transition flow regimes.
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Affiliation(s)
- Zhengyuan Pan
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Qisheng Ou
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Francisco J Romay
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Weiqi Chen
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Yun Liang
- State Key Laboratory of Pulp and Paper Engineering, South China University of Technology, Guangzhou, 510640, China
| | - David Y H Pui
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
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Katz A, Li T, James LL, Buhariwala P, Osei-Twum JA, Siegel J, O'Campo P. Emergency Knowledge Translation, COVID-19 and indoor air: evaluating a virtual ventilation and filtration consultation program for community spaces in Ontario. BMC Public Health 2024; 24:2682. [PMID: 39354403 PMCID: PMC11443783 DOI: 10.1186/s12889-024-20151-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2023] [Accepted: 09/20/2024] [Indexed: 10/03/2024] Open
Abstract
BACKGROUND An October, 2021 review of Public Health Ontario's COVID-19 guidance for congregate settings such as shelters and long-term care homes demonstrated that this guidance did not include references to ventilation or filtration. In April 2022, an interdisciplinary team with expertise in indoor air quality (IAQ), engineering, epidemiology, community programming and knowledge translation launched a virtual ventilation and filtration consultation program for community spaces in Toronto, Ontario. The program gives people working in community spaces direct access to IAQ experts through 25-min online appointments. The program aims to help reduce the risk of COVID-19 transmission in community spaces, and was designed to help compensate for gaps in public health guidance and action. METHODS Representatives from participating organizations (n. 27) received a link to an online survey via email in April 2023. Survey questions explored the impacts of the program on topics such as: purchase and use of portable air filters; maintenance and use of bathroom fans; and, maintenance and modification of HVAC systems. Survey participation was anonymous, and no demographic information was collected from participants. RESULTS Representatives from 11 organizations completed the survey (40%). Of those who responded, nine (82%) made changes as a result of the program, with eight (73%) making two or more changes such as purchasing portable air filters and increasing routine maintenance of HVAC systems. CONCLUSIONS When presented with brief access to expert support and tailored plain language guidance, people working in community spaces increased their use of ventilation and filtration strategies for COVID-19 infection prevention and control.
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Affiliation(s)
- Amy Katz
- MAP, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada.
- Faculty of Information, University of Toronto, Toronto, ON, Canada.
| | - Tianyuan Li
- Department of Civil and Environmental Engineering, University of Waterloo, Waterloo, ON, Canada
| | - LLana James
- Anansi Health & Innovation Consortium, Toronto, Canada
- Department of Biomedical and Molecular Sciences and School of Rehabilitation Therapy, Queen's University, Kingston, ON, Canada
| | - Pearl Buhariwala
- MAP, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada
| | - Jo-Ann Osei-Twum
- Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
| | - Jeffrey Siegel
- Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
- Department of Civil and Mineral Engineering, University of Toronto, Toronto, ON, Canada
| | - Patricia O'Campo
- MAP, St. Michael's Hospital, Unity Health Toronto, Toronto, ON, Canada
- Dalla Lana School of Public Health, University of Toronto, Toronto, ON, Canada
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4
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Plastiras OE, Bouquet P, Raczkiewicz I, Belouzard S, Martin De Fourchambault E, Dhainaut J, Dacquin JP, Goffard A, Volkringer C. Virucidal activity of porphyrin-based metal-organic frameworks against highly pathogenic coronaviruses and hepatitis C virus. Mater Today Bio 2024; 28:101165. [PMID: 39221218 PMCID: PMC11364898 DOI: 10.1016/j.mtbio.2024.101165] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2024] [Revised: 07/06/2024] [Accepted: 07/27/2024] [Indexed: 09/04/2024] Open
Abstract
The antiviral effect of four porphyrin-based Metal-Organic Frameworks (PMOFs) with Al and Zr, namely Al-TCPP, PCN-222, PCN-223 and PCN-224 was assessed for the first time against HCoV-229E, two highly pathogenic coronaviruses (SARS-CoV-2 and MERS-CoV) and hepatitis C virus (HCV). Infection tests in vitro were done under dark or light exposure for different contact times, and it was found that 15 min of light exposure were enough to give antiviral properties to the materials, therefore inactivating HCoV-229E by 99.98 % and 99.96 % for Al-TCPP and PCN-222. Al-TCPP diminished the viral titer of SARS-CoV-2 greater than PCN-222 in the same duration of light exposure, having an effect of 99.95 % and 93.48 % respectively. Next, Al-TCPP was chosen as the best candidate possessing antiviral properties and was tested against MERS-CoV and HCV, showcasing a reduction of infectivity of 99.28 % and 98.15 % respectively for each virus. The mechanism of the antiviral activity of the four PMOFs was found to be the production of singlet oxygen 1O2 from the porphyrin ligand TCPP when exposed to visible light, by using sodium azide (NaN3) as a scavenger, that can later attack the phospholipids on the envelope of the viruses, thus preventing their entry into the cells.
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Affiliation(s)
- Orfeas-Evangelos Plastiras
- Unité de Catalyse et Chimie du Solide (UCCS), Univ. Lille, CNRS, Centrale Lille, Univ. Artois, F-59000, Lille, France
- U1019, UMR 9017, CIIL - Center for Infection and Immunity of Lille, Institut Pasteur de Lille, Université de Lille, CNRS, INSERM, CHU de Lille, 59000, Lille, France
| | - Peggy Bouquet
- Clinical Microbiology Unit, Institut Pasteur de Lille, Lille, F-59000, France
| | - Imelda Raczkiewicz
- U1019, UMR 9017, CIIL - Center for Infection and Immunity of Lille, Institut Pasteur de Lille, Université de Lille, CNRS, INSERM, CHU de Lille, 59000, Lille, France
| | - Sandrine Belouzard
- U1019, UMR 9017, CIIL - Center for Infection and Immunity of Lille, Institut Pasteur de Lille, Université de Lille, CNRS, INSERM, CHU de Lille, 59000, Lille, France
| | - Esther Martin De Fourchambault
- U1019, UMR 9017, CIIL - Center for Infection and Immunity of Lille, Institut Pasteur de Lille, Université de Lille, CNRS, INSERM, CHU de Lille, 59000, Lille, France
| | - Jeremy Dhainaut
- Unité de Catalyse et Chimie du Solide (UCCS), Univ. Lille, CNRS, Centrale Lille, Univ. Artois, F-59000, Lille, France
| | - Jean-Philippe Dacquin
- Unité de Catalyse et Chimie du Solide (UCCS), Univ. Lille, CNRS, Centrale Lille, Univ. Artois, F-59000, Lille, France
| | - Anne Goffard
- U1019, UMR 9017, CIIL - Center for Infection and Immunity of Lille, Institut Pasteur de Lille, Université de Lille, CNRS, INSERM, CHU de Lille, 59000, Lille, France
| | - Christophe Volkringer
- Unité de Catalyse et Chimie du Solide (UCCS), Univ. Lille, CNRS, Centrale Lille, Univ. Artois, F-59000, Lille, France
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Gilham EL, Raja AI, van Veldhoven K, Nicholls G, Sandys V, Atkinson B, Spencer A, Nicholls I, Cooke J, Bennett A, Morgan D, Keen C, Fletcher T, Pearce N, Manley P, Brickley EB, Chen Y. A SARS-CoV-2 outbreak in a public order and safety training facility in England, June 2021. Ann Work Expo Health 2024; 68:770-776. [PMID: 38785326 DOI: 10.1093/annweh/wxae038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Accepted: 04/24/2024] [Indexed: 05/25/2024] Open
Abstract
BACKGROUND The public order and safety (POS) sector remains susceptible to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) outbreaks, as workplace attendance is typically compulsory and close physical contact is often needed. Here, we report on a SARS-CoV-2 outbreak with an attack rate of 39% (9/23), which occurred between 19 and 29 June 2021 among a cohort of new POS recruits participating in a mandatory 18-week training programme in England. METHODS The COVID-OUT (COVID-19 Outbreak investigation to Understand Transmission) study team undertook a multidisciplinary outbreak investigation, including viral surface sampling, workplace environmental assessment, participant viral and antibody testing, and questionnaires, at the two associated training facilities between 5 July and 24 August 2021. RESULTS Environmental factors, such as ventilation, were deemed inadequate in some areas of the workplace, with carbon dioxide (CO2) levels exceeding 1,500 ppm on multiple occasions within naturally ventilated classrooms. Activities during safety training required close contact, with some necessitating physical contact, physical exertion, and shouting. Furthermore, most participants reported having physical contact with colleagues (67%) and more than one close work contact daily (97%). CONCLUSIONS Our investigation suggests that site- and activity-specific factors likely contributed to the transmission risks within the POS trainee cohort. Potential interventions for mitigating SARS-CoV-2 transmission in this POS training context could include implementing regular rapid lateral flow testing, optimizing natural ventilation, using portable air cleaning devices in classrooms, and expanding use of well-fitted FFP2/FFP3 respirators during activities where prolonged close physical contact is required.
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Affiliation(s)
- Ellie L Gilham
- Rapid Investigation Team, Field Services, UK Health Security Agency, Wellington House, Waterloo Road, London, United Kingdom
| | - Amber I Raja
- Health Equity Action Lab, Department of Infectious Disease Epidemiology & International Health, London School of Hygiene & Tropical Medicine, Keppel Street, London, United Kingdom
| | - Karin van Veldhoven
- Department of Non-communicable Disease Epidemiology, London School of Hygiene & Tropical Medicine, Keppel Street, London, United Kingdom
| | - Gillian Nicholls
- Science Division, Health and Safety Executive, Harpur Hill, Buxton, United Kingdom
| | - Vince Sandys
- Science Division, Health and Safety Executive, Harpur Hill, Buxton, United Kingdom
| | - Barry Atkinson
- Research and Evaluation, UK Health Security Agency, Porton Down, Salisbury, United Kingdom
| | - Antony Spencer
- Research and Evaluation, UK Health Security Agency, Porton Down, Salisbury, United Kingdom
| | - Ian Nicholls
- Research and Evaluation, UK Health Security Agency, Porton Down, Salisbury, United Kingdom
| | - Joan Cooke
- Science Division, Health and Safety Executive, Harpur Hill, Buxton, United Kingdom
| | - Allan Bennett
- Research and Evaluation, UK Health Security Agency, Porton Down, Salisbury, United Kingdom
| | - Derek Morgan
- Science Division, Health and Safety Executive, Harpur Hill, Buxton, United Kingdom
| | - Chris Keen
- Science Division, Health and Safety Executive, Harpur Hill, Buxton, United Kingdom
| | - Tony Fletcher
- Chemical and Environmental Effects Department, UK Health Security Agency, Harwell Campus, Chilton, United Kingdom
| | - Neil Pearce
- Department of Medical Statistics, London School of Hygiene & Tropical Medicine, Keppel Street, London, United Kingdom
| | - Petra Manley
- Rapid Investigation Team, Field Services, UK Health Security Agency, Wellington House, Waterloo Road, London, United Kingdom
| | - Elizabeth B Brickley
- Health Equity Action Lab, Department of Infectious Disease Epidemiology & International Health, London School of Hygiene & Tropical Medicine, Keppel Street, London, United Kingdom
| | - Yiqun Chen
- Science Division, Health and Safety Executive, Harpur Hill, Buxton, United Kingdom
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Marr LC, Samet JM. Reducing Transmission of Airborne Respiratory Pathogens: A New Beginning as the COVID-19 Emergency Ends. ENVIRONMENTAL HEALTH PERSPECTIVES 2024; 132:55001. [PMID: 38728219 PMCID: PMC11086747 DOI: 10.1289/ehp13878] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2023] [Revised: 04/10/2024] [Accepted: 04/17/2024] [Indexed: 05/12/2024]
Abstract
BACKGROUND In response to the COVID-19 pandemic, new evidence-based strategies have emerged for reducing transmission of respiratory infections through management of indoor air. OBJECTIVES This paper reviews critical advances that could reduce the burden of disease from inhaled pathogens and describes challenges in their implementation. DISCUSSION Proven strategies include assuring sufficient ventilation, air cleaning by filtration, and air disinfection by germicidal ultraviolet (UV) light. Layered intervention strategies are needed to maximize risk reduction. Case studies demonstrate how to implement these tools while also revealing barriers to implementation. Future needs include standards designed with infection resilience and equity in mind, buildings optimized for infection resilience among other drivers, new approaches and technologies to improve ventilation, scientific consensus on the amount of ventilation needed to achieve a desired level of risk, methods for evaluating new air-cleaning technologies, studies of their long-term health effects, workforce training on ventilation systems, easier access to federal funds, demonstration projects in schools, and communication with the public about the importance of indoor air quality and actions people can take to improve it. https://doi.org/10.1289/EHP13878.
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Affiliation(s)
- Linsey C. Marr
- The Charles E. Via, Jr. Department of Civil & Environmental Engineering, Virginia Polytechnic Institute and State University, Blacksburg, Virginia, USA
| | - Jonathan M. Samet
- Departments of Epidemiology and Environmental and Occupational Health, Colorado School of Public Health, Aurora, Colorado, USA
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Banholzer N, Jent P, Bittel P, Zürcher K, Furrer L, Bertschinger S, Weingartner E, Ramette A, Egger M, Hascher T, Fenner L. Air Cleaners and Respiratory Infections in Schools: A Modeling Study Based on Epidemiologic, Environmental, and Molecular Data. Open Forum Infect Dis 2024; 11:ofae169. [PMID: 38665173 PMCID: PMC11045022 DOI: 10.1093/ofid/ofae169] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Accepted: 03/19/2024] [Indexed: 04/28/2024] Open
Abstract
Background Using a multiple-measurement approach, we examined the real-world effectiveness of portable HEPA air filtration devices (air cleaners) in a school setting. Methods We collected data over 7 weeks during winter 2022/2023 in 2 Swiss secondary school classes: environmental (CO2, particle concentrations), epidemiologic (absences related to respiratory infections), audio (coughing), and molecular (bioaerosol and saliva samples). Using a crossover design, we compared particle concentrations, coughing, and risk of infection with and without air cleaners. Results All 38 students participated (age, 13-15 years). With air cleaners, mean particle concentration decreased by 77% (95% credible interval, 63%-86%). There were no differences in CO2 levels. Absences related to respiratory infections were 22 without air cleaners vs 13 with them. Bayesian modeling suggested a reduced risk of infection, with a posterior probability of 91% and a relative risk of 0.73 (95% credible interval, 0.44-1.18). Coughing also tended to be less frequent (posterior probability, 93%), indicating that fewer symptomatic students were in class. Molecular analysis detected mainly non-SARS-CoV-2 viruses in saliva (50/448 positive) but not in bioaerosols (2/105) or on the HEPA filters of the air cleaners (4/160). The molecular detection rate in saliva was similar with and without air cleaners. Spatiotemporal analysis of positive saliva samples identified several likely transmissions. Conclusions Air cleaners improved air quality and showed potential benefits in reducing respiratory infections. Airborne detection of non-SARS-CoV-2 viruses was rare, suggesting that these viruses may be more difficult to detect in the air. Future studies should examine the importance of close contact and long-range transmission and the cost-effectiveness of using air cleaners.
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Affiliation(s)
- Nicolas Banholzer
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Philipp Jent
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
- Department of Infectious Diseases, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Pascal Bittel
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Kathrin Zürcher
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Lavinia Furrer
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Simon Bertschinger
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
| | - Ernest Weingartner
- Institute for Sensors and Electronics, University of Applied Sciences and Arts Northwestern Switzerland, Windisch, Switzerland
| | - Alban Ramette
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Matthias Egger
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
- Population Health Sciences, University of Bristol, Bristol, UK
- Centre for Infectious Disease Epidemiology and Research, University of Cape Town, Cape Town, South Africa
| | - Tina Hascher
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
- Institute of Educational Science, University of Bern, Bern, Switzerland
| | - Lukas Fenner
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
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Ebrahimifakhar A, Poursadegh M, Hu Y, Yuill DP, Luo Y. A systematic review and meta-analysis of field studies of portable air cleaners: Performance, user behavior, and by-product emissions. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:168786. [PMID: 38008326 DOI: 10.1016/j.scitotenv.2023.168786] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 11/08/2023] [Accepted: 11/20/2023] [Indexed: 11/28/2023]
Abstract
Indoor air quality is important for the health of building occupants, and public interest in controlling indoor airborne pathogens increased dramatically with the COVID-19 pandemic. Pollutant concentrations can be controlled locally using portable air cleaners (sometimes called air purifiers), which allow occupants to apply air cleaning technology to meet their needs in the location and times that they find appropriate. This paper provides a systematic review of scientific literature that describes field studies of the effectiveness of portable air cleaners. Over 500 papers were considered, and 148 were reviewed in detail, to extract 35 specific research results (e.g., particulate removal performance) or characteristics (e.g., type of building). These were aggregated to provide an overview of results and approaches to this type of research, and to provide meta-analyses of the results. The review includes: descriptions of the geographical location of the research; rate of publications over time; types of buildings and occupants in the field study; types of air cleaner technology being tested; pollutants being measured; resulting pollutant removal effectiveness; patterns of usage and potential barriers to usage by occupants; and the potential for by-product emissions in some air cleaner technologies. An example result is that 83 of the 148 papers measured reductions in fine particulates (PM2.5) and found a mean reduction of 49 % with standard deviation of 20 %. The aggregated results were approximately normally distributed, ranging from finding no significant reduction up to a maximum above 90 % reduction. Sixteen of the 148 papers considered gaseous pollutants, such as volatile organic compounds, nitrogen dioxide, and ozone; 36 papers considered biological pollutants, such as bacteria, viruses, pollen, fungi, etc. An important challenge, common to several studies, is that occupants run the air cleaners for shorter periods and on low airflow rate settings, because of concerns about noise, drafts, and electricity cost, which significantly reduces air cleaning effectiveness.
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Affiliation(s)
- Amir Ebrahimifakhar
- Delos Labs, Delos, New York, NY 10014, USA; Durham School of Architectural Engineering and Construction, University of Nebraska - Lincoln, 1110 S. 67th Street, Omaha, NE 68182, USA.
| | - Mehrdad Poursadegh
- Durham School of Architectural Engineering and Construction, University of Nebraska - Lincoln, 1110 S. 67th Street, Omaha, NE 68182, USA.
| | - Yifeng Hu
- Durham School of Architectural Engineering and Construction, University of Nebraska - Lincoln, 1110 S. 67th Street, Omaha, NE 68182, USA; Buildings and Transportation Science Division, Oak Ridge National Laboratory, Oak Ridge, TN 37830, USA.
| | - David P Yuill
- Durham School of Architectural Engineering and Construction, University of Nebraska - Lincoln, 1110 S. 67th Street, Omaha, NE 68182, USA.
| | - Yu Luo
- Department of Applied Physics and Applied Mathematics, Columbia University, 500 W. 120th Street, New York, NY 10027, USA.
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9
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Lin KY, Pan SC, Wang JT, Fang CT, Liao CH, Cheng CY, Tseng SH, Yang CH, Chen YC, Chang SC. Preventing and controlling intra-hospital spread of COVID-19 in Taiwan - Looking back and moving forward. J Formos Med Assoc 2024; 123 Suppl 1:S27-S38. [PMID: 37268473 PMCID: PMC10201313 DOI: 10.1016/j.jfma.2023.05.018] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 05/18/2023] [Indexed: 06/04/2023] Open
Abstract
COVID-19 has exposed major weaknesses in the healthcare settings. The surge in COVID-19 cases increases the demands of health care, endangers vulnerable patients, and threats occupational safety. In contrast to a hospital outbreak of SARS leading to a whole hospital quarantined, at least 54 hospital outbreaks following a COVID-19 surge in the community were controlled by strengthened infection prevention and control measures for preventing transmission from community to hospitals as well as within hospitals. Access control measures include establishing triage, epidemic clinics, and outdoor quarantine stations. Visitor access restriction is applied to inpatients to limit the number of visitors. Health monitoring and surveillance is applied to healthcare personnel, including self-reporting travel declaration, temperature, predefined symptoms, and test results. Isolation of the confirmed cases during the contagious period and quarantine of the close contacts during the incubation period are critical for containment. The target populations and frequency of SARS-CoV-2 PCR and rapid antigen testing depend on the level of transmission. Case investigation and contact tracing should be comprehensive to identify the close contacts to prevent further transmission. These facility-based infection prevention and control strategies help reduce hospital transmission of SARS-CoV-2 to a minimum in Taiwan.
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Affiliation(s)
- Kuan-Yin Lin
- Center for Infection Control, National Taiwan University Hospital, Taipei, Taiwan; Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan; Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan
| | - Sung-Ching Pan
- Center for Infection Control, National Taiwan University Hospital, Taipei, Taiwan; Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
| | - Jann-Tay Wang
- Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
| | - Chi-Tai Fang
- Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan; Institute of Epidemiology and Preventive Medicine, College of Public Health, National Taiwan University, Taipei, Taiwan
| | - Chun-Hsing Liao
- Department of Internal Medicine, Far Eastern Memorial Hospital, New Taipei City, Taiwan; School of Medicine, College of Medicine, National Yang Ming Chiao Tung University, Taipei City, Taiwan
| | - Chien-Yu Cheng
- Department of Infectious Diseases, Taoyuan General Hospital, Ministry of Health and Welfare, Taoyuan, Taiwan; Institute of Public Health, College of Medicine, National Yang Ming Chiao Tung University, Taipei, Taiwan
| | - Shu-Hui Tseng
- Taiwan Centers for Disease Control, Ministry of Health and Welfare, Taipei, Taiwan
| | - Chin-Hui Yang
- Taiwan Centers for Disease Control, Ministry of Health and Welfare, Taipei, Taiwan
| | - Yee-Chun Chen
- Center for Infection Control, National Taiwan University Hospital, Taipei, Taiwan; Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan.
| | - Shan-Chwen Chang
- Department of Internal Medicine, National Taiwan University Hospital and National Taiwan University College of Medicine, Taipei, Taiwan
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10
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Banholzer N, Jent P, Bittel P, Zürcher K, Furrer L, Bertschinger S, Weingartner E, Ramette A, Egger M, Hascher T, Fenner L. Air cleaners and respiratory infections in schools: A modeling study using epidemiological, environmental, and molecular data. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.12.29.23300635. [PMID: 38234723 PMCID: PMC10793541 DOI: 10.1101/2023.12.29.23300635] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/19/2024]
Abstract
Background Using a multiple-measurement approach, we examined the real-world effectiveness of portable HEPA-air filtration devices (air cleaners) in a school setting. Methods We collected environmental (CO2, particle concentrations), epidemiological (absences related to respiratory infections), audio (coughing), and molecular data (bioaerosol and saliva samples) over seven weeks during winter 2022/2023 in two Swiss secondary school classes. Using a cross-over study design, we compared particle concentrations, coughing, and the risk of infection with vs without air cleaners. Results All 38 students (age 13-15 years) participated. With air cleaners, mean particle concentration decreased by 77% (95% credible interval 63%-86%). There were no differences in CO2 levels. Absences related to respiratory infections were 22 without vs 13 with air cleaners. Bayesian modeling suggested a reduced risk of infection, with a posterior probability of 91% and a relative risk of 0.73 (95% credible interval 0.44-1.18). Coughing also tended to be less frequent (posterior probability 93%). Molecular analysis detected mainly non-SARS-CoV-2 viruses in saliva (50/448 positive), but not in bioaerosols (2/105 positive) or HEPA-filters (4/160). The detection rate was similar with vs without air cleaners. Spatiotemporal analysis of positive saliva samples identified several likely transmissions. Conclusions Air cleaners improved air quality, showed a potential benefit in reducing respiratory infections, and were associated with less coughing. Airborne detection of non-SARS-CoV-2 viruses was rare, suggesting that these viruses may be more difficult to detect in the air. Future studies should examine the importance of close contact and long-range transmission, and the cost-effectiveness of using air cleaners.
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Affiliation(s)
- Nicolas Banholzer
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Philipp Jent
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
- Department of Infectious Diseases, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Pascal Bittel
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Kathrin Zürcher
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
| | - Lavinia Furrer
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Simon Bertschinger
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
| | - Ernest Weingartner
- Institute for Sensors and Electronics, University of Applied Sciences and Arts Northwestern Switzerland, Windisch, Switzerland
| | - Alban Ramette
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Matthias Egger
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
- Population Health Sciences, University of Bristol, Bristol, UK
- Centre for Infectious Disease Epidemiology and Research, University of Cape Town, Cape Town, South Africa
| | - Tina Hascher
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
- Institute of Educational Science, University of Bern, Bern, Switzerland
| | - Lukas Fenner
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
- Multidisciplinary Center for Infectious Diseases, University of Bern, Bern, Switzerland
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11
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Conly JM, Loeb M. SARS-CoV-2 Exposures at a Large Gathering Event and Acquisition of COVID-19 in the Post-Vaccination Era: A Randomized Trial Is Possible During the Pandemic. Clin Infect Dis 2023; 77:1656-1658. [PMID: 37797309 DOI: 10.1093/cid/ciad609] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2023] [Revised: 09/26/2023] [Accepted: 10/03/2023] [Indexed: 10/07/2023] Open
Affiliation(s)
- John M Conly
- Departments of Medicine, Pathology and Laboratory Medicine, Microbiology, Immunology and Infectious Diseases, O'Brien Institute for Public Health, Snyder Institute for Chronic Diseases, University of Calgary and Alberta Health Services, Calgary, Alberta, Canada
| | - Mark Loeb
- Departments of Pathology and Molecular Medicine and Health Research Methods, Evidence, and Impact, McMaster University, Hamilton, Ontario, Canada
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12
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Cooper BS, Evans S, Jafari Y, Pham TM, Mo Y, Lim C, Pritchard MG, Pople D, Hall V, Stimson J, Eyre DW, Read JM, Donnelly CA, Horby P, Watson C, Funk S, Robotham JV, Knight GM. The burden and dynamics of hospital-acquired SARS-CoV-2 in England. Nature 2023; 623:132-138. [PMID: 37853126 PMCID: PMC10620085 DOI: 10.1038/s41586-023-06634-z] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2021] [Accepted: 09/12/2023] [Indexed: 10/20/2023]
Abstract
Hospital-based transmission had a dominant role in Middle East respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus (SARS-CoV) epidemics1,2, but large-scale studies of its role in the SARS-CoV-2 pandemic are lacking. Such transmission risks spreading the virus to the most vulnerable individuals and can have wider-scale impacts through hospital-community interactions. Using data from acute hospitals in England, we quantify within-hospital transmission, evaluate likely pathways of spread and factors associated with heightened transmission risk, and explore the wider dynamical consequences. We estimate that between June 2020 and March 2021 between 95,000 and 167,000 inpatients acquired SARS-CoV-2 in hospitals (1% to 2% of all hospital admissions in this period). Analysis of time series data provided evidence that patients who themselves acquired SARS-CoV-2 infection in hospital were the main sources of transmission to other patients. Increased transmission to inpatients was associated with hospitals having fewer single rooms and lower heated volume per bed. Moreover, we show that reducing hospital transmission could substantially enhance the efficiency of punctuated lockdown measures in suppressing community transmission. These findings reveal the previously unrecognized scale of hospital transmission, have direct implications for targeting of hospital control measures and highlight the need to design hospitals better equipped to limit the transmission of future high-consequence pathogens.
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Affiliation(s)
- Ben S Cooper
- NDM Centre for Global Health Research, Nuffield Department of Medicine, University of Oxford, Oxford, UK.
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand.
| | - Stephanie Evans
- HCAI, Fungal, AMR, AMU and Sepsis Division, UK Health Security Agency, London, UK
| | - Yalda Jafari
- Centre for Mathematical Modelling of Infectious Diseases, IDE, EPH, London School of Hygiene & Tropical Medicine, London, UK
| | - Thi Mui Pham
- Julius Center for Health Sciences and Primary Care, University Medical Center Utrecht, Utrecht University, Utrecht, The Netherlands
| | - Yin Mo
- NDM Centre for Global Health Research, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
- Division of Infectious Disease, Department of Medicine, National University Hospital, Singapore, Singapore
- Department of Medicine, National University of Singapore, Singapore, Singapore
| | - Cherry Lim
- NDM Centre for Global Health Research, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Mahidol-Oxford Tropical Medicine Research Unit, Faculty of Tropical Medicine, Mahidol University, Bangkok, Thailand
| | - Mark G Pritchard
- NDM Centre for Global Health Research, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Pandemic Sciences Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Diane Pople
- HCAI, Fungal, AMR, AMU and Sepsis Division, UK Health Security Agency, London, UK
| | - Victoria Hall
- HCAI, Fungal, AMR, AMU and Sepsis Division, UK Health Security Agency, London, UK
| | - James Stimson
- HCAI, Fungal, AMR, AMU and Sepsis Division, UK Health Security Agency, London, UK
| | - David W Eyre
- Big Data Institute, Nuffield Department of Population Health, University of Oxford, Oxford, UK
- Oxford University Hospitals NHS Foundation Trust, Oxford, UK
- NIHR Oxford Biomedical Research Centre, University of Oxford, Oxford, UK
- NIHR Health Protection Research Unit in Healthcare Associated Infections and Antimicrobial Resistance at University of Oxford in partnership with UKHSA, Oxford, UK
| | - Jonathan M Read
- Lancaster Medical School, Lancaster University, Lancaster, UK
| | - Christl A Donnelly
- Pandemic Sciences Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
- Department of Statistics, University of Oxford, Oxford, UK
- MRC Centre for Global Infectious Disease Analysis, Department of Infectious Disease Epidemiology, Imperial College London, London, UK
| | - Peter Horby
- Pandemic Sciences Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Conall Watson
- Pandemic Sciences Institute, Nuffield Department of Medicine, University of Oxford, Oxford, UK
| | - Sebastian Funk
- Centre for Mathematical Modelling of Infectious Diseases, IDE, EPH, London School of Hygiene & Tropical Medicine, London, UK
| | - Julie V Robotham
- HCAI, Fungal, AMR, AMU and Sepsis Division, UK Health Security Agency, London, UK
- NIHR Health Protection Research Unit in Healthcare Associated Infections and Antimicrobial Resistance at University of Oxford in partnership with UKHSA, Oxford, UK
| | - Gwenan M Knight
- Centre for Mathematical Modelling of Infectious Diseases, IDE, EPH, London School of Hygiene & Tropical Medicine, London, UK
- AMR Centre, IDE, EPH, London School of Hygiene & Tropical Medicine, London, UK
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13
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Donskey CJ. High technology and low technology measures to reduce risk of SARS-CoV-2 transmission. Am J Infect Control 2023; 51:A126-A133. [PMID: 37890942 DOI: 10.1016/j.ajic.2023.03.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2023] [Accepted: 03/09/2023] [Indexed: 10/29/2023]
Abstract
During the coronavirus disease 2019 (COVID-19) pandemic, a variety of low technology and high technology measures have been proposed to reduce the risk for transmission. Identifying those measures likely to be useful in reducing viral transmission without undue expense or potential for adverse effects has been a challenge for infection control programs. The challenge has been compounded by the lack of tools that can be used to assess the risk for viral transmission in different settings. This review discusses practical tools that can be used to assess ventilation and airflow and evaluates some of the low technology and high technology measures that have been proposed as control measures for COVID-19. Some typical questions posed to infection control programs during the pandemic are presented to illustrate real-world application of the concepts being discussed.
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Affiliation(s)
- Curtis J Donskey
- Geriatric Research, Education and Clinical Center, Louis Stokes Cleveland VA Medical Center, Cleveland, OH; Department of Medicine, Case Western Reserve University School of Medicine, Cleveland, OH.
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14
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Madhusudanan A, Iddon C, Cevik M, Naismith JH, Fitzgerald S. Non-pharmaceutical interventions for COVID-19: a systematic review on environmental control measures. PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2023; 381:20230130. [PMID: 37611631 PMCID: PMC10446906 DOI: 10.1098/rsta.2023.0130] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 06/06/2023] [Indexed: 08/25/2023]
Abstract
The purpose of this review was to identify the effectiveness of environmental control (EC) non-pharmaceutical interventions (NPIs) in reducing transmission of SARS-CoV-2 through conducting a systematic review. EC NPIs considered in this review are room ventilation, air filtration/cleaning, room occupancy, surface disinfection, barrier devices, [Formula: see text] monitoring and one-way-systems. Systematic searches of databases from Web of Science, Medline, EMBASE, preprint servers MedRxiv and BioRxiv were conducted in order to identify studies reported between 1 January 2020 and 1 December 2022. All articles reporting on the effectiveness of ventilation, air filtration/cleaning, room occupancy, surface disinfection, barrier devices, [Formula: see text] monitoring and one-way systems in reducing transmission of SARS-CoV-2 were retrieved and screened. In total, 13 971 articles were identified for screening. The initial title and abstract screening identified 1328 articles for full text review. Overall, 19 references provided evidence for the effectiveness of NPIs: 12 reported on ventilation, 4 on air cleaning devices, 5 on surface disinfection, 6 on room occupancy and 1 on screens/barriers. No studies were found that considered the effectiveness of [Formula: see text] monitoring or the implementation of one-way systems. Many of these studies were assessed to have critical risk of bias in at least one domain, largely due to confounding factors that could have affected the measured outcomes. As a result, there is low confidence in the findings. Evidence suggests that EC NPIs of ventilation, air cleaning devices and reduction in room-occupancy may have a role in reducing transmission in certain settings. However, the evidence was usually of low or very low quality and certainty, and hence the level of confidence ascribed to this conclusion is low. Based on the evidence found, it was not possible to draw any specific conclusions regarding the effectiveness of surface disinfection and the use of barrier devices. From these results, we further conclude that community agreed standards for well-designed epidemiological studies with low risk of bias are needed. Implementation of such standards would enable more confident assessment in the future of the effectiveness of EC NPIs in reducing transmission of SARS-CoV-2 and other pathogens in real-world settings. This article is part of the theme issue 'The effectiveness of non-pharmaceutical interventions on the COVID-19 pandemic: the evidence'.
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Affiliation(s)
| | - Christopher Iddon
- Department of Civil, Environmental and Geomatic Engineering, University College London, WC1E 6BT, London, UK
| | - Muge Cevik
- Department of Infection and Global Health, School of Medicine, University of St Andrews, KY16 9TF, St Andrews, UK
| | | | - Shaun Fitzgerald
- Department of Engineering, University of Cambridge, CB2 1PZ, Cambridge, UK
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15
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Humphreys H, Vos M, Presterl E, Hell M. Greater attention to flexible hospital designs and ventilated clinical facilities are a pre-requisite for coping with the next airborne pandemic. Clin Microbiol Infect 2023; 29:1229-1231. [PMID: 37182640 DOI: 10.1016/j.cmi.2023.05.014] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Revised: 04/21/2023] [Accepted: 05/08/2023] [Indexed: 05/16/2023]
Affiliation(s)
- Hilary Humphreys
- Department of Clinical Microbiology, Royal College of Surgeons in Ireland University of Medicine and Health Sciences, Dublin, Ireland; ESCMID Study Group for Nosocomial Infections (ESGNI), Switzerland.
| | - Margreet Vos
- Department of Medical Microbiology and Infectious Diseases, Erasmus MC University Medical Centre, Rotterdam, the Netherlands; ESCMID Study Group for Nosocomial Infections (ESGNI), Switzerland
| | - Elisabeth Presterl
- Department of Hospital Epidemiology and Infection Control, Vienna General Hospital, Medical University of Vienna, Vienna, Austria; ESCMID Study Group for Nosocomial Infections (ESGNI), Switzerland
| | - Markus Hell
- Department of Clinical Microbiology and Hygiene, Medilab, Academic Teaching Laboratories of the Paracelsus Medical University, Salzburg, Austria; ESCMID Study Group for Nosocomial Infections (ESGNI), Switzerland
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16
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Mongin D, Bürgisser N, Laurie G, Schimmel G, Vu DL, Cullati S, Courvoisier DS. Effect of SARS-CoV-2 prior infection and mRNA vaccination on contagiousness and susceptibility to infection. Nat Commun 2023; 14:5452. [PMID: 37673865 PMCID: PMC10482859 DOI: 10.1038/s41467-023-41109-9] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2023] [Accepted: 08/21/2023] [Indexed: 09/08/2023] Open
Abstract
The immunity conferred by SARS-CoV-2 vaccines and infections reduces the transmission of the virus. To answer how the effect of immunity is shared between a reduction of infectiousness and an increased protection against infection, we examined >50,000 positive cases and >110,000 contacts from Geneva, Switzerland (June 2020 to March 2022). We assessed the association between secondary attack rate (i.e. proportion of new cases among contacts) and immunity from natural infection and/or vaccination, stratifying per four SARS-CoV-2 variants and adjusting for index cases and contacts' socio-demographic characteristics and the propensity of the contacts to be tested. Here we show that immunity protected contacts from infection, rather than reducing infectiousness of index cases. Natural infection conferred the strongest immunity. Hybrid immunity did not surpass recent infection. Although of smaller amplitude, the reduction in infectiousness due to vaccination was less affected by time and by the emergence of new SARS-CoV-2 variants than the susceptibility to infection. These findings support the role of vaccine in reducing infectiousness and underscore the complementary role of interventions reducing SARS-CoV-2 propagation, such as mask use or indoor ventilation.
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Affiliation(s)
- Denis Mongin
- Faculty of Medicine, University of Geneva, Geneva, Switzerland.
| | - Nils Bürgisser
- Faculty of Medicine, University of Geneva, Geneva, Switzerland
- General internal medicine division, Department of Medicine, Geneva University Hospitals, Geneva, Switzerland
| | - Gustavo Laurie
- Division of General cantonal physician, Geneva Directorate of Health, Geneva, Switzerland
| | - Guillaume Schimmel
- Division of General cantonal physician, Geneva Directorate of Health, Geneva, Switzerland
| | - Diem-Lan Vu
- Faculty of Medicine, University of Geneva, Geneva, Switzerland
- Division of General cantonal physician, Geneva Directorate of Health, Geneva, Switzerland
- Division of Infectious Diseases, Geneva University Hospitals, Geneva, Switzerland
- Laboratory of Virology, Division of Laboratory Medicine, Geneva University Hospitals, Geneva, Switzerland
| | - Stephane Cullati
- Division Quality of care, University Hospitals of Geneva, Geneva, Switzerland
- Population Health Laboratory (#PopHealthLab), Faculty of Science and Medicine, University of Fribourg, Fribourg, Switzerland
| | - Delphine Sophie Courvoisier
- Faculty of Medicine, University of Geneva, Geneva, Switzerland
- Division Quality of care, University Hospitals of Geneva, Geneva, Switzerland
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17
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Otter JA, Clark L, Taylor G, Hussein A, Gargee L, Goldenberg SD. Comparative evaluation of stand-alone HEPA-based air decontamination systems. Infect Dis Health 2023; 28:246-248. [PMID: 37263813 PMCID: PMC10229387 DOI: 10.1016/j.idh.2023.05.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Revised: 05/04/2023] [Accepted: 05/05/2023] [Indexed: 06/03/2023]
Affiliation(s)
- Jonathan A Otter
- Guy's and St Thomas' NHS Foundation Trust, Westminster Bridge Road, London, SE1 7EH, UK; National Institute for Healthcare Research Health Protection Research Unit (NIHR HPRU) in HCAI and AMR, Imperial College London & Public Health England, Hammersmith Hospital, Du Cane Road, W12 0HS, UK.
| | - Louise Clark
- Guy's and St Thomas' NHS Foundation Trust, Westminster Bridge Road, London, SE1 7EH, UK
| | | | - Amal Hussein
- Guy's and St Thomas' NHS Foundation Trust, Westminster Bridge Road, London, SE1 7EH, UK
| | - Latchmin Gargee
- Guy's and St Thomas' NHS Foundation Trust, Westminster Bridge Road, London, SE1 7EH, UK
| | - Simon D Goldenberg
- Guy's and St Thomas' NHS Foundation Trust, Westminster Bridge Road, London, SE1 7EH, UK
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18
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Hannon DM, Jones T, Conolly J, Judge C, Iqbal T, Shahzad A, Madden M, Kirrane F, Conneely P, Harte BH, O'Halloran M, Laffey JG. Development and assessment of the performance of a shared ventilatory system that uses clinically available components to individualize tidal volumes. BMC Anesthesiol 2023; 23:239. [PMID: 37454135 PMCID: PMC10349497 DOI: 10.1186/s12871-023-02200-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2023] [Accepted: 07/07/2023] [Indexed: 07/18/2023] Open
Abstract
OBJECTIVES To develop and assess a system for shared ventilation using clinically available components to individualize tidal volumes. DESIGN Evaluation and in vitro validation study SETTING: Ventilator shortage during the SARS-CoV-2 pandemic. PARTICIPANTS The team consisted of physicians, bioengineers, computer programmers, and medical technology professionals. METHODS Using clinically available components, a system of ventilation consisting of two ventilatory limbs was assembled and connected to a ventilator. Monitors for each limb were developed using open-source software. Firstly, the effect of altering ventilator settings on tidal volumes delivered to each limb was determined. Secondly, the impact of altering the compliance and resistance of one limb on the tidal volumes delivered to both limbs was analysed. Experiments were repeated three times to determine system variability. RESULTS The system permitted accurate and reproducible titration of tidal volumes to each limb over a range of ventilator settings and simulated lung conditions. Alteration of ventilator inspiratory pressures, of respiratory rates, and I:E ratio resulted in very similar tidal volumes delivered to each limb. Alteration of compliance and resistance in one limb resulted in reproducible alterations in tidal volume to that test lung, with little change to tidal volumes in the other lung. All tidal volumes delivered were reproducible. CONCLUSIONS We demonstrate the reliability of a shared ventilation system assembled using commonly available clinical components that allows titration of individual tidal volumes. This system may be useful as a strategy of last resort for Covid-19, or other mass casualty situations, where the need for ventilators exceeds supply.
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Affiliation(s)
- David M Hannon
- Department of Anaesthesia, School of Medicine, Galway University Hospitals, University of Galway, Galway, Ireland
- Translational Medical Device Lab, University of Galway, Galway, Ireland
| | - Tim Jones
- Translational Medical Device Lab, University of Galway, Galway, Ireland
| | - Jack Conolly
- Translational Medical Device Lab, University of Galway, Galway, Ireland
| | - Conor Judge
- Translational Medical Device Lab, University of Galway, Galway, Ireland
| | - Talha Iqbal
- Smart Sensors Lab, School of Medicine, University of Galway, Galway, Ireland
| | - Atif Shahzad
- Smart Sensors Lab, School of Medicine, University of Galway, Galway, Ireland
| | - Michael Madden
- School of Computer Science, National University of Ireland Galway, Galway, Ireland
| | - Frank Kirrane
- Department of Medical Physics and Clinical Engineering, Galway University Hospitals, Galway, Ireland
| | - Peter Conneely
- Department of Medical Physics and Clinical Engineering, Galway University Hospitals, Galway, Ireland
| | - Brian H Harte
- Department of Anaesthesia, School of Medicine, Galway University Hospitals, University of Galway, Galway, Ireland
| | - Martin O'Halloran
- Translational Medical Device Lab, University of Galway, Galway, Ireland
- CÚRAM Centre for Research in Medical Devices, Biomedical Sciences Building, University of Galway, Galway, Ireland
| | - John G Laffey
- Department of Anaesthesia, School of Medicine, Galway University Hospitals, University of Galway, Galway, Ireland.
- Translational Medical Device Lab, University of Galway, Galway, Ireland.
- CÚRAM Centre for Research in Medical Devices, Biomedical Sciences Building, University of Galway, Galway, Ireland.
- School of Medicine, Clinical Sciences Institute, University of Galway, Galway, Ireland.
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19
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Chou YA, Wang ZY, Chang HC, Liu YC, Su PF, Huang YT, Yang CT, Lai CH. Indoor CO 2 monitoring in a surgical intensive care unit under visitation restrictions during the COVID-19 pandemic. Front Med (Lausanne) 2023; 10:1052452. [PMID: 37521349 PMCID: PMC10375033 DOI: 10.3389/fmed.2023.1052452] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 06/30/2023] [Indexed: 08/01/2023] Open
Abstract
Background Indoor CO2 concentration is an important metric of indoor air quality (IAQ). The dynamic temporal pattern of CO2 levels in intensive care units (ICUs), where healthcare providers experience high cognitive load and occupant numbers are frequently changing, has not been comprehensively characterized. Objective We attempted to describe the dynamic change in CO2 levels in the ICU using an Internet of Things-based (IoT-based) monitoring system. Specifically, given that the COVID-19 pandemic makes hospital visitation restrictions necessary worldwide, this study aimed to appraise the impact of visitation restrictions on CO2 levels in the ICU. Methods Since February 2020, an IoT-based intelligent indoor environment monitoring system has been implemented in a 24-bed university hospital ICU, which is symmetrically divided into areas A and B. One sensor was placed at the workstation of each area for continuous monitoring. The data of CO2 and other pollutants (e.g., PM2.5) measured under standard and restricted visitation policies during the COVID-19 pandemic were retrieved for analysis. Additionally, the CO2 levels were compared between workdays and non-working days and between areas A and B. Results The median CO2 level (interquartile range [IQR]) was 616 (524-682) ppm, and only 979 (0.34%) data points obtained in area A during standard visitation were ≥ 1,000 ppm. The CO2 concentrations were significantly lower during restricted visitation (median [IQR]: 576 [556-596] ppm) than during standard visitation (628 [602-663] ppm; p < 0.001). The PM2.5 concentrations were significantly lower during restricted visitation (median [IQR]: 1 [0-1] μg/m3) than during standard visitation (2 [1-3] μg/m3; p < 0.001). The daily CO2 and PM2.5 levels were relatively low at night and elevated as the occupant number increased during clinical handover and visitation. The CO2 concentrations were significantly higher in area A (median [IQR]: 681 [653-712] ppm) than in area B (524 [504-547] ppm; p < 0.001). The CO2 concentrations were significantly lower on non-working days (median [IQR]: 606 [587-671] ppm) than on workdays (583 [573-600] ppm; p < 0.001). Conclusion Our study suggests that visitation restrictions during the COVID-19 pandemic may affect CO2 levels in the ICU. Implantation of the IoT-based IAQ sensing network system may facilitate the monitoring of indoor CO2 levels.
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Affiliation(s)
- Ying-An Chou
- Department of Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Zheng-Yao Wang
- Department of Computer Science, Tunghai University, Taichung, Taiwan
- UniSmart Technology Co., Ltd., Taichung, Taiwan
| | - Hsiang-Ching Chang
- Department of Computer Science, Tunghai University, Taichung, Taiwan
- UniSmart Technology Co., Ltd., Taichung, Taiwan
| | - Yi-Chia Liu
- Department of Statistics, College of Management, National Cheng Kung University, Tainan, Taiwan
| | - Pei-Fang Su
- Department of Statistics, College of Management, National Cheng Kung University, Tainan, Taiwan
| | - Yen Ta Huang
- Department of Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
| | - Chao-Tung Yang
- Department of Computer Science, Tunghai University, Taichung, Taiwan
- Research Center for Smart Sustainable Circular Economy, Tunghai University, Taichung, Taiwan
| | - Chao-Han Lai
- Department of Surgery, National Cheng Kung University Hospital, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Biochemistry and Molecular Biology, College of Medicine, National Cheng Kung University, Tainan, Taiwan
- Department of Biostatistics, Vanderbilt University Medical Center, Nashville, TN, United States
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20
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Graham A, Raja AI, van Veldhoven K, Nicholls G, Simpson A, Atkinson B, Nicholls I, Higgins H, Cooke J, Bennett A, Morgan D, Keen C, Fletcher T, Pearce N, Atchison C, Brickley EB, Chen Y. A SARS-CoV-2 outbreak in a plastics manufacturing plant. BMC Public Health 2023; 23:1077. [PMID: 37277762 DOI: 10.1186/s12889-023-16025-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 05/31/2023] [Indexed: 06/07/2023] Open
Abstract
BACKGROUND A SARS-CoV-2 outbreak with an attack rate of 14.3% was reported at a plastics manufacturing plant in England. METHODS Between 23rd March and 13th May 2021, the COVID-OUT team undertook a comprehensive outbreak investigation, including environmental assessment, surface sampling, molecular and serological testing, and detailed questionnaires, to identify potential SARS-CoV-2 transmission routes, and workplace- and worker-related risk factors. RESULTS While ventilation, indicated using real-time CO2 proxy measures, was generally adequate on-site, the technical office with the highest localized attack rate (21.4%) frequently reached peaks in CO2 of 2100ppm. SARS-CoV-2 RNA was found in low levels (Ct ≥35) in surface samples collected across the site. High noise levels (79dB) were recorded in the main production area, and study participants reported having close work contacts (73.1%) and sharing tools (75.5%). Only 20.0% of participants reported using a surgical mask and/or FFP2/FFP3 respirator at least half the time and 71.0% expressed concerns regarding potential pay decreases and/or unemployment due to self-isolation or workplace closure. CONCLUSIONS The findings reinforce the importance of enhanced infection control measures in manufacturing sectors, including improved ventilation with possible consideration of CO2 monitoring, utilising air cleaning interventions in enclosed environments, and provision of good-quality face masks (i.e., surgical masks or FFP2/FFP3 respirators) especially when social distancing cannot be maintained. Further research on the impacts of job security-related concerns is warranted.
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Affiliation(s)
- Alice Graham
- Rapid Investigation Team, Field Services, UK Health Security Agency, Wellington House, London, UK
| | - Amber I Raja
- Health Equity Action Lab, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | - Karin van Veldhoven
- Department of Non-communicable Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | | | - Andrew Simpson
- Science Division, Health and Safety Executive, Buxton, UK
| | - Barry Atkinson
- Chemical and Environmental Effects Department, UK Health Security Agency, Chilton, UK
| | - Ian Nicholls
- Chemical and Environmental Effects Department, UK Health Security Agency, Chilton, UK
| | - Hannah Higgins
- Rapid Investigation Team, Field Services, UK Health Security Agency, Wellington House, London, UK
| | - Joan Cooke
- Science Division, Health and Safety Executive, Buxton, UK
| | - Allan Bennett
- Chemical and Environmental Effects Department, UK Health Security Agency, Chilton, UK
| | - Derek Morgan
- Science Division, Health and Safety Executive, Buxton, UK
| | - Chris Keen
- Science Division, Health and Safety Executive, Buxton, UK
| | - Tony Fletcher
- Chemical and Environmental Effects Department, UK Health Security Agency, Chilton, UK
| | - Neil Pearce
- Department of Medical Statistics, London School of Hygiene & Tropical Medicine, London, UK
| | - Christina Atchison
- Rapid Investigation Team, Field Services, UK Health Security Agency, Wellington House, London, UK
| | - Elizabeth B Brickley
- Health Equity Action Lab, Department of Infectious Disease Epidemiology, London School of Hygiene & Tropical Medicine, London, UK
| | - Yiqun Chen
- Science Division, Health and Safety Executive, Buxton, UK.
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21
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Banholzer N, Zürcher K, Jent P, Bittel P, Furrer L, Egger M, Hascher T, Fenner L. SARS-CoV-2 transmission with and without mask wearing or air cleaners in schools in Switzerland: A modeling study of epidemiological, environmental, and molecular data. PLoS Med 2023; 20:e1004226. [PMID: 37200241 PMCID: PMC10194935 DOI: 10.1371/journal.pmed.1004226] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/19/2023] [Accepted: 03/28/2023] [Indexed: 05/20/2023] Open
Abstract
BACKGROUND Growing evidence suggests an important contribution of airborne transmission to the overall spread of Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2), in particular via smaller particles called aerosols. However, the contribution of school children to SARS-CoV-2 transmission remains uncertain. The aim of this study was to assess transmission of airborne respiratory infections and the association with infection control measures in schools using a multiple-measurement approach. METHODS AND FINDINGS We collected epidemiological (cases of Coronavirus Disease 2019 (COVID-19)), environmental (CO2, aerosol and particle concentrations), and molecular data (bioaerosol and saliva samples) over 7 weeks from January to March 2022 (Omicron wave) in 2 secondary schools (n = 90, average 18 students/classroom) in Switzerland. We analyzed changes in environmental and molecular characteristics between different study conditions (no intervention, mask wearing, air cleaners). Analyses of environmental changes were adjusted for different ventilation, the number of students in class, school and weekday effects. We modeled disease transmission using a semi-mechanistic Bayesian hierarchical model, adjusting for absent students and community transmission. Molecular analysis of saliva (21/262 positive) and airborne samples (10/130) detected SARS-CoV-2 throughout the study (weekly average viral concentration 0.6 copies/L) and occasionally other respiratory viruses. Overall daily average CO2 levels were 1,064 ± 232 ppm (± standard deviation). Daily average aerosol number concentrations without interventions were 177 ± 109 1/cm3 and decreased by 69% (95% CrI 42% to 86%) with mask mandates and 39% (95% CrI 4% to 69%) with air cleaners. Compared to no intervention, the transmission risk was lower with mask mandates (adjusted odds ratio 0.19, 95% CrI 0.09 to 0.38) and comparable with air cleaners (1.00, 95% CrI 0.15 to 6.51). Study limitations include possible confounding by period as the number of susceptible students declined over time. Furthermore, airborne detection of pathogens document exposure but not necessarily transmission. CONCLUSIONS Molecular detection of airborne and human SARS-CoV-2 indicated sustained transmission in schools. Mask mandates were associated with greater reductions in aerosol concentrations than air cleaners and with lower transmission. Our multiple-measurement approach could be used to continuously monitor transmission risk of respiratory infections and the effectiveness of infection control measures in schools and other congregate settings.
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Affiliation(s)
- Nicolas Banholzer
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
| | - Kathrin Zürcher
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
| | - Philipp Jent
- Department of Infectious Diseases, Inselspital, Bern University Hospital, University of Bern, Bern, Switzerland
| | - Pascal Bittel
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Lavinia Furrer
- Institute for Infectious Diseases, University of Bern, Bern, Switzerland
| | - Matthias Egger
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
- Centre for Infectious Disease Epidemiology and Research, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
- Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
| | - Tina Hascher
- Institute of Educational Science, University of Bern, Bern, Switzerland
| | - Lukas Fenner
- Institute of Social and Preventive Medicine, University of Bern, Bern, Switzerland
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22
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Conway Morris A, Smielewska A. Viral infections in critical care: a narrative review. Anaesthesia 2023; 78:626-635. [PMID: 36633460 PMCID: PMC10952373 DOI: 10.1111/anae.15946] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/23/2022] [Indexed: 01/13/2023]
Abstract
Viral infections form a substantial part of the intensive care workload, even before the recent and ongoing COVID-19 pandemic. The growing availability of molecular diagnostics for viral infections has led to increased recognition of these pathogens. This additional information, however, provides new challenges for interpretation and management. As the SARS-CoV-2 pandemic has amply demonstrated, the emergence and global spread of novel viruses are likely to provide continued challenges for critical care physicians into the future. This article will provide an overview of viral infections relevant to the critical care physician, discussing the diagnosis and management of respiratory viral infections, blood borne and enteric viruses. We will also discuss herpesviridae complications, commonly seen due to reactivation of latent infections. Further, we explore some rarer and emerging viruses, including recognition of viral haemorrhagic fevers, and briefly discuss post-viral syndromes which may present to the intensive care unit. Finally, we will discuss infection control and its importance in preventing nosocomial viral transmission.
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Affiliation(s)
- A. Conway Morris
- Division of Anaesthesia, Department of MedicineUniversity of CambridgeUK
- John V Farman Intensive Care UnitAddenbrooke's HospitalCambridgeUK
| | - A. Smielewska
- Department of Clinical Virology, LCL, CSSBLiverpool University Hospitals NHS Foundation TrustLiverpoolUK
- School of Clinical MedicineUniversity of LiverpoolUK
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23
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Phillips F, Crowley J, Warburton S, Staniforth K, Parra‐Blanco A, Gordon GS. Air filtration mitigates aerosol levels both during and after endoscopy procedures. DEN OPEN 2023; 3:e231. [PMID: 37082739 PMCID: PMC10111116 DOI: 10.1002/deo2.231] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/14/2022] [Revised: 03/02/2023] [Accepted: 03/14/2023] [Indexed: 04/22/2023]
Abstract
Objectives Upper gastrointestinal endoscopies are aerosol-generating procedures, increasing the risk of spreading airborne pathogens. We aim to quantify the mitigation of airborne particles via improved ventilation, specifically laminar flow theatres and portable high-efficiency particulate air (HEPA) filters, during and after upper gastrointestinal endoscopies. Methods This observational study included patients undergoing routine upper gastrointestinal endoscopy in a standard endoscopy room with 15-17 air changes per hour, a standard endoscopy room with a portable HEPA filtration unit, and a laminar flow theatre with 300 air changes per hour. A particle counter (diameter range 0.3 μm-25 μm) took measurements 10 cm from the mouth. Three analyses were performed: whole procedure particle counts, event-based counts, and air clearance estimation using post-procedure counts. Results Compared to a standard endoscopy room, for whole procedures we observe a 28.5x reduction in particle counts in laminar flow (p < 0.001) but no significant effect of HEPA filtration (p = 0.50). For event analysis, we observe for lateral flow theatres reduction in particles >5 μm for oral extubation (12.2x, p < 0.01), reduction in particles <5 μm for coughing/gagging (6.9x, p < 0.05), and reduction for all sizes in anesthetic throat spray (8.4x, p < 0.01) but no significant effect of HEPA filtration. However, we find that in the fallow period between procedures HEPA filtration reduces particle clearance times by 40%. Conclusions Laminar flow theatres are highly effective at dispersing aerosols immediately after production and should be considered for high-risk cases where patients are actively infectious or the supply of personal protective equipment is limited. Portable HEPA filers can safely reduce the fallow time between procedures by 40%.
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Affiliation(s)
- Frank Phillips
- NIHR Nottingham Biomedical Research CentreNottingham University Hospitals NHS Trust and the University of NottinghamNottinghamUK
| | - Jane Crowley
- Department of Electrical and Electronic EngineeringUniversity of NottinghamNottinghamUK
| | - Samantha Warburton
- NIHR Nottingham Biomedical Research CentreNottingham University Hospitals NHS Trust and the University of NottinghamNottinghamUK
| | | | - Adolfo Parra‐Blanco
- NIHR Nottingham Biomedical Research CentreNottingham University Hospitals NHS Trust and the University of NottinghamNottinghamUK
| | - George S.D. Gordon
- Department of Electrical and Electronic EngineeringUniversity of NottinghamNottinghamUK
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24
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Raymenants J, Geenen C, Budts L, Thibaut J, Thijssen M, De Mulder H, Gorissen S, Craessaerts B, Laenen L, Beuselinck K, Ombelet S, Keyaerts E, André E. Indoor air surveillance and factors associated with respiratory pathogen detection in community settings in Belgium. Nat Commun 2023; 14:1332. [PMID: 36898982 PMCID: PMC10005919 DOI: 10.1038/s41467-023-36986-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Accepted: 02/27/2023] [Indexed: 03/12/2023] Open
Abstract
Currently, the real-life impact of indoor climate, human behaviour, ventilation and air filtration on respiratory pathogen detection and concentration are poorly understood. This hinders the interpretability of bioaerosol quantification in indoor air to surveil respiratory pathogens and transmission risk. We tested 341 indoor air samples from 21 community settings in Belgium for 29 respiratory pathogens using qPCR. On average, 3.9 pathogens were positive per sample and 85.3% of samples tested positive for at least one. Pathogen detection and concentration varied significantly by pathogen, month, and age group in generalised linear (mixed) models and generalised estimating equations. High CO2 and low natural ventilation were independent risk factors for detection. The odds ratio for detection was 1.09 (95% CI 1.03-1.15) per 100 parts per million (ppm) increase in CO2, and 0.88 (95% CI 0.80-0.97) per stepwise increase in natural ventilation (on a Likert scale). CO2 concentration and portable air filtration were independently associated with pathogen concentration. Each 100ppm increase in CO2 was associated with a qPCR Ct value decrease of 0.08 (95% CI -0.12 to -0.04), and portable air filtration with a 0.58 (95% CI 0.25-0.91) increase. The effects of occupancy, sampling duration, mask wearing, vocalisation, temperature, humidity and mechanical ventilation were not significant. Our results support the importance of ventilation and air filtration to reduce transmission.
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Affiliation(s)
- Joren Raymenants
- Laboratory of Clinical Microbiology, KU Leuven, Herestraat 49, 3000, Leuven, Belgium.
- Department of General Internal Medicine, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium.
| | - Caspar Geenen
- Laboratory of Clinical Microbiology, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Lore Budts
- Department of Laboratory Medicine, National Reference Center of Respiratory Pathogens, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Jonathan Thibaut
- Laboratory of Clinical Microbiology, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Marijn Thijssen
- Laboratory of Clinical and Epidemiological Virology (Rega Institute), KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Hannelore De Mulder
- Laboratory of Clinical Microbiology, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Sarah Gorissen
- Laboratory of Clinical Microbiology, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Bastiaan Craessaerts
- Department of Laboratory Medicine, National Reference Center of Respiratory Pathogens, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Lies Laenen
- Laboratory of Clinical Microbiology, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
- Department of Laboratory Medicine, National Reference Center of Respiratory Pathogens, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Kurt Beuselinck
- Department of Laboratory Medicine, National Reference Center of Respiratory Pathogens, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Sien Ombelet
- Department of Laboratory Medicine, National Reference Center of Respiratory Pathogens, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Els Keyaerts
- Department of Laboratory Medicine, National Reference Center of Respiratory Pathogens, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium
| | - Emmanuel André
- Laboratory of Clinical Microbiology, KU Leuven, Herestraat 49, 3000, Leuven, Belgium
- Department of Laboratory Medicine, National Reference Center of Respiratory Pathogens, University Hospitals Leuven, Herestraat 49, 3000, Leuven, Belgium
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25
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Loh MM, Yaxley N, Moore G, Holmes D, Todd S, Smith A, Macdonald E, Semple S, Cherrie M, Patel M, Hamill R, Leckie A, Dancer SJ, Cherrie JW. Measurement of SARS-CoV-2 in air and on surfaces in Scottish hospitals. J Hosp Infect 2023; 133:1-7. [PMID: 36473553 PMCID: PMC9721166 DOI: 10.1016/j.jhin.2022.11.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2022] [Revised: 11/27/2022] [Accepted: 11/27/2022] [Indexed: 12/12/2022]
Abstract
BACKGROUND There are still uncertainties in our knowledge of the amount of SARS-CoV-2 virus present in the environment - where it can be found, and potential exposure determinants - limiting our ability to effectively model and compare interventions for risk management. AIM This study measured SARS-CoV-2 in three hospitals in Scotland on surfaces and in air, alongside ventilation and patient care activities. METHODS Air sampling at 200 L/min for 20 min and surface sampling were performed in two wards designated to treat COVID-19-positive patients and two non-COVID-19 wards across three hospitals in November and December 2020. FINDINGS Detectable samples of SARS-CoV-2 were found in COVID-19 treatment wards but not in non-COVID-19 wards. Most samples were below assay detection limits, but maximum concentrations reached 1.7×103 genomic copies/m3 in air and 1.9×104 copies per surface swab (3.2×102 copies/cm2 for surface loading). The estimated geometric mean air concentration (geometric standard deviation) across all hospitals was 0.41 (71) genomic copies/m3 and the corresponding values for surface contamination were 2.9 (29) copies/swab. SARS-CoV-2 RNA was found in non-patient areas (patient/visitor waiting rooms and personal protective equipment changing areas) associated with COVID-19 treatment wards. CONCLUSION Non-patient areas of the hospital may pose risks for infection transmission and further attention should be paid to these areas. Standardization of sampling methods will improve understanding of levels of environmental contamination. The pandemic has demonstrated a need to review and act upon the challenges of older hospital buildings meeting current ventilation guidance.
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Affiliation(s)
- M M Loh
- Institute of Occupational Medicine, Edinburgh, UK.
| | - N Yaxley
- UK Health Security Agency, Porton Down, UK
| | - G Moore
- UK Health Security Agency, Porton Down, UK
| | - D Holmes
- Institute of Occupational Medicine, Edinburgh, UK
| | - S Todd
- Institute of Occupational Medicine, Edinburgh, UK
| | - A Smith
- Institute of Occupational Medicine, Edinburgh, UK
| | | | - S Semple
- Institute for Social Marketing & Health, University of Stirling, Stirling, UK
| | - M Cherrie
- Institute of Occupational Medicine, Edinburgh, UK
| | | | | | | | - S J Dancer
- NHS Lanarkshire, UK; Edinburgh Napier University, UK
| | - J W Cherrie
- Institute of Occupational Medicine, Edinburgh, UK; Heriot Watt University, Edinburgh, UK
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26
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Fennelly M, Hellebust S, Wenger J, O'Connor D, Griffith GW, Plant BJ, Prentice MB. Portable HEPA filtration successfully augments natural-ventilation-mediated airborne particle clearance in a legacy design hospital ward. J Hosp Infect 2023; 131:54-57. [PMID: 36198345 PMCID: PMC9526867 DOI: 10.1016/j.jhin.2022.09.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2022] [Revised: 09/23/2022] [Accepted: 09/26/2022] [Indexed: 01/25/2023]
Abstract
As the severe acute respiratory syndrome coronavirus-2 pandemic has proceeded, ventilation has been recognized increasingly as an important tool in infection control. Many hospitals in Ireland and the UK do not have mechanical ventilation and depend on natural ventilation. The effectiveness of natural ventilation varies with atmospheric conditions and building design. In a challenge test of a legacy design ward, this study showed that portable air filtration significantly increased the clearance of pollutant aerosols of respirable size compared with natural ventilation, and reduced spatial variation in particle persistence. A combination of natural ventilation and portable air filtration is significantly more effective for particle clearance than either intervention alone.
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Affiliation(s)
- M Fennelly
- School of Chemistry and Environmental Research Institute, University College Cork, Cork, Ireland; Department of Pathology, University College Cork, Cork, Ireland; School of Chemical and Pharmaceutical Sciences, Technological University Dublin, Dublin, Ireland.
| | - S Hellebust
- School of Chemistry and Environmental Research Institute, University College Cork, Cork, Ireland
| | - J Wenger
- School of Chemistry and Environmental Research Institute, University College Cork, Cork, Ireland
| | - D O'Connor
- School of Chemical Sciences, Dublin City University, Dublin, Ireland
| | - G W Griffith
- Department of Life Sciences, Aberystwyth University, Aberystwyth, UK
| | - B J Plant
- Adult Cystic Fibrosis Centre, Cork University Hospital, University College Cork, Cork, Ireland
| | - M B Prentice
- Department of Pathology, University College Cork, Cork, Ireland; APC Microbiome Institute, University College Cork, Cork, Ireland.
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27
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Srikrishna D, Karan A, Dhillon RS. SARS-CoV-2 Reduction in Shared Indoor Air. JAMA 2022; 328:2162. [PMID: 36472600 DOI: 10.1001/jama.2022.18028] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
| | - Abraar Karan
- Division of Infectious Diseases and Geographic Medicine, Stanford University, Palo Alto, California
| | - Ranu S Dhillon
- Division of Global Health Equity, Brigham and Women's Hospital, Boston, Massachusetts
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28
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Shrimpton AJ, Pickering AE. Aerosols: time to clear the air? Anaesthesia 2022; 77:1193-1196. [DOI: 10.1111/anae.15864] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 08/25/2022] [Indexed: 11/30/2022]
Affiliation(s)
- A. J. Shrimpton
- Anaesthesia, Pain and Critical Care Sciences, School of Physiology, Pharmacology and Neuroscience University of Bristol UK
| | - A. E. Pickering
- Anaesthesia, Pain and Critical Care Sciences, School of Physiology, Pharmacology and Neuroscience University of Bristol UK
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29
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Srikrishna D. Can 10× cheaper, lower-efficiency particulate air filters and box fans complement High-Efficiency Particulate Air (HEPA) purifiers to help control the COVID-19 pandemic? THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 838:155884. [PMID: 35580674 PMCID: PMC9107182 DOI: 10.1016/j.scitotenv.2022.155884] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/18/2022] [Revised: 05/08/2022] [Accepted: 05/08/2022] [Indexed: 05/29/2023]
Abstract
Public health departments such as CDC and California Department of Public Health (CA-DPH) advise HEPA-purifiers to limit transmission of SARS-CoV-2 indoor spaces. CA-DPH recommends air exchanges per hour (ACH) of 4-6 air for rooms with marginal ventilation and 6-12 in classrooms often necessitating multiple HEPA-purifiers per room, unaffordable in under-resourced community settings. Pressure to seek cheap, rapid air filtration resulted in proliferation of lower-cost, Do-It-Yourself (DIY) air purifiers whose performance is not well characterized compared to HEPA-purifiers. Primary metrics are clean air delivery rate (CADR), noise generated (dBA), and affordability ($$). CADR measurement often requires hard-to-replicate laboratory experiments with generated aerosols. We use simplified, low-cost measurement tools of ambient aerosols enabling scalable evaluation of aerosol filtration efficiencies (0.3 to 10 μm), estimated CADR, and noise generation to compare 3 HEPA-purifiers and 9 DIY purifier designs. DIY purifiers consist of one or two box fans coupled to single MERV 13-16 filters (1″-5″ thick) or quad filters in a cube. Accounting for reduced filtration efficiency of MERV 13-16 filters (versus HEPA) at the most penetrating particle size of 0.3 μm, estimated CADR of DIY purifiers using 2″ (67%), 4″ (66%), and 5″ (85%) filters at lowest fan speed was 293 cfm ($35), 322 cfm ($58), and 405 cfm ($120) comparable to best-in-class, low-noise generating HEPA-purifier running at maximum speed with at 282 cfm ($549). Quad filter designs, popularly known Corsi-Rosenthal boxes, achieved gains in estimated CADR below 80% over single filter designs, less than the 100% gain by adding a second DIY purifier. Replacing one of the four filters with a second fan resulted in gains of 125%-150% in estimated CADR. Tested DIY alternatives using lower-efficiency, single filters compare favorably to tested HEPA-purifiers in estimated CADR, noise generated at five to ten times lower cost, enabling cheap, rapid aerosol removal indoors.
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30
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Fernández de Mera IG, Granda C, Villanueva F, Sánchez‐Sánchez M, Moraga‐Fernández A, Gortázar C, de la Fuente J. HEPA filters of portable air cleaners as a tool for the surveillance of SARS-CoV-2. INDOOR AIR 2022; 32:e13109. [PMID: 36168219 PMCID: PMC9538271 DOI: 10.1111/ina.13109] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 08/20/2022] [Accepted: 08/24/2022] [Indexed: 05/20/2023]
Abstract
Studies about the identification of SARS-CoV-2 in indoor aerosols have been conducted in hospital patient rooms and to a lesser extent in nonhealthcare environments. In these studies, people were already infected with SARS-CoV-2. However, in the present study, we investigated the presence of SARS-CoV-2 in HEPA filters housed in portable air cleaners (PACs) located in places with apparently healthy people to prevent possible outbreaks. A method for detecting the presence of SARS-CoV-2 RNA in HEPA filters was developed and validated. The study was conducted for 13 weeks in three indoor environments: school, nursery, and a household of a social health center, all in Ciudad Real, Spain. The environmental monitoring of the presence of SARS-CoV-2 was conducted in HEPA filters and other surfaces of these indoor spaces for a selective screening in asymptomatic population groups. The objective was to limit outbreaks at an early stage. One HEPA filter tested positive in the social health center. After analysis by RT-PCR of SARS-CoV-2 in residents and healthcare workers, one worker tested positive. Therefore, this study provides direct evidence of virus-containing aerosols trapped in HEPA filters and the possibility of using these PACs for environmental monitoring of SARS-CoV-2 while they remove airborne aerosols and trap the virus.
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Affiliation(s)
- Isabel G. Fernández de Mera
- SaBio, Instituto de Investigación en Recursos Cinegéticos IREC (UCLM‐CSIC‐JCCM)Ronda de ToledoCiudad RealSpain
| | - Carmen Granda
- Residencias CADIG Guadiana I y IICentro de Salud Ciudad Real ISpain
| | - Florentina Villanueva
- Instituto de Investigación en Combustión y Contaminación AtmosféricaUniversidad de Castilla‐La ManchaCiudad RealSpain
- Parque Científico y Tecnológico de Castilla‐La ManchaPaseo de la Innovación 1AlbaceteSpain
| | - Marta Sánchez‐Sánchez
- SaBio, Instituto de Investigación en Recursos Cinegéticos IREC (UCLM‐CSIC‐JCCM)Ronda de ToledoCiudad RealSpain
| | - Alberto Moraga‐Fernández
- SaBio, Instituto de Investigación en Recursos Cinegéticos IREC (UCLM‐CSIC‐JCCM)Ronda de ToledoCiudad RealSpain
| | - Christian Gortázar
- SaBio, Instituto de Investigación en Recursos Cinegéticos IREC (UCLM‐CSIC‐JCCM)Ronda de ToledoCiudad RealSpain
| | - José de la Fuente
- SaBio, Instituto de Investigación en Recursos Cinegéticos IREC (UCLM‐CSIC‐JCCM)Ronda de ToledoCiudad RealSpain
- Department of Veterinary Pathobiology, Center for Veterinary Health SciencesOklahoma State UniversityStillwaterOklahomaUSA
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31
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Kemp SA, Cheng MTK, Hamilton WL, Kamelian K, Singh S, Rakshit P, Agrawal A, Illingworth CJR, Gupta RK. Transmission of B.1.617.2 Delta variant between vaccinated healthcare workers. Sci Rep 2022; 12:10492. [PMID: 35729228 PMCID: PMC9212198 DOI: 10.1038/s41598-022-14411-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2021] [Accepted: 06/07/2022] [Indexed: 01/01/2023] Open
Abstract
Breakthrough infections with SARS-CoV-2 Delta variant have been reported in doubly-vaccinated recipients and as re-infections. Studies of viral spread within hospital settings have highlighted the potential for transmission between doubly-vaccinated patients and health care workers and have highlighted the benefits of high-grade respiratory protection for health care workers. However the extent to which vaccination is preventative of viral spread in health care settings is less well studied. Here, we analysed data from 118 vaccinated health care workers (HCW) across two hospitals in India, constructing two probable transmission networks involving six HCWs in Hospital A and eight HCWs in Hospital B from epidemiological and virus genome sequence data, using a suite of computational approaches. A maximum likelihood reconstruction of transmission involving known cases of infection suggests a high probability that doubly vaccinated HCWs transmitted SARS-CoV-2 between each other and highlights potential cases of virus transmission between individuals who had received two doses of vaccine. Our findings show firstly that vaccination may reduce rates of transmission, supporting the need for ongoing infection control measures even in highly vaccinated populations, and secondly we have described a novel approach to identifying transmissions that is scalable and rapid, without the need for an infection control infrastructure.
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Affiliation(s)
- Steven A Kemp
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Cambridge, UK.,Department of Medicine, University of Cambridge, Cambridge, UK
| | - Mark T K Cheng
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Cambridge, UK
| | | | - Kimia Kamelian
- National Microbiology Laboratory, Public Health Agency of Canada, Winnipeg, MB, Canada
| | | | - Sujit Singh
- National Centre for Disease Control, Delhi, India
| | | | - Anurag Agrawal
- CSIR Institute of Genomics and Integrative Biology, Delhi, India
| | - Christopher J R Illingworth
- Garscube Campus, MRC - University of Glasgow Centre for Virus Research, 464 Bearsden Road, Glasgow, UK. .,MRC Biostatistics Unit, University of Cambridge, East Forvie Building, Forvie Site, Robinson Way, Cambridge, UK. .,Department of Applied Mathematics and Theoretical Physics, University of Cambridge, Cambridge, UK.
| | - Ravindra K Gupta
- Cambridge Institute of Therapeutic Immunology & Infectious Disease (CITIID), Cambridge, UK. .,Department of Medicine, University of Cambridge, Cambridge, UK. .,Africa Health Research Institute, Durban, South Africa. .,Jeffrey Cheah Biomedical Centre, Cambridge, CB5 8UB, UK.
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Survey of coronavirus disease 2019 (COVID-19) infection control policies at leading US academic hospitals in the context of the initial pandemic surge of the severe acute respiratory coronavirus virus 2 (SARS-CoV-2) omicron variant. Infect Control Hosp Epidemiol 2022; 44:597-603. [PMID: 35705223 PMCID: PMC9253430 DOI: 10.1017/ice.2022.155] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
OBJECTIVE To assess coronavirus disease 2019 (COVID-19) infection policies at leading US medical centers in the context of the initial wave of the severe acute respiratory coronavirus virus 2 (SARS-CoV-2) omicron variant. DESIGN Electronic survey study eliciting hospital policies on masking, personal protective equipment, cohorting, airborne-infection isolation rooms (AIIRs), portable HEPA filters, and patient and employee testing. SETTING AND PARTICIPANTS "Hospital epidemiologists from U.S. News top 20 hospitals and 10 hospitals in the CDC Prevention Epicenters program." As it is currently written, it implies all 30 hospitals are from the CDC Prevention Epicenters program, but that only applies to 10 hospitals. Alternatively, we could just say "Hospital epidemiologists from 30 leading US hospitals." METHODS Survey results were reported using descriptive statistics. RESULTS Of 30 hospital epidemiologists surveyed, 23 (77%) completed the survey between February 15 and March 3, 2022. Among the responding hospitals, 18 (78%) used medical masks for universal masking and 5 (22%) used N95 respirators. 16 hospitals (70%) required universal eye protection. 22 hospitals (96%) used N95s for routine COVID-19 care and 1 (4%) reserved N95s for aerosol-generating procedures. 2 responding hospitals (9%) utilized dedicated COVID-19 wards; 8 (35%) used mixed COVID-19 and non-COVID-19 units; and 13 (57%) used both dedicated and mixed units. 4 hospitals (17%) used AIIRs for all COVID-19 patients, 10 (43%) prioritized AIIRs for aerosol-generating procedures, 3 (13%) used alternate risk-stratification criteria (not based on aerosol-generating procedures), and 6 (26%) did not routinely use AIIRs. 9 hospitals (39%) did not use portable HEPA filters, but 14 (61%) used them for various indications, most commonly as substitutes for AIIRs when unavailable or for specific high-risk areas or situations. 21 hospitals (91%) tested asymptomatic patients on admission, but postadmission testing strategies and preferred specimen sites varied substantially. 5 hospitals (22%) required regular testing of unvaccinated employees and 1 hospital (4%) reported mandatory weekly testing even for vaccinated employees during the SARS-CoV-2 omicron surge. CONCLUSIONS COVID-19 infection control practices in leading hospitals vary substantially. Clearer public health guidance and transparency around hospital policies may facilitate more consistent national standards.
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Increased risk of central line-associated bloodstream infection in COVID-19 patients associated with dexamethasone but not with interleukin antagonists. Intensive Care Med 2022; 48:954-957. [PMID: 35670819 PMCID: PMC9171741 DOI: 10.1007/s00134-022-06750-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2022] [Indexed: 12/31/2022]
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Klompas M, Baker M, Rhee C. COVID-19's Challenges to Infection Control Dogma Regarding Respiratory Virus Transmission. Clin Infect Dis 2022; 75:e102-e104. [PMID: 35271714 DOI: 10.1093/cid/ciac204] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2022] [Indexed: 12/29/2022] Open
Affiliation(s)
- Michael Klompas
- Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA.,Department of Medicine, Brigham and Women's Hospital, Boston, MA
| | - Meghan Baker
- Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA.,Department of Medicine, Brigham and Women's Hospital, Boston, MA
| | - Chanu Rhee
- Department of Population Medicine, Harvard Medical School and Harvard Pilgrim Health Care Institute, Boston, MA.,Department of Medicine, Brigham and Women's Hospital, Boston, MA
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Dudding T, Sheikh S, Gregson F, Haworth J, Haworth S, Main BG, Shrimpton AJ, Hamilton FW, Ireland AJ, Maskell NA, Reid JP, Bzdek BR, Gormley M. A clinical observational analysis of aerosol emissions from dental procedures. PLoS One 2022; 17:e0265076. [PMID: 35271682 PMCID: PMC8912243 DOI: 10.1371/journal.pone.0265076] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2021] [Accepted: 02/22/2022] [Indexed: 12/27/2022] Open
Abstract
Aerosol generating procedures (AGPs) are defined as any procedure releasing airborne particles <5 μm in size from the respiratory tract. There remains uncertainty about which dental procedures constitute AGPs. We quantified the aerosol number concentration generated during a range of periodontal, oral surgery and orthodontic procedures using an aerodynamic particle sizer, which measures aerosol number concentrations and size distribution across the 0.5-20 μm diameter size range. Measurements were conducted in an environment with a sufficiently low background to detect a patient's cough, enabling confident identification of aerosol. Phantom head control experiments for each procedure were performed under the same conditions as a comparison. Where aerosol was detected during a patient procedure, we assessed whether the size distribution could be explained by the non-salivary contaminated instrument source in the respective phantom head control procedure using a two-sided unpaired t-test (comparing the mode widths (log(σ)) and peak positions (DP,C)). The aerosol size distribution provided a robust fingerprint of aerosol emission from a source. 41 patients underwent fifteen different dental procedures. For nine procedures, no aerosol was detected above background. Where aerosol was detected, the percentage of procedure time that aerosol was observed above background ranged from 12.7% for ultrasonic scaling, to 42.9% for 3-in-1 air + water syringe. For ultrasonic scaling, 3-in-1 syringe use and surgical drilling, the aerosol size distribution matched the non-salivary contaminated instrument source, with no unexplained aerosol. High and slow speed drilling produced aerosol from patient procedures with different size distributions to those measured from the phantom head controls (mode widths log(σ)) and peaks (DP,C, p< 0.002) and, therefore, may pose a greater risk of salivary contamination. This study provides evidence for sources of aerosol generation during common dental procedures, enabling more informed evaluation of risk and appropriate mitigation strategies.
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Affiliation(s)
- Tom Dudding
- MRC Integrative Epidemiology Unit, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Department of Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Bristol Dental Hospital and School, University of Bristol, Bristol, United Kingdom
| | - Sadiyah Sheikh
- Bristol Aerosol Research Centre, School of Chemistry, University of Bristol, Bristol, United Kingdom
| | - Florence Gregson
- Bristol Aerosol Research Centre, School of Chemistry, University of Bristol, Bristol, United Kingdom
| | - Jennifer Haworth
- Bristol Dental Hospital and School, University of Bristol, Bristol, United Kingdom
- Royal United Hospital Bath, Combe Park, Bath, United Kingdom
| | - Simon Haworth
- MRC Integrative Epidemiology Unit, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Department of Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Bristol Dental Hospital and School, University of Bristol, Bristol, United Kingdom
| | - Barry G. Main
- Department of Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Bristol Dental Hospital and School, University of Bristol, Bristol, United Kingdom
- Bristol Centre for Surgical Research, Population Health Sciences, Bristol Medical School, Bristol, United Kingdom
| | - Andrew J. Shrimpton
- School of Physiology, Pharmacology & Neuroscience, University of Bristol, Bristol, United Kingdom
| | - Fergus W. Hamilton
- MRC Integrative Epidemiology Unit, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Department of Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Infection Sciences, Southmead Hospital, North Bristol NHS Trust, Bristol, United Kingdom
| | | | - Anthony J. Ireland
- Bristol Dental Hospital and School, University of Bristol, Bristol, United Kingdom
- Royal United Hospital Bath, Combe Park, Bath, United Kingdom
| | - Nick A. Maskell
- Academic Respiratory Unit, North Bristol NHS Trust, Bristol, United Kingdom
| | - Jonathan P. Reid
- Bristol Aerosol Research Centre, School of Chemistry, University of Bristol, Bristol, United Kingdom
| | - Bryan R. Bzdek
- Bristol Aerosol Research Centre, School of Chemistry, University of Bristol, Bristol, United Kingdom
| | - Mark Gormley
- MRC Integrative Epidemiology Unit, Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Department of Population Health Sciences, Bristol Medical School, University of Bristol, Bristol, United Kingdom
- Bristol Dental Hospital and School, University of Bristol, Bristol, United Kingdom
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Leonardi AJ, Mishra AK. A Sanitation Argument for Clean Indoor Air: Meeting a Requisite for Safe Public Spaces. Front Public Health 2022; 10:805780. [PMID: 35237550 PMCID: PMC8883285 DOI: 10.3389/fpubh.2022.805780] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2021] [Accepted: 01/06/2022] [Indexed: 11/13/2022] Open
Affiliation(s)
| | - Asit Kumar Mishra
- MaREI Centre, Ryan Institute & School of Engineering, College of Science and Engineering, National University of Ireland Galway, Galway, Ireland
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Effectiveness of commercial portable air cleaners and a do-it-yourself minimum efficiency reporting value (MERV)-13 filter box fan air cleaner in reducing aerosolized bacteriophage MS2. Infect Control Hosp Epidemiol 2022; 44:663-665. [PMID: 35098916 DOI: 10.1017/ice.2022.5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
In an unventilated room, 2 commercial portable air cleaners with high efficiency particulate air (HEPA) filters and a do-it-yourself box fan air cleaner with minimum efficiency reporting value (MERV)-13 filters significantly reduced aerosolized bacteriophage MS2. Increasing airflow and addition of ultraviolet-C light plus titanium dioxide-generated photocatalytic oxidation enhanced viral clearance.
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Greenhalgh T, Katzourakis A, Wyatt TD, Griffin S. Rapid evidence review to inform safe return to campus in the context of coronavirus disease 2019 (COVID-19). Wellcome Open Res 2021; 6:282. [PMID: 34796281 PMCID: PMC8567688 DOI: 10.12688/wellcomeopenres.17270.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/14/2021] [Indexed: 12/12/2022] Open
Abstract
Background: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is transmitted predominantly through the air in crowded and unventilated indoor spaces among unvaccinated people. Universities and colleges are potential settings for its spread. Methods: An interdisciplinary team from public health, virology, and biology used narrative methods to summarise and synthesise evidence on key control measures, taking account of mode of transmission. Results: Evidence from a wide range of primary studies supports six measures. Vaccinate (aim for > 90% coverage and make it easy to get a jab). Require masks indoors, especially in crowded settings. If everyone wears well-fitting cloth masks, source control will be high, but for maximum self-protection, respirator masks should be worn. Masks should not be removed for speaking or singing. Space people out by physical distancing (but there is no "safe" distance because transmission risk varies with factors such as ventilation, activity levels and crowding), reducing class size (including offering blended learning), and cohorting (students remain in small groups with no cross-mixing). Clean indoor air using engineering controls-ventilation (while monitoring CO 2 levels), inbuilt filtration systems, or portable air cleaners fitted with high efficiency particulate air [HEPA] filters). Test asymptomatic staff and students using lateral flow tests, with tracing and isolating infectious cases when incidence of coronavirus disease 2019 (COVID-19) is high. Support clinically vulnerable people to work remotely. There is no direct evidence to support hand sanitising, fomite controls or temperature-taking. There is evidence that freestanding plastic screens, face visors and electronic air-cleaning systems are ineffective. Conclusions: The above six evidence-based measures should be combined into a multi-faceted strategy to maximise both student safety and the continuation of in-person and online education provision. Staff and students seeking to negotiate a safe working and learning environment should collect data (e.g. CO 2 levels, room occupancy) to inform conversations.
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Affiliation(s)
- Trisha Greenhalgh
- Nuffield Department of Primary Care Health Sciences, University of Oxford, Oxford, OXFORDSHIRE, OX2 6GG, UK
| | - Aris Katzourakis
- Department of Zoology, University of Oxford, Oxford, OXFORDSHIRE, OX1 3SY, UK
| | - Tristram D. Wyatt
- Department of Zoology, University of Oxford, Oxford, OXFORDSHIRE, OX1 3SY, UK
| | - Stephen Griffin
- Leeds Institute of Medical Research, University of Leeds, Leeds, YORKSHIRE, LS9 7TF, UK
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