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Alqarni Z, Rezgui Y, Petri I, Ghoroghi A. Viral infection transmission and indoor air quality: A systematic review. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 923:171308. [PMID: 38432379 DOI: 10.1016/j.scitotenv.2024.171308] [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: 12/14/2023] [Revised: 02/03/2024] [Accepted: 02/25/2024] [Indexed: 03/05/2024]
Abstract
Respiratory disease transmission in indoor environments presents persistent challenges for health authorities, as exemplified by the recent COVID-19 pandemic. This underscores the urgent necessity to investigate the dynamics of viral infection transmission within indoor environments. This systematic review delves into the methodologies of respiratory infection transmission in indoor settings and explores how the quality of indoor air (IAQ) can be controlled to alleviate this risk while considering the imperative of sustainability. Among the 2722 articles reviewed, 178 were retained based on their focus on respiratory viral infection transmission and IAQ. Fifty eight articles delved into SARS-CoV-2 transmission, 21 papers evaluated IAQ in contexts of other pandemics, 53 papers assessed IAQ during the SARS-CoV-2 pandemic, and 46 papers examined control strategies to mitigate infectious transmission. Furthermore, of the 46 papers investigating control strategies, only nine considered energy consumption. These findings highlight clear gaps in current research, such as analyzing indoor air and surface samples for specific indoor environments, oversight of indoor and outdoor parameters (e.g., temperature, relative humidity (RH), and building orientation), neglect of occupancy schedules, and the absence of considerations for energy consumption while enhancing IAQ. This study distinctly identifies the indoor environmental conditions conducive to the thriving of each respiratory virus, offering IAQ trade-offs to mitigate the risk of dominant viruses at any given time. This study argues that future research should involve digital twins in conjunction with machine learning (ML) techniques. This approach aims to enhance IAQ by analyzing the transmission patterns of various respiratory viruses while considering energy consumption.
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Affiliation(s)
- Zahi Alqarni
- School of Engineering, Cardiff University, Cardiff CF24 3AA, UK; School of Computer Science, King Khalid University, Abha 62529, Saudi Arabia.
| | - Yacine Rezgui
- School of Engineering, Cardiff University, Cardiff CF24 3AA, UK
| | - Ioan Petri
- School of Engineering, Cardiff University, Cardiff CF24 3AA, UK
| | - Ali Ghoroghi
- School of Engineering, Cardiff University, Cardiff CF24 3AA, UK
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Chen K. Holistic understanding of ventilation rate in occupational health risk control. Ann N Y Acad Sci 2024; 1531:3-11. [PMID: 38050986 DOI: 10.1111/nyas.15087] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/07/2023]
Abstract
Throughout the history of occupational health risk control, ventilation has been implemented widely as a tried-and-true method to reduce exposure intensity to airborne contaminants. Proper determination of the ventilation rate merits careful consideration when addressing concerns directed toward occupational health and indoor air quality in commercial buildings, albeit this does not translate well among the current engineering and scientific community. This article aims to facilitate a better understanding and proper determination of ventilation rates as a countermeasure for occupational health risk control. To that end, guidance is provided to select the appropriate ventilation rate for nonpandemic versus pandemic scenarios in terms of pertinent regulatory/professional codes and mathematical modeling tools. Limitations and assumptions of the models are summarized to facilitate proper application. Furthermore, the emerging DNA-based aerosol tracing technology, which helps to verify ventilation efficacy, is discussed.
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Affiliation(s)
- Kang Chen
- PetroChina Shanghai Advanced Materials Research Institute, Shanghai, China
- Capitol Technology University, Laurel, Maryland, USA
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Yates TA, Karat AS, Bozzani F, McCreesh N, MacGregor H, Beckwith PG, Govender I, Colvin CJ, Kielmann K, Grant AD. Time to change the way we think about tuberculosis infection prevention and control in health facilities: insights from recent research. ANTIMICROBIAL STEWARDSHIP & HEALTHCARE EPIDEMIOLOGY : ASHE 2023; 3:e117. [PMID: 37502244 PMCID: PMC10369445 DOI: 10.1017/ash.2023.192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 05/25/2023] [Accepted: 05/26/2023] [Indexed: 07/29/2023]
Abstract
In clinical settings where airborne pathogens, such as Mycobacterium tuberculosis, are prevalent, they constitute an important threat to health workers and people accessing healthcare. We report key insights from a 3-year project conducted in primary healthcare clinics in South Africa, alongside other recent tuberculosis infection prevention and control (TB-IPC) research. We discuss the fragmentation of TB-IPC policies and budgets; the characteristics of individuals attending clinics with prevalent pulmonary tuberculosis; clinic congestion and patient flow; clinic design and natural ventilation; and the facility-level determinants of the implementation (or not) of TB-IPC interventions. We present modeling studies that describe the contribution of M. tuberculosis transmission in clinics to the community tuberculosis burden and economic evaluations showing that TB-IPC interventions are highly cost-effective. We argue for a set of changes to TB-IPC, including better coordination of policymaking, clinic decongestion, changes to clinic design and building regulations, and budgeting for enablers to sustain implementation of TB-IPC interventions. Additional research is needed to find the most effective means of improving the implementation of TB-IPC interventions; to develop approaches to screening for prevalent pulmonary tuberculosis that do not rely on symptoms; and to identify groups of patients that can be seen in clinic less frequently.
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Affiliation(s)
- Tom A. Yates
- Division of Infection and Immunity, Faculty of Medicine, University College London, London, UK
| | - Aaron S. Karat
- TB Centre, London School of Hygiene & Tropical Medicine, London, UK
- The Institute for Global Health and Development, Queen Margaret University, Musselburgh, UK
| | | | - Nicky McCreesh
- TB Centre, London School of Hygiene & Tropical Medicine, London, UK
| | - Hayley MacGregor
- The Institute of Development Studies, University of Sussex, Brighton, UK
| | - Peter G. Beckwith
- Department of Medicine, University of Cape Town, Rondebosch, South Africa
| | - Indira Govender
- TB Centre, London School of Hygiene & Tropical Medicine, London, UK
- Africa Health Research Institute, Durban, KwaZulu-Natal, South Africa
| | - Christopher J. Colvin
- Division of Social and Behavioural Sciences, Faculty of Health Sciences, University of Cape Town, Cape Town, South Africa
| | - Karina Kielmann
- The Institute for Global Health and Development, Queen Margaret University, Musselburgh, UK
- Institute of Tropical Medicine, Antwerp, Belgium
| | - Alison D. Grant
- TB Centre, London School of Hygiene & Tropical Medicine, London, UK
- Africa Health Research Institute, Durban, KwaZulu-Natal, South Africa
- School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, DurbanSouth Africa
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Deol AK, Shaikh N, Middelkoop K, Mohlamonyane M, White RG, McCreesh N. Importance of ventilation and occupancy to Mycobacterium tuberculosis transmission rates in congregate settings. BMC Public Health 2022; 22:1772. [PMID: 36123653 PMCID: PMC9483862 DOI: 10.1186/s12889-022-14133-5] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/17/2021] [Accepted: 09/06/2022] [Indexed: 12/02/2022] Open
Abstract
BACKGROUND Ventilation rates are a key determinant of the transmission rate of Mycobacterium tuberculosis and other airborne infections. Targeting infection prevention and control (IPC) interventions at locations where ventilation rates are low and occupancy high could be a highly effective intervention strategy. Despite this, few data are available on ventilation rates and occupancy in congregate locations in high tuberculosis burden settings. METHODS We collected carbon dioxide concentration and occupancy data in congregate locations and public transport on 88 occasions, in Cape Town, South Africa. For each location, we estimated ventilation rates and the relative rate of infection, accounting for ventilation rates and occupancy. RESULTS We show that the estimated potential transmission rate in congregate settings and public transport varies greatly between different settings. Overall, in the community we studied, estimated infection risk was higher in minibus taxis and trains than in salons, bars, and shops. Despite good levels of ventilation, infection risk could be high in the clinic due to high occupancy levels. CONCLUSION Public transport in particular may be promising targets for infection prevention and control interventions in this setting, both to reduce Mtb transmission, but also to reduce the transmission of other airborne pathogens such as measles and SARS-CoV-2.
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Affiliation(s)
- A. K. Deol
- grid.8991.90000 0004 0425 469XDepartment of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - N. Shaikh
- grid.8991.90000 0004 0425 469XDepartment of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - K. Middelkoop
- grid.7836.a0000 0004 1937 1151The Desmond Tutu HIV Centre, Institute of Infectious Disease and Molecular Medicine and Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - M. Mohlamonyane
- grid.7836.a0000 0004 1937 1151The Desmond Tutu HIV Centre, Institute of Infectious Disease and Molecular Medicine and Department of Medicine, University of Cape Town, Cape Town, South Africa
| | - R. G. White
- grid.8991.90000 0004 0425 469XDepartment of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
| | - N. McCreesh
- grid.8991.90000 0004 0425 469XDepartment of Infectious Disease Epidemiology, London School of Hygiene and Tropical Medicine, London, UK
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Beckwith PG, Karat AS, Govender I, Deol AK, McCreesh N, Kielmann K, Baisley K, Grant AD, Yates TA. Direct estimates of absolute ventilation and estimated Mycobacterium tuberculosis transmission risk in clinics in South Africa. PLOS GLOBAL PUBLIC HEALTH 2022; 2:e0000603. [PMID: 36962521 PMCID: PMC10021606 DOI: 10.1371/journal.pgph.0000603] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Accepted: 10/03/2022] [Indexed: 11/07/2022]
Abstract
Healthcare facilities are important sites for the transmission of pathogens spread via bioaerosols, such as Mycobacterium tuberculosis. Natural ventilation can play an important role in reducing this transmission. We aimed to measure rates of natural ventilation in clinics in KwaZulu-Natal and Western Cape provinces, South Africa, then use these measurements to estimate Mycobacterium tuberculosis transmission risk. We measured ventilation in clinic spaces using a tracer-gas release method. In spaces where this was not possible, we estimated ventilation using data on indoor and outdoor carbon dioxide levels. Ventilation was measured i) under usual conditions and ii) with all windows and doors fully open. Under various assumptions about infectiousness and duration of exposure, measured absolute ventilation rates were related to risk of Mycobacterium tuberculosis transmission using the Wells-Riley Equation. In 2019, we obtained ventilation measurements in 33 clinical spaces in 10 clinics: 13 consultation rooms, 16 waiting areas and 4 other clinical spaces. Under usual conditions, the absolute ventilation rate was much higher in waiting rooms (median 1769 m3/hr, range 338-4815 m3/hr) than in consultation rooms (median 197 m3/hr, range 0-1451 m3/hr). When compared with usual conditions, fully opening existing doors and windows resulted in a median two-fold increase in ventilation. Using standard assumptions about infectiousness, we estimated that a health worker would have a 24.8% annual risk of becoming infected with Mycobacterium tuberculosis, and that a patient would have an 0.1% risk of becoming infected per visit. Opening existing doors and windows and rearranging patient pathways to preferentially use better ventilated clinic spaces result in important reductions in Mycobacterium tuberculosis transmission risk. However, unless combined with other tuberculosis infection prevention and control interventions, these changes are insufficient to reduce risk to health workers, and other highly exposed individuals, to acceptable levels.
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Affiliation(s)
- Peter G Beckwith
- Department of Medicine, University of Cape Town, Cape Town, South Africa
- TB Centre, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Aaron S Karat
- Department of Medicine, University of Cape Town, Cape Town, South Africa
- The Institute for Global Health and Development, Queen Margaret University, Edinburgh, United Kingdom
| | - Indira Govender
- TB Centre, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Africa Health Research Institute, School of Laboratory Medicine & Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Arminder K Deol
- TB Centre, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Nicky McCreesh
- TB Centre, London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Karina Kielmann
- The Institute for Global Health and Development, Queen Margaret University, Edinburgh, United Kingdom
- Institute of Tropical Medicine, Antwerp, Belgium
| | - Kathy Baisley
- Department of Infectious Disease Epidemiology, The London School of Hygiene & Tropical Medicine, London, United Kingdom
| | - Alison D Grant
- TB Centre, London School of Hygiene & Tropical Medicine, London, United Kingdom
- Africa Health Research Institute, School of Laboratory Medicine & Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
- School of Laboratory Medicine and Medical Sciences, College of Health Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Tom A Yates
- Division of Infection and Immunity, Faculty of Medicine, University College London, London, United Kingdom
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McCreesh N, Karat AS, Baisley K, Diaconu K, Bozzani F, Govender I, Beckwith P, Yates TA, Deol AK, Houben RMGJ, Kielmann K, White RG, Grant AD. Modelling the effect of infection prevention and control measures on rate of Mycobacterium tuberculosis transmission to clinic attendees in primary health clinics in South Africa. BMJ Glob Health 2021; 6:e007124. [PMID: 34697087 PMCID: PMC8547367 DOI: 10.1136/bmjgh-2021-007124] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2021] [Accepted: 10/08/2021] [Indexed: 12/22/2022] Open
Abstract
BACKGROUND Elevated rates of tuberculosis in healthcare workers demonstrate the high rate of Mycobacterium tuberculosis (Mtb) transmission in health facilities in high-burden settings. In the context of a project taking a whole systems approach to tuberculosis infection prevention and control (IPC), we aimed to evaluate the potential impact of conventional and novel IPC measures on Mtb transmission to patients and other clinic attendees. METHODS An individual-based model of patient movements through clinics, ventilation in waiting areas, and Mtb transmission was developed, and parameterised using empirical data from eight clinics in two provinces in South Africa. Seven interventions-codeveloped with health professionals and policy-makers-were simulated: (1) queue management systems with outdoor waiting areas, (2) ultraviolet germicidal irradiation (UVGI) systems, (3) appointment systems, (4) opening windows and doors, (5) surgical mask wearing by clinic attendees, (6) simple clinic retrofits and (7) increased coverage of long antiretroviral therapy prescriptions and community medicine collection points through the Central Chronic Medicine Dispensing and Distribution (CCMDD) service. RESULTS In the model, (1) outdoor waiting areas reduced the transmission to clinic attendees by 83% (IQR 76%-88%), (2) UVGI by 77% (IQR 64%-85%), (3) appointment systems by 62% (IQR 45%-75%), (4) opening windows and doors by 55% (IQR 25%-72%), (5) masks by 47% (IQR 42%-50%), (6) clinic retrofits by 45% (IQR 16%-64%) and (7) increasing the coverage of CCMDD by 22% (IQR 12%-32%). CONCLUSIONS The majority of the interventions achieved median reductions in the rate of transmission to clinic attendees of at least 45%, meaning that a range of highly effective intervention options are available, that can be tailored to the local context. Measures that are not traditionally considered to be IPC interventions, such as appointment systems, may be as effective as more traditional IPC measures, such as mask wearing.
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Affiliation(s)
- Nicky McCreesh
- TB Centre, London School of Hygiene and Tropical Medicine, London, UK
| | - Aaron S Karat
- TB Centre, London School of Hygiene and Tropical Medicine, London, UK
- Institute for Global Health & Development, Queen Margaret University Edinburgh, Musselburgh, UK
| | - Kathy Baisley
- TB Centre, London School of Hygiene and Tropical Medicine, London, UK
| | - Karin Diaconu
- Institute for Global Health & Development, Queen Margaret University Edinburgh, Musselburgh, UK
| | - Fiammetta Bozzani
- TB Centre, London School of Hygiene and Tropical Medicine, London, UK
| | - Indira Govender
- TB Centre, London School of Hygiene and Tropical Medicine, London, UK
- Africa Health Research Institute, Durban, KwaZulu-Natal, South Africa
| | - Peter Beckwith
- Department of Medicine, University of Cape Town, Rondebosch, South Africa
| | - Tom A Yates
- Department of Infectious Disease, Faculty of Medicine, Imperial College London, London, UK
| | - Arminder K Deol
- TB Centre, London School of Hygiene and Tropical Medicine, London, UK
| | - Rein M G J Houben
- TB Centre, London School of Hygiene and Tropical Medicine, London, UK
| | - Karina Kielmann
- Institute for Global Health & Development, Queen Margaret University Edinburgh, Musselburgh, UK
| | - Richard G White
- TB Centre, London School of Hygiene and Tropical Medicine, London, UK
| | - Alison D Grant
- TB Centre, London School of Hygiene and Tropical Medicine, London, UK
- Africa Health Research Institute, Durban, KwaZulu-Natal, South Africa
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