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Moseley B, Archer J, Orton CM, Symons HE, Watson NA, Saccente-Kennedy B, Philip KEJ, Hull JH, Costello D, Calder JD, Shah PL, Bzdek BR, Reid JP. Relationship between Exhaled Aerosol and Carbon Dioxide Emission Across Respiratory Activities. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58. [PMID: 39138123 PMCID: PMC11360368 DOI: 10.1021/acs.est.4c01717] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/20/2024] [Revised: 07/31/2024] [Accepted: 08/01/2024] [Indexed: 08/15/2024]
Abstract
Respiratory particles produced during vocalized and nonvocalized activities such as breathing, speaking, and singing serve as a major route for respiratory pathogen transmission. This work reports concomitant measurements of exhaled carbon dioxide volume (VCO2) and minute ventilation (VE), along with exhaled respiratory particles during breathing, exercising, speaking, and singing. Exhaled CO2 and VE measured across healthy adult participants follow a similar trend to particle number concentration during the nonvocalized exercise activities (breathing at rest, vigorous exercise, and very vigorous exercise). Exhaled CO2 is strongly correlated with mean particle number (r = 0.81) and mass (r = 0.84) emission rates for the nonvocalized exercise activities. However, exhaled CO2 is poorly correlated with mean particle number (r = 0.34) and mass (r = 0.12) emission rates during activities requiring vocalization. These results demonstrate that in most real-world environments vocalization loudness is the main factor controlling respiratory particle emission and exhaled CO2 is a poor surrogate measure for estimating particle emission during vocalization. Although measurements of indoor CO2 concentrations provide valuable information about room ventilation, such measurements are poor indicators of respiratory particle concentrations and may significantly underestimate respiratory particle concentrations and disease transmission risk.
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Affiliation(s)
- Benjamin Moseley
- Department
of Respiratory Medicine, Royal Brompton
Hospital, London SW3 6NP, U.K.
| | - Justice Archer
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, U.K.
| | - Christopher M. Orton
- Department
of Respiratory Medicine, Royal Brompton
Hospital, London SW3 6NP, U.K.
- Department
of Respiratory Medicine, Chelsea & Westminster
Hospital, London SW10 9NH, U.K.
- National
Heart and Lung Institute, Guy Scadding Building,
Imperial College London, London SW3 6LY, U.K.
| | - Henry E. Symons
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, U.K.
| | - Natalie A. Watson
- Department
of Ear, Nose and Throat Surgery, Guy’s
& St. Thomas NHS Foundation Trust, London SE1 9RT, U.K.
| | - Brian Saccente-Kennedy
- Department
of Speech and Language Therapy (ENT), Royal National Ear, Nose and
Throat and Eastman Dental Hospitals, University
College London Hospitals NHS Foundation Trust, London WC1E 6DG, U.K.
| | - Keir E. J. Philip
- Department
of Respiratory Medicine, Royal Brompton
Hospital, London SW3 6NP, U.K.
- National
Heart and Lung Institute, Guy Scadding Building,
Imperial College London, London SW3 6LY, U.K.
| | - James H. Hull
- Department
of Respiratory Medicine, Royal Brompton
Hospital, London SW3 6NP, U.K.
- Institute
of Sport, Exercise and Health (ISEH), UCL, London W1T 7HA, U.K.
| | - Declan Costello
- Ear,
Nose and Throat Department, Wexham Park
Hospital, Slough SL2 4HL, U.K.
| | - James D. Calder
- Department
of Bioengineering, Imperial College London, London SW7 2AZ, U.K.
- Fortius Clinic, London W1H 6EQ, U.K.
| | - Pallav L. Shah
- Department
of Respiratory Medicine, Royal Brompton
Hospital, London SW3 6NP, U.K.
- Department
of Respiratory Medicine, Chelsea & Westminster
Hospital, London SW10 9NH, U.K.
- National
Heart and Lung Institute, Guy Scadding Building,
Imperial College London, London SW3 6LY, U.K.
| | - Bryan R. Bzdek
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, U.K.
| | - Jonathan P. Reid
- School
of Chemistry, University of Bristol, Bristol BS8 1TS, U.K.
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2
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Ruuskanen O, Dollner H, Luoto R, Valtonen M, Heinonen OJ, Waris M. Contraction of Respiratory Viral Infection During air Travel: An Under-Recognized Health Risk for Athletes. SPORTS MEDICINE - OPEN 2024; 10:60. [PMID: 38776030 PMCID: PMC11111432 DOI: 10.1186/s40798-024-00725-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 05/09/2024] [Indexed: 05/25/2024]
Abstract
Air travel has an important role in the spread of viral acute respiratory infections (ARIs). Aircraft offer an ideal setting for the transmission of ARI because of a closed environment, crowded conditions, and close-contact setting. Numerous studies have shown that influenza and COVID-19 spread readily in an aircraft with one virus-positive symptomatic or asymptomatic index case. The numbers of secondary cases differ markedly in different studies most probably because of the wide variation of the infectiousness of the infector as well as the susceptibility of the infectees. The primary risk factor is sitting within two rows of an infectious passenger. Elite athletes travel frequently and are thus prone to contracting an ARI during travel. It is anecdotally known in the sport and exercise medicine community that athletes often contract ARI during air travel. The degree to which athletes are infected in an aircraft by respiratory viruses is unclear. Two recent studies suggest that 8% of Team Finland members traveling to major winter sports events contracted the common cold most probably during air travel. Further prospective clinical studies with viral diagnostics are needed to understand the transmission dynamics and to develop effective and socially acceptable preventive measures during air travel.
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Affiliation(s)
- Olli Ruuskanen
- Department of Paediatrics and Adolescent Medicine, Turku University Hospital and University of Turku, PL 52, 20521, Turku, Finland
| | - Henrik Dollner
- Department of Clinical and Molecular Medicine, Children's Clinic, St. Olavs University Hospital, Norwegian University of Science and Technology, Trondheim, Norway
| | - Raakel Luoto
- Department of Paediatrics and Adolescent Medicine, Turku University Hospital and University of Turku, PL 52, 20521, Turku, Finland
| | | | - Olli J Heinonen
- Paavo Nurmi Centre and Unit for Health and Physical Activity, University of Turku, Turku, Finland
| | - Matti Waris
- Institute of Biomedicine, University of Turku and Department of Clinical Virology, Turku University Hospital, Kiinamyllynkatu 10, 20520, Turku, Finland.
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3
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Luo Q, Liu W, Liao J, Gu Z, Fan X, Luo Z, Zhang X, Hang J, Ou C. COVID-19 transmission and control in land public transport: A literature review. FUNDAMENTAL RESEARCH 2024; 4:417-429. [PMID: 38933205 PMCID: PMC11197583 DOI: 10.1016/j.fmre.2023.10.013] [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: 09/30/2022] [Revised: 10/18/2023] [Accepted: 10/20/2023] [Indexed: 06/28/2024] Open
Abstract
Land public transport is an important link within and between cities, and how to control the transmission of COVID-19 in land public transport is a critical issue in our daily lives. However, there are still many inconsistent opinions and views about the spread of SARS-CoV-2 in land public transport, which limits our ability to implement effective interventions. The purpose of this review is to overview the literature on transmission characteristics and routes of the epidemic in land public transport, as well as to investigate factors affecting its spread and provide feasible measures to mitigate the infection risk of passengers. We obtained 898 papers by searching the Web of Science, Pubmed, and WHO global COVID database by keywords, and finally selected 45 papers that can address the purpose of this review. Land public transport is a high outbreak area for COVID-19 due to characteristics like crowding, inadequate ventilation, long exposure time, and environmental closure. Different from surface touch transmission and drop spray transmission, aerosol inhalation transmission can occur not only in short distances but also in long distances. Insufficient ventilation is the most important factor influencing long-distance aerosol transmission. Other transmission factors (e.g., interpersonal distance, relative orientation, and ambient conditions) should be noticed as well, which have been summarized in this paper. To address various influencing factors, it is essential to suggest practical and efficient preventive measures. Among these, increased ventilation, particularly the fresh air (i.e., natural ventilation), has proven to effectively reduce indoor infection risk. Many preventive measures are also effective, such as enlarging social distance, avoiding face-to-face orientation, setting up physical partitions, disinfection, avoiding talking, and so on. As research on the epidemic has intensified, people have broken down many perceived barriers, but more comprehensive studies on monitoring systems and prevention measures in land public transport are still needed.
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Affiliation(s)
- Qiqi Luo
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai 519082, China
- Key Laboratory of Urban Meteorology, China Meteorological Administration, Beijing 100089, China
- China Meteorological Administration Xiong'an Atmospheric Boundary Layer Key Laboratory, Xiong'an 070001, China
- Key Laboratory of Tropical Atmosphere-Ocean System (Sun Yat-sen University), Ministry of Education, Zhuhai 519000, China
| | - Wenbing Liu
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai 519082, China
| | - Jiayuan Liao
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai 519082, China
| | - Zhongli Gu
- Guangdong Fans-tech Agro Co., Ltd, Yunfu 527300, China
| | - Xiaodan Fan
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai 519082, China
| | - Zhiwen Luo
- Welsh School of Architecture, Cardiff University, Cardiff CF10 3XQ, United Kingdom
| | - Xuelin Zhang
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai 519082, China
| | - Jian Hang
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai 519082, China
- Key Laboratory of Urban Meteorology, China Meteorological Administration, Beijing 100089, China
- China Meteorological Administration Xiong'an Atmospheric Boundary Layer Key Laboratory, Xiong'an 070001, China
- Key Laboratory of Tropical Atmosphere-Ocean System (Sun Yat-sen University), Ministry of Education, Zhuhai 519000, China
| | - Cuiyun Ou
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory, Zhuhai 519082, China
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Thampi N, Guzman-Cottrill J, Bartlett AH, Berg W, Cantey JB, Kitt E, Ravin K, Zangwill KM, Elward A. SHEA NICU white paper series: Practical approaches for the prevention of viral respiratory infections. Infect Control Hosp Epidemiol 2024; 45:267-276. [PMID: 37877172 DOI: 10.1017/ice.2023.120] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2023]
Abstract
This white paper provides clinicians and hospital leaders with practical guidance on the prevention and control of viral respiratory infections in the neonatal intensive care unit (NICU). This document serves as a companion to Centers for Disease Control and Prevention Healthcare Infection Control Practices Advisory Committee (HICPAC)'s "Prophylaxis and Screening for Prevention of Viral Respiratory Infections in Neonatal Intensive Care Unit Patients: A Systematic Review." It provides practical, expert opinion and/or evidence-based answers to frequently asked questions about viral respiratory detection and prevention in the NICU. It was developed by a writing panel of pediatric and pathogen-specific experts who collaborated with members of the HICPAC systematic review writing panel and the SHEA Pediatric Leadership Council to identify questions that should be addressed. The document has been endorsed by SHEA, the American Hospital Association (AHA), The Joint Commission, the Pediatric Infectious Diseases Society (PIDS), the Association for Professionals in Infection Control and Epidemiology (APIC), the Infectious Diseases Society of America (IDSA), and the National Association of Neonatal Nurses (NANN).
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Affiliation(s)
- Nisha Thampi
- Children's Hospital of Eastern Ontario, Ottawa, Ontario, Canada
| | | | - Allison H Bartlett
- University of Chicago and Comer Children's Hospital, Chicago, Illinois, USA
| | - Wendy Berg
- Children's Minnesota, St. Paul, Minnesota, USA
| | - Joseph B Cantey
- The University of Texas Health Science Center, San Antonio, Texas, USA
| | - Eimear Kitt
- Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, USA
| | - Karen Ravin
- Nemours Children's Health, Wilmington, Delaware, USA
| | | | - Alexis Elward
- Washington University School of Medicine, St. Louis, Missouri, USA
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5
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Ijaz MK, Sattar SA, Nims RW, Boone SA, McKinney J, Gerba CP. Environmental dissemination of respiratory viruses: dynamic interdependencies of respiratory droplets, aerosols, aerial particulates, environmental surfaces, and contribution of viral re-aerosolization. PeerJ 2023; 11:e16420. [PMID: 38025703 PMCID: PMC10680453 DOI: 10.7717/peerj.16420] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Accepted: 10/17/2023] [Indexed: 12/01/2023] Open
Abstract
During the recent pandemic of COVID-19 (SARS-CoV-2), influential public health agencies such as the World Health Organization (WHO) and the U.S. Centers for Disease Control and Prevention (CDC) have favored the view that SARS CoV-2 spreads predominantly via droplets. Many experts in aerobiology have openly opposed that stance, forcing a vigorous debate on the topic. In this review, we discuss the various proposed modes of viral transmission, stressing the interdependencies between droplet, aerosol, and fomite spread. Relative humidity and temperature prevailing determine the rates at which respiratory aerosols and droplets emitted from an expiratory event (sneezing, coughing, etc.) evaporate to form smaller droplets or aerosols, or experience hygroscopic growth. Gravitational settling of droplets may result in contamination of environmental surfaces (fomites). Depending upon human, animal and mechanical activities in the occupied space indoors, viruses deposited on environmental surfaces may be re-aerosolized (re-suspended) to contribute to aerosols, and can be conveyed on aerial particulate matter such as dust and allergens. The transmission of respiratory viruses may then best be viewed as resulting from dynamic virus spread from infected individuals to susceptible individuals by various physical states of active respiratory emissions, instead of the current paradigm that emphasizes separate dissemination by respiratory droplets, aerosols or by contaminated fomites. To achieve the optimum outcome in terms of risk mitigation and infection prevention and control (IPAC) during seasonal infection peaks, outbreaks, and pandemics, this holistic view emphasizes the importance of dealing with all interdependent transmission modalities, rather than focusing on one modality.
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Affiliation(s)
- M. Khalid Ijaz
- Global Research & Development for Lysol and Dettol, Reckitt Benckiser LLC, Montvale, NJ, United States of America
| | - Syed A. Sattar
- Department of Biochemistry, Microbiology & Immunology, Faculty of Medicine, University of Ottawa, Ottawa, Ontario, Canada
| | | | - Stephanie A. Boone
- Water & Energy Sustainable Technology Center, University of Arizona, Tucson, AZ, United States of America
| | - Julie McKinney
- Global Research & Development for Lysol and Dettol, Reckitt Benckiser LLC, Montvale, NJ, United States of America
| | - Charles P. Gerba
- Water & Energy Sustainable Technology Center, University of Arizona, Tucson, AZ, United States of America
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6
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Hanna F, Alameddine I, Zaraket H, Alkalamouni H, El-Fadel M. Airborne influenza virus shedding by patients in health care units: Removal mechanisms affecting virus transmission. PLoS One 2023; 18:e0290124. [PMID: 37878553 PMCID: PMC10599543 DOI: 10.1371/journal.pone.0290124] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Accepted: 08/01/2023] [Indexed: 10/27/2023] Open
Abstract
In this study, we characterize the distribution of airborne viruses (influenza A/B) in hospital rooms of patients with confirmed infections. Concurrently, we monitored fine particulate matter (PM2.5 & PM10) and several physical parameters including the room air exchange rate, temperature, and relative humidity to identify corresponding correlations with virus transport and removal determinants. The results continue to raise concerns about indoor air quality (IAQ) in healthcare facilities and the potential exposure of patients, staff and visitors to aerosolized viruses as well as elevated indoor PM levels caused by outdoor sources and/or re-suspension of settled particles by indoor activities. The influenza A virus was detected in 42% of 33 monitored rooms, with viruses detectible up to 1.5 m away from the infected patient. Active coughing was a statistically significant variable that contributed to a higher positive rate of virus detection in the collected air samples. Viral load across patient rooms ranged between 222 and 5,760 copies/m3, with a mean of 820 copies/m3. Measured PM2.5 and PM10 levels exceeded IAQ daily exposure guidelines in most monitored rooms. Statistical and numerical analyses showed that dispersion was the dominant viral removal pathway followed by settling. Changes in the relative humidity and the room's temperature were had a significant impact on the viral load removal. In closure, we highlight the need for an integrated approach to control determinants of IAQ in patients' rooms.
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Affiliation(s)
- Francis Hanna
- Department of Civil Infrastructure & Environmental Engineering, College of Engineering, Khalifa University, United Arab Emirates
- Department of Civil & Environmental Engineering, Faculty of Engineering & Architecture, American University of Beirut, Lebanon
| | - Ibrahim Alameddine
- Department of Civil & Environmental Engineering, Faculty of Engineering & Architecture, American University of Beirut, Lebanon
| | - Hassan Zaraket
- Department of Experimental Pathology, Immunology & Microbiology, Faculty of Medicine, American University of Beirut, Lebanon
| | - Habib Alkalamouni
- Department of Experimental Pathology, Immunology & Microbiology, Faculty of Medicine, American University of Beirut, Lebanon
| | - Mutasem El-Fadel
- Department of Civil Infrastructure & Environmental Engineering, College of Engineering, Khalifa University, United Arab Emirates
- Department of Civil & Environmental Engineering, Faculty of Engineering & Architecture, American University of Beirut, Lebanon
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7
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Chen Y, Beattie H, Simpson A, Nicholls G, Sandys V, Keen C, Curran AD. A COVID-19 Outbreak in a Large Meat-Processing Plant in England: Transmission Risk Factors and Controls. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2023; 20:6806. [PMID: 37835076 PMCID: PMC10572747 DOI: 10.3390/ijerph20196806] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/11/2023] [Accepted: 09/19/2023] [Indexed: 10/15/2023]
Abstract
The meat-processing industry had frequent COVID-19 outbreaks reported worldwide. In May 2021, a large meat-processing plant in the UK had an outbreak affecting 4.1% (63/1541) of workers. A rapid on-site investigation was conducted to understand the virus transmission risk factors and control measures. This included observational assessments of work activities, control measures, real-time environmental measurements and surface microbial sampling. The production night-shift attack rate (11.6%, 44/380) was nearly five times higher than the production day-shift (2.4%, 9/380). Shared work transport was provided to 150 staff per dayshift and 104 per nightshift. Production areas were noisy (≥80 dB(A)) and physical distancing was difficult to maintain. Face visors were mandatory, additional face coverings were required for some activities but not always worn. The refrigeration system continuously recirculated chilled air. In some areas, the mean temperature was as low as 4.5 °C and mean relative humidity (RH) was as high as 96%. The adequacy of ventilation in the production areas could not be assessed reliably using CO2, due to the use of CO2 in the packaging process. While there were challenges in the production areas, the observed COVID-19 control measures were generally implemented well in the non-production areas. Sixty surface samples from all areas were tested for SARS-CoV-2 RNA and 11.7% were positive. Multi-layered measures, informed by a workplace specific risk assessment, are required to prevent and control workplace outbreaks of COVID-19 or other similar respiratory infectious diseases.
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Affiliation(s)
- Yiqun Chen
- Science Division, Health and Safety Executive, Buxton SK17 9JN, UK
| | - Helen Beattie
- Science Division, Health and Safety Executive, Buxton SK17 9JN, UK
| | - Andrew Simpson
- Science Division, Health and Safety Executive, Buxton SK17 9JN, UK
| | - Gillian Nicholls
- Science Division, Health and Safety Executive, Buxton SK17 9JN, UK
| | - Vince Sandys
- Science Division, Health and Safety Executive, Buxton SK17 9JN, UK
| | - Chris Keen
- Science Division, Health and Safety Executive, Buxton SK17 9JN, UK
| | - Andrew D Curran
- Science Division, Health and Safety Executive, Buxton SK17 9JN, UK
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8
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Bassanello M, Geppini R, Bonsembiante E, Coli U, Farencena A, D’Aquino M, Gambaro A, Buja A, Baldovin T. Risk of SARS-CoV-2 transmission in the close contacts in a small rural area in the Veneto Region (NE-Italy): past evidence for future scenarios. Front Public Health 2023; 11:1223109. [PMID: 37732097 PMCID: PMC10507707 DOI: 10.3389/fpubh.2023.1223109] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2023] [Accepted: 08/14/2023] [Indexed: 09/22/2023] Open
Abstract
Background During the first pandemic phase of COVID-19, an epidemiological study, named First survey, was conducted on the population of a small rural area in northern Italy. In spring 2020, the results showed how a prolonged lockdown slowed down the spread of the virus. Methods After contacting positive First Survey subjects and their families, those who decided to join voluntarily underwent a blood test to assess the presence of qualitative lgG about 2 months after the previous one. This was to determine if IgG persisted in individuals who tested positive in the First Survey as well as to assess the antibody status of their close family members, to determine if they were unintentionally infected. Results Based on serological analysis, 35.1% of the samples contained blood IgG. In subjects who tested positive during the First Survey, 62.5% remained IgG positive more than 2 months later. Among family members who were exposed to a positive relative, 23.7% were infected. Linear regression analysis showed that the presence of an infected person within a household resulted in the infection spreading to the others, but not excessively. Induced isolation extinguished the infection regardless of the extent of the contagion (intra-family or extra-family). Micro-outbreaks of SARS-Cov-2 infection which arose in the same household from extra-familial infections played a decisive role on the statistical significance of IgG-positive subjects (p < 0.001). Discussion The study reveal 52.6% of the IgG-positive subjects in the Second Survey came from the First Survey and 47.4% were family members previously in contact with positive subjects. Data suggest that there have been undiagnosed patients feeding the spread of the virus since the beginning of the pandemic. In conclusion, for future pandemics, it will be necessary: i) to ensure the rapid isolation of symptomatic patients and the early identification of their close contacts, ii) to carry out the maximum number of tests in the shortest possible time, both on symptomatic and asymptomatic subjects, and iii) to implement information campaigns to make people aware of their risks, and implement clear, non-conflicting communication.
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Affiliation(s)
- Marco Bassanello
- Emergency and Health Department, Monastier di Treviso Hospital, Treviso, Italy
- Hygiene and Public Health Unit, Department of Cardiac, Thoracic and Vascular Sciences, School of Medicine and Surgery, University of Padua, Padua, Italy
| | - Ruggero Geppini
- Hygiene and Public Health Unit, Department of Cardiac, Thoracic and Vascular Sciences, School of Medicine and Surgery, University of Padua, Padua, Italy
| | | | - Ugo Coli
- Health Department, Monastier di Treviso Hospital, Treviso, Italy
| | - Aldo Farencena
- Laboratory and Microbiology Monastier di Treviso Hospital, Treviso, Italy
| | | | - Andrea Gambaro
- Department of Environmental Sciences, Informatics and Statistics (DAIS), Ca’ Foscari University of Venice, Venice, Italy
| | - Alessandra Buja
- Hygiene and Public Health Unit, Department of Cardiac, Thoracic and Vascular Sciences, School of Medicine and Surgery, University of Padua, Padua, Italy
| | - Tatjana Baldovin
- Hygiene and Public Health Unit, Department of Cardiac, Thoracic and Vascular Sciences, School of Medicine and Surgery, University of Padua, Padua, Italy
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9
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Feng Y, Zhang Y, Ding X, Fan Y, Ge J. Multi-scale risk assessment and mitigations comparison for COVID-19 in urban public transport: A combined field measurement and modeling approach. BUILDING AND ENVIRONMENT 2023; 242:110489. [PMID: 37333517 PMCID: PMC10236904 DOI: 10.1016/j.buildenv.2023.110489] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Revised: 05/31/2023] [Accepted: 06/02/2023] [Indexed: 06/20/2023]
Abstract
The outbreak of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic has caused an unparalleled disruption to daily life. Given that COVID-19 primarily spreads in densely populated indoor areas, urban public transport (UPT) systems pose significant risks. This study presents an analysis of the air change rate in buses, subways, and high speed trains based on measured CO2 concentrations and passenger behaviors. The resulting values were used as inputs for an infection risk assessment model, which was used to quantitatively evaluate the effects of various factors, including ventilation rates, respiratory activities, and viral variants, on the infection risk. The findings demonstrate that ventilation has a negligible impact on reducing average risks (less than 10.0%) for short-range scales, but can result in a reduction of average risks by 32.1%-57.4% for room scales. When all passengers wear masks, the average risk reduction ranges from 4.5-folds to 7.5-folds. Based on our analysis, the average total reproduction numbers (R) of subways are 1.4-folds higher than buses, and 2-folds higher than high speed trains. Additionally, it is important to note that the Omicron variant may result in a much higher R value, estimated to be approximately 4.9-folds higher than the Delta variant. To reduce disease transmission, it is important to keep the R value below 1. Thus, two indices have been proposed: time-scale based exposure thresholds and spatial-scale based upper limit warnings. Mask wearing provides the greatest protection against infection in the face of long exposure duration to the omicron epidemic.
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Affiliation(s)
- Yinshuai Feng
- College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, China
- Center for Balance Architecture, Zhejiang University, Hangzhou, China
- International Research Center for Green Building and Low-Carbon City, International Campus, Zhejiang University, Haining, China
| | - Yan Zhang
- College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, China
- International Research Center for Green Building and Low-Carbon City, International Campus, Zhejiang University, Haining, China
| | - Xiaotian Ding
- College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, China
- International Research Center for Green Building and Low-Carbon City, International Campus, Zhejiang University, Haining, China
| | - Yifan Fan
- College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, China
- Center for Balance Architecture, Zhejiang University, Hangzhou, China
- International Research Center for Green Building and Low-Carbon City, International Campus, Zhejiang University, Haining, China
| | - Jian Ge
- College of Civil Engineering and Architecture, Zhejiang University, Hangzhou, China
- International Research Center for Green Building and Low-Carbon City, International Campus, Zhejiang University, Haining, China
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10
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Gruode J, Martinkenas A, Kurmis M, Drungilas D, Lukosius Z, Tadzijevas A, Didziokas R, Jankunas V, Sapalas D. RT-qPCR-Based Assessment of the Efficacy of 222 nm UVC Irradiation in Reducing SARS-CoV-2 Surface Contamination. SENSORS (BASEL, SWITZERLAND) 2023; 23:6129. [PMID: 37447977 DOI: 10.3390/s23136129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 06/28/2023] [Accepted: 06/29/2023] [Indexed: 07/15/2023]
Abstract
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), has emerged as a serious threat to human health worldwide. The effective disinfection of surfaces contaminated with SARS-CoV-2 may help prevent its spread. The aim of this study is to determine the duration required for viral RNA elimination by 222 nm far ultraviolet light using RT-qPCR as a tool. This study investigated the effect of 222 nm UVC irradiation on SARS-CoV-2 RNA in an in vitro experiment. The results showed that the copy number of SARS-CoV-2 RNA did not change even after 300 s of 222 nm UVC irradiation at 0.1 mW/cm2, but extending the exposure to more than 600 s reduced the number of copies of SARS-CoV-2 virus significantly. However, to fully validate the results and enhance the robustness of the findings, it is crucial to increase the number of samples analyzed in future experiments.
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Affiliation(s)
- Jurate Gruode
- Marine Research Institute, Klaipeda University, H. Manto Street 84, LT-92294 Klaipeda, Lithuania
| | - Arvydas Martinkenas
- Marine Research Institute, Klaipeda University, H. Manto Street 84, LT-92294 Klaipeda, Lithuania
| | - Mindaugas Kurmis
- Marine Research Institute, Klaipeda University, H. Manto Street 84, LT-92294 Klaipeda, Lithuania
| | - Darius Drungilas
- Marine Research Institute, Klaipeda University, H. Manto Street 84, LT-92294 Klaipeda, Lithuania
| | - Zydrunas Lukosius
- Marine Research Institute, Klaipeda University, H. Manto Street 84, LT-92294 Klaipeda, Lithuania
| | - Arturas Tadzijevas
- Marine Research Institute, Klaipeda University, H. Manto Street 84, LT-92294 Klaipeda, Lithuania
| | - Rimantas Didziokas
- Marine Research Institute, Klaipeda University, H. Manto Street 84, LT-92294 Klaipeda, Lithuania
| | - Valdas Jankunas
- Marine Research Institute, Klaipeda University, H. Manto Street 84, LT-92294 Klaipeda, Lithuania
| | - Deivydas Sapalas
- Marine Research Institute, Klaipeda University, H. Manto Street 84, LT-92294 Klaipeda, Lithuania
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11
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Moschovis PP, Lombay J, Rooney J, Schenkel SR, Singh D, Rezaei SJ, Salo N, Gong A, Yonker LM, Shah J, Hayden D, Hibberd PL, Demokritou P, Kinane TB. The effect of activity and face masks on exhaled particles in children. Pediatr Investig 2023; 7:75-85. [PMID: 37324601 PMCID: PMC10262878 DOI: 10.1002/ped4.12376] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 01/29/2023] [Indexed: 06/17/2023] Open
Abstract
Importance Despite the high burden of respiratory infections among children, the production of exhaled particles during common activities and the efficacy of face masks in children have not been sufficiently studied. Objective To determine the effect of type of activity and mask usage on exhaled particle production in children. Methods Healthy children were asked to perform activities that ranged in intensity (breathing quietly, speaking, singing, coughing, and sneezing) while wearing no mask, a cloth mask, or a surgical mask. The concentration and size of exhaled particles were assessed during each activity. Results Twenty-three children were enrolled in the study. Average exhaled particle concentration increased by intensity of activity, with the lowest particle concentration during tidal breathing (1.285 particles/cm3 [95% CI 0.943, 1.627]) and highest particle concentration during sneezing (5.183 particles/cm3 [95% CI 1.911, 8.455]). High-intensity activities were associated with an increase primarily in the respirable size (≤ 5 µm) particle fraction. Surgical and cloth masks were associated with lower average particle concentration compared to no mask (P = 0.026 for sneezing). Surgical masks outperformed cloth masks across all activities, especially within the respirable size fraction. In a multivariable linear regression model, we observed significant effect modification of activity by age and by mask type. Interpretation Similar to adults, children produce exhaled particles that vary in size and concentration across a range of activities. Production of respirable size fraction particles (≤ 5 µm), the dominant mode of transmission of many respiratory viruses, increases significantly with coughing and sneezing and is most effectively reduced by wearing surgical face masks.
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Affiliation(s)
- Peter P. Moschovis
- Department of PediatricsMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | - Jesiel Lombay
- Department of PediatricsMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | - Jennifer Rooney
- Department of PediatricsMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | - Sara R. Schenkel
- Department of PediatricsMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | - Dilpreet Singh
- Department of Environmental HealthHarvard T. H. Chan School of Public HealthBostonMassachusettsUSA
- Department of Mechanical and Aerospace EngineeringRutgers University School of Public HealthNew BrunswickNew JerseyUSA
| | - Shawheen J. Rezaei
- Department of PediatricsMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | - Nora Salo
- Department of PediatricsMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | - Amanda Gong
- David Geffen School of Medicinethe University of California Los AngelesLos AngelesCaliforniaUSA
| | - Lael M. Yonker
- Department of PediatricsMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | - Jhill Shah
- Department of PediatricsMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | - Douglas Hayden
- Department of PediatricsMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
| | - Patricia L. Hibberd
- Department of Global HealthBoston University School of Public HealthBostonMassachusettsUSA
| | - Philip Demokritou
- Department of Environmental HealthHarvard T. H. Chan School of Public HealthBostonMassachusettsUSA
- Department of Mechanical and Aerospace EngineeringRutgers University School of Public HealthNew BrunswickNew JerseyUSA
| | - T. Bernard Kinane
- Department of PediatricsMassachusetts General Hospital and Harvard Medical SchoolBostonMassachusettsUSA
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12
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Tang JW, Marr LC, Tellier R, Dancer SJ. Airborne transmission of respiratory viruses including severe acute respiratory syndrome coronavirus 2. Curr Opin Pulm Med 2023; 29:191-196. [PMID: 36866737 PMCID: PMC10090298 DOI: 10.1097/mcp.0000000000000947] [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] [Indexed: 03/04/2023]
Abstract
PURPOSE OF REVIEW The coronavirus disease 2019 pandemic has had a wide-ranging and profound impact on how we think about the transmission of respiratory viruses This review outlines the basis on which we should consider all respiratory viruses as aerosol-transmissible infections, in order to improve our control of these pathogens in both healthcare and community settings. RECENT FINDINGS We present recent studies to support the aerosol transmission of severe acute respiratory syndrome coronavirus 2, and some older studies to demonstrate the aerosol transmissibility of other, more familiar seasonal respiratory viruses. SUMMARY Current knowledge on how these respiratory viruses are transmitted, and the way we control their spread, is changing. We need to embrace these changes to improve the care of patients in hospitals and care homes including others who are vulnerable to severe disease in community settings.
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Affiliation(s)
- Julian W. Tang
- Clinical Microbiology, University Hospitals of Leicester NHS Trust
- Respiratory Sciences, University of Leicester, Leicester, UK
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13
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Li Y, Mao N, Guo L, Guo L, Chen L, Zhao L, Wang Q, Long E. Review of animal transmission experiments of respiratory viruses: Implications for transmission risk of SARS-COV-2 in humans via different routes. RISK ANALYSIS : AN OFFICIAL PUBLICATION OF THE SOCIETY FOR RISK ANALYSIS 2023. [PMID: 36973964 DOI: 10.1111/risa.14129] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 02/22/2023] [Accepted: 02/23/2023] [Indexed: 06/18/2023]
Abstract
Exploring transmission risk of different routes has major implications for epidemic control. However, disciplinary boundaries have impeded the dissemination of epidemic information, have caused public panic about "air transmission," "air-conditioning transmission," and "environment-to-human transmission," and have triggered "hygiene theater." Animal experiments provide experimental evidence for virus transmission, but more attention is paid to whether transmission is driven by droplets or aerosols and using the dichotomy to describe most transmission events. Here, according to characteristics of experiment setups, combined with patterns of human social interactions, we reviewed and grouped animal transmission experiments into four categories-close contact, short-range, fomite, and aerosol exposure experiments-and provided enlightenment, with experimental evidence, on the transmission risk of severe acute respiratory syndrome coronavirus (SARS-COV-2) in humans via different routes. When referring to "air transmission," context should be showed in elaboration results, rather than whether close contact, short or long range is uniformly described as "air transmission." Close contact and short range are the major routes. When face-to-face, unprotected, horizontally directional airflow does promote transmission, due to virus decay and dilution in air, the probability of "air conditioning transmission" is low; the risk of "environment-to-human transmission" highly relies on surface contamination and human behavior based on indirect path of "fomite-hand-mucosa or conjunctiva" and virus decay on surfaces. Thus, when discussing the transmission risk of SARS-CoV-2, we should comprehensively consider the biological basis of virus transmission, environmental conditions, and virus decay. Otherwise, risk of certain transmission routes, such as long-range and fomite transmission, will be overrated, causing public excessive panic, triggering ineffective actions, and wasting epidemic prevention resources.
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Affiliation(s)
- Ying Li
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu, China
| | - Ning Mao
- MOE Key Laboratory of Deep Earth Science and Engineering, Institute for Disaster Management and Reconstruction, Sichuan University, Chengdu, China
| | - Lei Guo
- MOE Key Laboratory of Deep Earth Science and Engineering, Institute for Disaster Management and Reconstruction, Sichuan University, Chengdu, China
| | - Luyao Guo
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu, China
| | - Linlin Chen
- MOE Key Laboratory of Deep Earth Science and Engineering, Institute for Disaster Management and Reconstruction, Sichuan University, Chengdu, China
| | - Li Zhao
- China Academy of Building Research, Beijing, China
| | - Qingqin Wang
- China Academy of Building Research, Beijing, China
| | - Enshen Long
- MOE Key Laboratory of Deep Earth Science and Engineering, College of Architecture and Environment, Sichuan University, Chengdu, China
- MOE Key Laboratory of Deep Earth Science and Engineering, Institute for Disaster Management and Reconstruction, Sichuan University, Chengdu, China
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14
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Assessment of SARS-CoV-2 airborne infection transmission risk in public buses. GEOSCIENCE FRONTIERS 2022; 13. [PMID: 37521135 PMCID: PMC9006420 DOI: 10.1016/j.gsf.2022.101398] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/07/2023]
Abstract
Public transport environments are thought to play a key role in the spread of SARS-CoV-2 worldwide. Indeed, high crowding indexes (i.e. high numbers of people relative to the vehicle size), inadequate clean air supply, and frequent extended exposure durations make transport environments potential hotspots for transmission of respiratory infections. During the COVID-19 pandemic, generic mitigation measures (e.g. physical distancing) have been applied without also considering the airborne transmission route. This is due to the lack of quantified data about airborne contagion risk in transport environments. In this study, we apply a novel combination of close proximity and room-scale risk assessment approaches for people sharing public transport environments to predict their contagion risk due to SARS-CoV-2 respiratory infection. In particular, the individual infection risk of susceptible subjects and the transmissibility of SARS-CoV-2 (expressed through the reproduction number) are evaluated for two types of buses, differing in terms of exposure time and crowding index: urban and long-distance buses. Infection risk and reproduction number are calculated for different scenarios as a function of the ventilation rates (both measured and estimated according to standards), crowding indexes, and travel times. The results show that for urban buses, the close proximity contribution significantly affects the maximum occupancy to maintain a reproductive number of <1. In particular, full occupancy of the bus would be permitted only for an infected subject breathing, whereas for an infected subject speaking, masking would be required. For long-distance buses, full occupancy of the bus can be maintained only if specific mitigation solutions are simultaneously applied. For example, for an infected person speaking for 1 h, appropriate filtration of the recirculated air and simultaneous use of FFP2 masks would permit full occupancy of the bus for a period of almost 8 h. Otherwise, a high percentage of immunized persons (>80%) would be needed.
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15
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Performing under Pressure: Insights into the Diagnostic Testing Burden at a UK National Health Service Clinical Virology Laboratory during the SARS-CoV-2 Pandemic. Viruses 2022; 14:v14102233. [PMID: 36298788 PMCID: PMC9609557 DOI: 10.3390/v14102233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 10/08/2022] [Accepted: 10/10/2022] [Indexed: 11/23/2022] Open
Abstract
UK National Health Service (NHS) Clinical Virology Departments provide a repertoire of tests on clinical samples to detect the presence of viral genomic material or host immune responses to viral infection. In December 2019, a novel coronavirus (SARS-CoV-2) emerged which quickly developed into a global pandemic; NHS laboratories responded rapidly to upscale their testing capabilities. To date, there is little information on the impact of increased SARS-CoV-2 screening on non-SARS-CoV-2 testing within NHS laboratories. This report details the virology test requests received by the Leicester-based NHS Virology laboratory from January 2018 to May 2022. Data show that in spite of a dramatic increase in screening, along with multiple logistic and staffing issues, the Leicester Virology Department was mostly able to maintain the same level of service for non-respiratory virus testing while meeting the new increase in SARS-CoV-2 testing.
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16
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Sachs JD, Karim SSA, Aknin L, Allen J, Brosbøl K, Colombo F, Barron GC, Espinosa MF, Gaspar V, Gaviria A, Haines A, Hotez PJ, Koundouri P, Bascuñán FL, Lee JK, Pate MA, Ramos G, Reddy KS, Serageldin I, Thwaites J, Vike-Freiberga V, Wang C, Were MK, Xue L, Bahadur C, Bottazzi ME, Bullen C, Laryea-Adjei G, Ben Amor Y, Karadag O, Lafortune G, Torres E, Barredo L, Bartels JGE, Joshi N, Hellard M, Huynh UK, Khandelwal S, Lazarus JV, Michie S. The Lancet Commission on lessons for the future from the COVID-19 pandemic. Lancet 2022; 400:1224-1280. [PMID: 36115368 PMCID: PMC9539542 DOI: 10.1016/s0140-6736(22)01585-9] [Citation(s) in RCA: 253] [Impact Index Per Article: 126.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Revised: 07/01/2022] [Accepted: 08/11/2022] [Indexed: 02/03/2023]
Affiliation(s)
- Jeffrey D Sachs
- Center for Sustainable Development, Columbia University, New York, NY, United States.
| | - Salim S Abdool Karim
- Mailman School of Public Health, Columbia University, New York, NY, United States
| | - Lara Aknin
- Department of Psychology, Simon Fraser University, Burnaby, BC, Canada
| | - Joseph Allen
- Department of Environmental Health, Harvard T H Chan School of Public Health, Boston, MA, United States
| | | | - Francesca Colombo
- Health Division, Organisation for Economic Co-operation and Development, Paris, France
| | | | | | - Vitor Gaspar
- Fiscal Affairs Department, International Monetary Fund, Washington, DC, United States
| | | | - Andy Haines
- Department of Public Health, Environments and Society, London School of Hygiene and Tropical Medicine, London, UK; Department of Population Health, London School of Hygiene and Tropical Medicine, London, UK
| | - Peter J Hotez
- National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, United States
| | - Phoebe Koundouri
- Department of International and European Economic Studies, Athens University of Economics and Business, Athens, Greece; Department of Technology, Management and Economics, Technical University of Denmark, Kongens Lyngby, Denmark; European Association of Environmental and Resource Economists, Athens, Greece
| | - Felipe Larraín Bascuñán
- Department of Economics and Administration, Pontificia Universidad Católica de Chile, Santiago, Chile
| | - Jong-Koo Lee
- National Academy of Medicine of Korea, Seoul, Republic of Korea
| | - Muhammad Ali Pate
- Department of Global Health and Population, Harvard T H Chan School of Public Health, Boston, MA, United States
| | | | | | | | - John Thwaites
- Monash Sustainable Development Institute, Monash University, Clayton, VIC, Australia
| | | | - Chen Wang
- National Clinical Research Center for Respiratory Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China; National Clinical Research Center for Respiratory Diseases, China-Japan Friendship Hospital, Beijing, China
| | | | - Lan Xue
- Schwarzman College, Tsinghua University, Beijing, China
| | - Chandrika Bahadur
- The Lancet COVID-19 Commission Regional Task Force: India, New Delhi, India
| | - Maria Elena Bottazzi
- National School of Tropical Medicine, Baylor College of Medicine, Houston, TX, United States
| | - Chris Bullen
- National Institute for Health Innovation, University of Auckland, Auckland, New Zealand
| | | | - Yanis Ben Amor
- Center for Sustainable Development, Columbia University, New York, NY, United States
| | - Ozge Karadag
- Center for Sustainable Development, Columbia University, New York, NY, United States
| | | | - Emma Torres
- United Nations Sustainable Development Solutions Network, New York, NY, United States
| | - Lauren Barredo
- United Nations Sustainable Development Solutions Network, New York, NY, United States
| | - Juliana G E Bartels
- Center for Sustainable Development, Columbia University, New York, NY, United States
| | - Neena Joshi
- United Nations Sustainable Development Solutions Network, New York, NY, United States
| | | | | | | | - Jeffrey V Lazarus
- Barcelona Institute for Global Health (ISGlobal), Hospital Clinic, University of Barcelona, Barcelona, Spain
| | - Susan Michie
- Centre for Behaviour Change, University College London, London, UK
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17
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Luo Q, Ou C, Hang J, Luo Z, Yang H, Yang X, Zhang X, Li Y, Fan X. Role of pathogen-laden expiratory droplet dispersion and natural ventilation explaining a COVID-19 outbreak in a coach bus. BUILDING AND ENVIRONMENT 2022; 220:109160. [PMID: 35615259 PMCID: PMC9122785 DOI: 10.1016/j.buildenv.2022.109160] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2022] [Revised: 04/28/2022] [Accepted: 04/30/2022] [Indexed: 05/30/2023]
Abstract
The influencing mechanism of droplet transmissions inside crowded and poorly ventilated buses on infection risks of respiratory diseases is still unclear. Based on experiments of one-infecting-seven COVID-19 outbreak with an index patient at bus rear, we conducted CFD simulations to investigate integrated effects of initial droplet diameters(tracer gas, 5 μm, 50 μm and 100 μm), natural air change rates per hour(ACH = 0.62, 2.27 and 5.66 h-1 related to bus speeds) and relative humidity(RH = 35% and 95%) on pathogen-laden droplet dispersion and infection risks. Outdoor pressure difference around bus surfaces introduces natural ventilation airflow entering from bus-rear skylight and leaving from the front one. When ACH = 0.62 h-1(idling state), the 30-min-exposure infection risk(TIR) of tracer gas is 15.3%(bus rear) - 11.1%(bus front), and decreases to 3.1%(bus rear)-1.3%(bus front) under ACH = 5.66 h-1(high bus speed).The TIR of large droplets(i.e., 100 μm/50 μm) is almost independent of ACH, with a peak value(∼3.1%) near the index patient, because over 99.5%/97.0% of droplets deposit locally due to gravity. Moreover, 5 μm droplets can disperse further with the increasing ventilation. However, TIR for 5 μm droplets at ACH = 5.66 h-1 stays relatively small for rear passengers(maximum 0.4%), and is even smaller in the bus middle and front(<0.1%). This study verifies that differing from general rooms, most 5 μm droplets deposit on the route through the long-and-narrow bus space with large-area surfaces(L∼11.4 m). Therefore, tracer gas can only simulate fine droplet with little deposition but cannot replace 5-100 μm droplet dispersion in coach buses.
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Affiliation(s)
- Qiqi Luo
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
- Key Laboratory of Tropical Atmosphere-Ocean System (Sun Yat-sen University), Ministry of Education, Zhuhai, 519000, China
| | - Cuiyun Ou
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
- Key Laboratory of Tropical Atmosphere-Ocean System (Sun Yat-sen University), Ministry of Education, Zhuhai, 519000, China
| | - Jian Hang
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
- Key Laboratory of Tropical Atmosphere-Ocean System (Sun Yat-sen University), Ministry of Education, Zhuhai, 519000, China
| | - Zhiwen Luo
- School of the Built Environment, University of Reading, Reading, UK
| | - Hongyu Yang
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
- Key Laboratory of Tropical Atmosphere-Ocean System (Sun Yat-sen University), Ministry of Education, Zhuhai, 519000, China
| | - Xia Yang
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
- Key Laboratory of Tropical Atmosphere-Ocean System (Sun Yat-sen University), Ministry of Education, Zhuhai, 519000, China
| | - Xuelin Zhang
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
- Key Laboratory of Tropical Atmosphere-Ocean System (Sun Yat-sen University), Ministry of Education, Zhuhai, 519000, China
| | - Yuguo Li
- Department of Mechanical Engineering, The University of Hong Kong, Hong Kong SAR, China
| | - Xiaodan Fan
- School of Atmospheric Sciences, Sun Yat-sen University, and Southern Marine Science and Engineering Guangdong Laboratory (Zhuhai), Zhuhai, China
- Key Laboratory of Tropical Atmosphere-Ocean System (Sun Yat-sen University), Ministry of Education, Zhuhai, 519000, China
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18
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Duval D, Palmer JC, Tudge I, Pearce-Smith N, O'Connell E, Bennett A, Clark R. Long distance airborne transmission of SARS-CoV-2: rapid systematic review. BMJ 2022; 377:e068743. [PMID: 35768139 PMCID: PMC9240778 DOI: 10.1136/bmj-2021-068743] [Citation(s) in RCA: 32] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 05/04/2022] [Indexed: 12/22/2022]
Abstract
OBJECTIVES To evaluate the potential for long distance airborne transmission of SARS-CoV-2 in indoor community settings and to investigate factors that might influence transmission. DESIGN Rapid systematic review and narrative synthesis. DATA SOURCES Medline, Embase, medRxiv, Arxiv, and WHO COVID-19 Research Database for studies published from 27 July 2020 to 19 January 2022; existing relevant rapid systematic review for studies published from 1 January 2020 to 27 July 2020; and citation analysis in Web of Science and Cocites. ELIGIBILITY CRITERIA FOR STUDY SELECTION Observational studies reporting on transmission events in indoor community (non-healthcare) settings in which long distance airborne transmission of SARS-CoV-2 was the most likely route. Studies such as those of household transmission where the main transmission route was likely to be close contact or fomite transmission were excluded. DATA EXTRACTION AND SYNTHESIS Data extraction was done by one reviewer and independently checked by a second reviewer. Primary outcomes were SARS-CoV-2 infections through long distance airborne transmission (>2 m) and any modifying factors. Methodological quality of included studies was rated using the quality criteria checklist, and certainty of primary outcomes was determined using the Grading of Recommendations, Assessment, Development, and Evaluation (GRADE) framework. Narrative synthesis was themed by setting. RESULTS 22 reports relating to 18 studies were identified (methodological quality was high in three, medium in five, and low in 10); all the studies were outbreak investigations. Long distance airborne transmission was likely to have occurred for some or all transmission events in 16 studies and was unclear in two studies (GRADE: very low certainty). In the 16 studies, one or more factors plausibly increased the likelihood of long distance airborne transmission, particularly insufficient air replacement (very low certainty), directional air flow (very low certainty), and activities associated with increased emission of aerosols, such as singing or speaking loudly (very low certainty). In 13 studies, the primary cases were reported as being asymptomatic, presymptomatic, or around symptom onset at the time of transmission. Although some of the included studies were well conducted outbreak investigations, they remain at risk of bias owing to study design and do not always provide the level of detail needed to fully assess transmission routes. CONCLUSION This rapid systematic review found evidence suggesting that long distance airborne transmission of SARS-CoV-2 might occur in indoor settings such as restaurants, workplaces, and venues for choirs, and identified factors such as insufficient air replacement that probably contributed to transmission. These results strengthen the need for mitigation measures in indoor settings, particularly the use of adequate ventilation. SYSTEMATIC REVIEW REGISTRATION PROSPERO CRD42021236762.
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Affiliation(s)
- Daphne Duval
- COVID-19 Rapid Evidence Service, UK Health Security Agency, London, UK
| | - Jennifer C Palmer
- COVID-19 Rapid Evidence Service, UK Health Security Agency, London, UK
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK
- Population Health Science, Bristol Medical School, University of Bristol, Bristol, UK
| | - Isobel Tudge
- COVID-19 Rapid Evidence Service, UK Health Security Agency, London, UK
| | | | - Emer O'Connell
- COVID-19 Advice and Guidance, UK Health Security Agency, London, UK
| | - Allan Bennett
- Biosafety, Air, and Water Microbiology Group, Research and Evaluation, UK Health Security Agency, Porton, UK
| | - Rachel Clark
- COVID-19 Rapid Evidence Service, UK Health Security Agency, London, UK
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19
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Abstract
The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) delta variant transmits much more rapidly than prior SARS-CoV-2 viruses. The primary mode of transmission is via short range aerosols that are emitted from the respiratory tract of an index case. There is marked heterogeneity in the spread of this virus, with 10% to 20% of index cases contributing to 80% of secondary cases, while most index cases have no subsequent transmissions. Vaccination, ventilation, masking, eye protection, and rapid case identification with contact tracing and isolation can all decrease the transmission of this virus.
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Affiliation(s)
- Eric A Meyerowitz
- Montefiore Medical Center, 111 East 210th Street, Bronx, NY 10467, USA.
| | - Aaron Richterman
- Hospital of the University of Pennsylvania, 3400 Spruce Street, Philadelphia, PA 19104, USA
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20
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Brown E, Nelson N, Gubbins S, Colenutt C. Airborne Transmission of Foot-and-Mouth Disease Virus: A Review of Past and Present Perspectives. Viruses 2022; 14:1009. [PMID: 35632750 PMCID: PMC9145556 DOI: 10.3390/v14051009] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2022] [Revised: 04/25/2022] [Accepted: 05/05/2022] [Indexed: 02/01/2023] Open
Abstract
The primary transmission route for foot-and-mouth disease (FMD), a contagious viral disease of cloven-hoofed animals, is by direct contact with infected animals. Yet indirect methods of transmission, such as via the airborne route, have been shown to play an important role in the spread of the disease. Airborne transmission of FMD is referred to as a low probability- high consequence event as a specific set of factors need to coincide to facilitate airborne spread. When conditions are favourable, airborne virus may spread rapidly and cause disease beyond the imposed quarantine zones, thus complicating control measures. Therefore, it is important to understand the nature of foot-and-mouth disease virus (FMDV) within aerosols; how aerosols are generated, viral load, how far aerosols could travel and survive under different conditions. Various studies have investigated emissions from infected animals under laboratory conditions, while others have incorporated experimental data in mathematical models to predict and trace outbreaks of FMD. However, much of the existing literature focussing on FMDV in aerosols describe work which was undertaken over 40 years ago. The aim of this review is to revisit existing knowledge and investigate how modern instrumentation and modelling approaches can improve our understanding of airborne transmission of FMD.
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Affiliation(s)
- Emma Brown
- The Pirbright Institute, Ash Road, Pirbright, Surrey GU24 0NF, UK; (S.G.); (C.C.)
| | - Noel Nelson
- The Met Office, FitzRoy Road, Exeter, Devon EX1 3PB, UK;
| | - Simon Gubbins
- The Pirbright Institute, Ash Road, Pirbright, Surrey GU24 0NF, UK; (S.G.); (C.C.)
| | - Claire Colenutt
- The Pirbright Institute, Ash Road, Pirbright, Surrey GU24 0NF, UK; (S.G.); (C.C.)
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21
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Fisman DN, Amoako A, Tuite AR. Impact of population mixing between vaccinated and unvaccinated subpopulations on infectious disease dynamics: implications for SARS-CoV-2 transmission. CMAJ 2022; 194:E573-E580. [PMID: 35470204 PMCID: PMC9054088 DOI: 10.1503/cmaj.212105] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/23/2022] [Indexed: 12/19/2022] Open
Abstract
Background: The speed of vaccine development has been a singular achievement during the COVID-19 pandemic, although uptake has not been universal. Vaccine opponents often frame their opposition in terms of the rights of the unvaccinated. We sought to explore the impact of mixing of vaccinated and unvaccinated populations on risk of SARS-CoV-2 infection among vaccinated people. Methods: We constructed a simple susceptible–infectious–recovered compartmental model of a respiratory infectious disease with 2 connected subpopulations: people who were vaccinated and those who were unvaccinated. We simulated a spectrum of patterns of mixing between vaccinated and unvaccinated groups that ranged from random mixing to complete like-with-like mixing (complete assortativity), in which people have contact exclusively with others with the same vaccination status. We evaluated the dynamics of an epidemic within each subgroup and in the population as a whole. Results: We found that the risk of infection was markedly higher among unvaccinated people than among vaccinated people under all mixing assumptions. The contact-adjusted contribution of unvaccinated people to infection risk was disproportionate, with unvaccinated people contributing to infections among those who were vaccinated at a rate higher than would have been expected based on contact numbers alone. We found that as like-with-like mixing increased, attack rates among vaccinated people decreased from 15% to 10% (and increased from 62% to 79% among unvaccinated people), but the contact-adjusted contribution to risk among vaccinated people derived from contact with unvaccinated people increased. Interpretation: Although risk associated with avoiding vaccination during a virulent pandemic accrues chiefly to people who are unvaccinated, their choices affect risk of viral infection among those who are vaccinated in a manner that is disproportionate to the portion of unvaccinated people in the population.
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Affiliation(s)
- David N Fisman
- Dalla Lana School of Public Health (Fisman, Amoako, Tuite), University of Toronto, Toronto, Ont.; Centre for Immunization Readiness (Tuite), Public Health Agency of Canada, Ottawa, Ont.
| | - Afia Amoako
- Dalla Lana School of Public Health (Fisman, Amoako, Tuite), University of Toronto, Toronto, Ont.; Centre for Immunization Readiness (Tuite), Public Health Agency of Canada, Ottawa, Ont
| | - Ashleigh R Tuite
- Dalla Lana School of Public Health (Fisman, Amoako, Tuite), University of Toronto, Toronto, Ont.; Centre for Immunization Readiness (Tuite), Public Health Agency of Canada, Ottawa, Ont
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22
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Archer J, McCarthy LP, Symons HE, Watson NA, Orton CM, Browne WJ, Harrison J, Moseley B, Philip KEJ, Calder JD, Shah PL, Bzdek BR, Costello D, Reid JP. Comparing aerosol number and mass exhalation rates from children and adults during breathing, speaking and singing. Interface Focus 2022; 12:20210078. [PMID: 35261733 PMCID: PMC8831083 DOI: 10.1098/rsfs.2021.0078] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 01/04/2022] [Indexed: 12/14/2022] Open
Abstract
Aerosol particles of respirable size are exhaled when individuals breathe, speak and sing and can transmit respiratory pathogens between infected and susceptible individuals. The COVID-19 pandemic has brought into focus the need to improve the quantification of the particle number and mass exhalation rates as one route to provide estimates of viral shedding and the potential risk of transmission of viruses. Most previous studies have reported the number and mass concentrations of aerosol particles in an exhaled plume. We provide a robust assessment of the absolute particle number and mass exhalation rates from measurements of minute ventilation using a non-invasive Vyntus Hans Rudolf mask kit with straps housing a rotating vane spirometer along with measurements of the exhaled particle number concentrations and size distributions. Specifically, we report comparisons of the number and mass exhalation rates for children (12-14 years old) and adults (19-72 years old) when breathing, speaking and singing, which indicate that child and adult cohorts generate similar amounts of aerosol when performing the same activity. Mass exhalation rates are typically 0.002-0.02 ng s-1 from breathing, 0.07-0.2 ng s-1 from speaking (at 70-80 dBA) and 0.1-0.7 ng s-1 from singing (at 70-80 dBA). The aerosol exhalation rate increases with increasing sound volume for both children and adults when both speaking and singing.
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Affiliation(s)
| | | | | | - Natalie A. Watson
- Department of Ear, Nose and Throat Surgery, Guy's and St Thomas' NHS Foundation Trust, London, UK
| | - Christopher M. Orton
- Department of Respiratory Medicine, Royal Brompton Hospital, London, UK
- Department of Respiratory Medicine, Chelsea and Westminster Hospital, London, UK
- National Heart and Lung Institute, Imperial College London, Guy Scadding Building, London, UK
| | | | | | - Benjamin Moseley
- Department of Respiratory Medicine, Chelsea and Westminster Hospital, London, UK
| | - Keir E. J. Philip
- Department of Respiratory Medicine, Royal Brompton Hospital, London, UK
- National Heart and Lung Institute, Imperial College London, Guy Scadding Building, London, UK
| | - James D. Calder
- Department of Bioengineering, Imperial College London, London, UK
- Fortius Clinic, Fitzhardinge Street, London, UK
| | - Pallav L. Shah
- Department of Respiratory Medicine, Royal Brompton Hospital, London, UK
- Department of Respiratory Medicine, Chelsea and Westminster Hospital, London, UK
- National Heart and Lung Institute, Imperial College London, Guy Scadding Building, London, UK
| | | | - Declan Costello
- Ear, Nose and Throat Department, Wexham Park Hospital, Slough, UK
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23
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Curran ET. Maintaining safe office spaces to minimise risks of SARS-CoV-2 transmission. Infect Dis Health 2022; 27:142-148. [PMID: 35473679 PMCID: PMC8977437 DOI: 10.1016/j.idh.2022.03.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2021] [Revised: 03/16/2022] [Accepted: 03/17/2022] [Indexed: 11/03/2022]
Abstract
BACKGROUND SARS-CoV-2 can be transmitted within offices. Traditional respiratory transmission modes have undergone reassessment and a new paradigm has emerged. This paradigm needs examining prior to identifying control measures to prevent office acquired infections (OAI). METHODS An ongoing assessment of the SARS-CoV-2 transmission literature, including international public health guidance, began 30/1/2020 and continued to submission 7/2/2022. The evidence for the established respiratory transmission paradigm (either droplet or aerosols) and that of a newly emerging paradigm (aerosol and/or droplets) were explored. Based on the new paradigm control measures needed to minimise OAI were produced. RESULTS The old paradigm of respiratory transmission of being either droplet or airborne cannot be evidenced. SARS-CoV-2 is emitted in virus laden particles that can be inhaled and/or sprayed on facial mucous membranes (Airborne being the dominant route). Office hygiene measures include: minimising the opportunities for the virus to enter the building. Reducing the susceptibility of people to the virus. Minimising exposure risks within offices, and optimising success in deployment. CONCLUSION Standard office hygiene precautions are needed to reduce OAI risks from SARS-CoV-2. Efforts should focus on enabling the smooth functioning of the office whilst minimising risks that the virus will transmit therein. This includes: local risk assessments as transmission risks vary based on building design, ventilation, capacity, and ways of working. Additionally, using experts to optimise ventilation systems.
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Affiliation(s)
- Evonne T Curran
- Glasgow Caledonian University, Cowcaddens, Glasgow, Scotland G4 OBA, UK.
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24
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Davidse A, Zare RN. Effect of Relative Humidity in Air on the Transmission of Respiratory Viruses. MOLECULAR FRONTIERS JOURNAL 2021. [DOI: 10.1142/s252973252140006x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Viral respiratory infections have plagued mankind over its known history. Unfortunately, there has been a lack of meaningful progress in preventing the spread of viral respiratory infections globally. The central dogma appears to be that viruses are the villains. This framing focuses on a viral load balance (VLB) in the air. It follows that physical dilution through various means have been the primary focus of attempts to reduce the spread of infections. The problem of obesity provides a good example of how paradigm blindness can slow down progress in a field. Obesity has been framed as an energy balance disorder that blames overeating and lack of exercise for weight gain. Reframing obesity as a disorder of fat metabolism and storage caused by the quantity and quality of carbohydrates in the diet, referred to as the carbohydrate-insulin model (CIM), opened an alternative line of questioning with a testable hypothesis. Similarly, we postulate an alternative way to frame the spread of viral respiratory infections that would lead to new insights and potentially new ways to prevent infections. It has long been recognized that viral respiratory infections show a pronounced seasonal variation, referred to as seasonal forging, such that they increase in the winter but decrease or virtually disappear in the summer. In temperate regions, people spend over 90% of their time indoors. This is, therefore, where most respiratory infections are expected to occur. Evidence has been accumulating for decades on the strong correlation between variations in indoor relative humidity (RH) and variations in infection rates. Within a RH Goldilocks zone of 40%-60%, encapsulated viruses like influenza and SARS are optimally inactivated outside the infected host. Below 40% and above 80%, viruses can survive for extended periods in the air or on surfaces. This may explain in part the seasonality of infections as the indoor level of RH in winter is typically about 20% and above 40% in summer in temperate regions. However, the mechanism for the inactivation at midrange RH (in summer) is not well understood. This paper offers a hypothesis that could explain these observations. We have demonstrated that H2O2 and other reactive oxygen species (ROS) are formed spontaneously at the water-air interface of pure water microdroplets. Using only water and a nebulizing gas in the presence of oxygen, we have demonstrated the significant disinfectant potential of pure water microdroplets caused by the activity of H2O2 and other ROS. We postulate that spontaneous H2O2 and ROS formation in viruses containing exhaled microdroplets have a similar virucidal effect at mid-range RH. The droplet evaporation rate is sufficient to concentrate the solutes and provide enough time for reactions to occur at significantly higher rates than in bulk solutions. The concentration of H2O2 has also been shown to be positively correlated to RH. In addition, several other ROS/RNS may be present or formed through interactions with H2O2 that may act as even more effective virucide disinfectants to inactivate the virus. Below RH 40% evaporation happens too rapidly for these reactions to make an impact before the droplet is desiccated, and above RH 80% the solutes remain too diluted. Rapid inactivation of viruses at midrange RH may therefore play a greater role in preventing infections than physical dilution of virus load in the air through excessive mechanical ventilation. Similar to obesity, we suggest that a new paradigm that considers virus infectivity outside the host rather than the virus load balance in the air alone could greatly contribute to our understanding of respiratory infections. The proposed new “Relative Humidity Infectivity” RHI paradigm could explain the causal mechanisms underlying seasonal respiratory infections. This can point to better prevention strategies that avoid further distortion of our indoor environment and create conditions within which humans can thrive and be optimally protected. We need more focus on testing the various hypotheses and more data to determine which of the two paradigms will lead us in the right direction or how to use the best of both in an optimal combination. The stakes cannot be higher, and the potential for eradicating future viral respiratory pandemics with nature-based solutions may be right under our noses, literally.
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Affiliation(s)
- Adriaan Davidse
- PO Box 93167 Headon PO, Burlington, Ontario, L7M 4A3, Canada
| | - Richard N. Zare
- Department of Chemistry, Stanford University, Stanford, CA 94305 USA
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