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Zhang Y, Shankar SN, Vass WB, Lednicky JA, Fan ZH, Agdas D, Makuch R, Wu CY. Air Change Rate and SARS-CoV-2 Exposure in Hospitals and Residences: A Meta-Analysis. AEROSOL SCIENCE AND TECHNOLOGY : THE JOURNAL OF THE AMERICAN ASSOCIATION FOR AEROSOL RESEARCH 2024; 58:217-243. [PMID: 38764553 PMCID: PMC11101186 DOI: 10.1080/02786826.2024.2312178] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Accepted: 01/16/2024] [Indexed: 05/21/2024]
Abstract
As SARS-CoV-2 swept across the globe, increased ventilation and implementation of air cleaning were emphasized by the US CDC and WHO as important strategies to reduce the risk of inhalation exposure to the virus. To assess whether higher ventilation and air cleaning rates lead to lower exposure risk to SARS-CoV-2, 1274 manuscripts published between April 2020 and September 2022 were screened using key words "airborne SARS-CoV-2 or "SARS-CoV-2 aerosol". Ninety-three studies involved air sampling at locations with known sources (hospitals and residences) were selected and associated data were compiled. Two metrics were used to assess exposure risk: SARS-CoV-2 concentration and SARS-CoV-2 detection rate in air samples. Locations were categorized by type (hospital or residence) and proximity to the sampling location housing the isolated/quarantined patient (primary or secondary). The results showed that hospital wards had lower airborne virus concentrations than residential isolation rooms. A negative correlation was found between airborne virus concentrations in primary-occupancy areas and air changes per hour (ACH). In hospital settings, sample positivity rates were significantly reduced in secondary-occupancy areas compared to primary-occupancy areas, but they were similar across sampling locations in residential settings. ACH and sample positivity rates were negatively correlated, though the effect was diminished when ACH values exceeded 8. While limitations associated with diverse sampling protocols exist, data considered by this meta-analysis support the notion that higher ACH may reduce exposure risks to the virus in ambient air.
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Affiliation(s)
- Yuetong Zhang
- Department of Environmental Engineering Sciences, University of Florida, Gainesville, Florida, USA
- Department of Mechanical Engineering, University of British Columbia, Vancouver, British Columnia, Canada
| | - Sripriya Nannu Shankar
- Department of Environmental Engineering Sciences, University of Florida, Gainesville, Florida, USA
- Department of Environmental & Public Health Sciences, University of Cincinnati, Cincinnati, Ohio, USA
| | - William B. Vass
- Department of Environmental Engineering Sciences, University of Florida, Gainesville, Florida, USA
| | - John A. Lednicky
- Department of Environmental and Global Health, University of Florida, Gainesville, Florida, USA
- Emerging Pathogens Institute, University of Florida, Gainesville, Florida, USA
| | - Z. Hugh Fan
- Mechanical and Aerospace Engineering, University of Florida, Gainesville, Florida, USA
- J. Crayton Pruitt Family Department of Biomedical Engineering, University of Florida, Gainesville, Florida, USA
| | - Duzgun Agdas
- Engineering School of Sustainable Infrastructure & Environment, University of Florida, Gainesville, Florida, USA
| | - Robert Makuch
- Department of Biostatistics, Yale University School of Public Health, New Haven, Connecticut, USA
| | - Chang-Yu Wu
- Department of Environmental Engineering Sciences, University of Florida, Gainesville, Florida, USA
- Department of Chemical, Environmental, and Materials Engineering, University of Miami, Coral Gables, Florida, USA
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2
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Silva PG, Branco PTBS, Soares RRG, Mesquita JR, Sousa SIV. SARS-CoV-2 air sampling: A systematic review on the methodologies for detection and infectivity. INDOOR AIR 2022; 32:e13083. [PMID: 36040285 PMCID: PMC9538005 DOI: 10.1111/ina.13083] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 07/06/2022] [Accepted: 07/08/2022] [Indexed: 06/15/2023]
Abstract
This systematic review aims to present an overview of the current aerosol sampling methods (and equipment) being used to investigate the presence of SARS-CoV-2 in the air, along with the main parameters reported in the studies that are essential to analyze the advantages and disadvantages of each method and perspectives for future research regarding this mode of transmission. A systematic literature review was performed on PubMed/MEDLINE, Web of Science, and Scopus to assess the current air sampling methodologies being applied to SARS-CoV-2. Most of the studies took place in indoor environments and healthcare settings and included air and environmental sampling. The collection mechanisms used were impinger, cyclone, impactor, filters, water-based condensation, and passive sampling. Most of the reviewed studies used RT-PCR to test the presence of SARS-CoV-2 RNA in the collected samples. SARS-CoV-2 RNA was detected with all collection mechanisms. From the studies detecting the presence of SARS-CoV-2 RNA, fourteen assessed infectivity. Five studies detected viable viruses using impactor, water-based condensation, and cyclone collection mechanisms. There is a need for a standardized protocol for sampling SARS-CoV-2 in air, which should also account for other influencing parameters, including air exchange ratio in the room sampled, relative humidity, temperature, and lighting conditions.
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Affiliation(s)
- Priscilla G Silva
- Laboratory for Integrative and Translational Research in Population Health (ITR), Porto, Portugal
- School of Medicine and Biomedical Sciences (ICBAS), University of Porto, Porto, Portugal
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Porto, Portugal
- ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
- Epidemiology Research Unit (EPI Unit), Institute of Public Health, University of Porto, Porto, Portugal
| | - Pedro T B S Branco
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Porto, Portugal
- ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
| | - Ruben R G Soares
- Department of Biochemistry and Biophysics, Science for Life Laboratory, Stockholm University, Solna, Sweden
- Division of Nanobiotechnology, Department of Protein Science, Science for Life Laboratory, KTH Royal Institute of Technology, Solna, Sweden
| | - João R Mesquita
- Laboratory for Integrative and Translational Research in Population Health (ITR), Porto, Portugal
- Epidemiology Research Unit (EPI Unit), Institute of Public Health, University of Porto, Porto, Portugal
| | - Sofia I V Sousa
- LEPABE - Laboratory for Process Engineering, Environment, Biotechnology and Energy, Faculty of Engineering, University of Porto, Porto, Portugal
- ALiCE - Associate Laboratory in Chemical Engineering, Faculty of Engineering, University of Porto, Porto, Portugal
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3
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Schoen CN, Morgan E, Leftwich HK, Rogers C, Soorneedi A, Suther C, Moore MD. Failure to Detect SARS-CoV-2 RNA in the Air During Active Labor in Mothers Who Recently Tested Positive. Front Public Health 2022; 10:881613. [PMID: 35570919 PMCID: PMC9093214 DOI: 10.3389/fpubh.2022.881613] [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: 02/22/2022] [Accepted: 03/31/2022] [Indexed: 12/03/2022] Open
Abstract
The risk of potential SARS-CoV-2 transmission by infected mothers during labor and delivery has not been investigated in-depth. This work collected air samples close to (respiratory droplets) and more distant from (aerosol generation) unvaccinated patients who had previously tested positive for SARS-CoV-2 during labor within 5 days of a positive test. All but one of the patients wore masks during the delivery, and delivery was carried out in either birthing or negative pressure isolation rooms. Our work failed to detect SARS-CoV-2 RNA in any air samples for all of the six patients who gave birth vaginally, despite validation of the limit of detection of the samplers. In sum, this brief report provides initial evidence that the risk of airborne transmission of SARS-CoV-2 during labor may be mitigated by the use of masks and high ventilation rates common in many modern U.S. medical facilities; however more work is needed to fully evaluate the risk of SARS-CoV-2 transmission during labor and maternal pushing.
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Affiliation(s)
- Corina N Schoen
- Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Massachusetts Medical School-Baystate, Springfield, MA, United States
| | - Elizabeth Morgan
- Division of Maternal Fetal Medicine, Department of Obstetrics and Gynecology, University of Massachusetts Medical School-Baystate, Springfield, MA, United States
| | - Heidi K Leftwich
- Division of Maternal-Fetal Medicine, Department of Obstetrics and Gynecology, University of Massachusetts Chan Medical School/UMASS Memorial Health, Worcester, MA, United States
| | - Christine Rogers
- Department of Environmental Health Sciences, School of Public Health & Health Sciences, University of Massachusetts-Amherst, Amherst, MA, United States
| | - Anand Soorneedi
- Department of Food Science, University of Massachusetts-Amherst, Amherst, MA, United States
| | - Cassandra Suther
- Department of Food Science, University of Massachusetts-Amherst, Amherst, MA, United States
| | - Matthew D Moore
- Department of Food Science, University of Massachusetts-Amherst, Amherst, MA, United States
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Myers NT, Laumbach RJ, Black KG, Ohman‐Strickland P, Alimokhtari S, Legard A, De Resende A, Calderón L, Lu FT, Mainelis G, Kipen HM. Portable air cleaners and residential exposure to SARS-CoV-2 aerosols: A real-world study. INDOOR AIR 2022; 32:e13029. [PMID: 35481935 PMCID: PMC9111720 DOI: 10.1111/ina.13029] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/09/2022] [Revised: 03/22/2022] [Accepted: 04/02/2022] [Indexed: 05/04/2023]
Abstract
Individuals with COVID-19 who do not require hospitalization are instructed to self-isolate in their residences. Due to high secondary infection rates in household members, there is a need to understand airborne transmission of SARS-CoV-2 within residences. We report the first naturalistic intervention study suggesting a reduction of such transmission risk using portable air cleaners (PACs) with HEPA filters. Seventeen individuals with newly diagnosed COVID-19 infection completed this single-blind, crossover, randomized study. Total and size-fractionated aerosol samples were collected simultaneously in the self-isolation room with the PAC (primary) and another room (secondary) for two consecutive 24-h periods, one period with HEPA filtration and the other with the filter removed (sham). Seven out of sixteen (44%) air samples in primary rooms were positive for SARS-CoV-2 RNA during the sham period. With the PAC operated at its lowest setting (clean air delivery rate [CADR] = 263 cfm) to minimize noise, positive aerosol samples decreased to four out of sixteen residences (25%; p = 0.229). A slight decrease in positive aerosol samples was also observed in the secondary room. As the world confronts both new variants and limited vaccination rates, our study supports this practical intervention to reduce the presence of viral aerosols in a real-world setting.
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Affiliation(s)
- Nirmala T. Myers
- Department of Environmental SciencesRutgers UniversityNew BrunswickNew JerseyUSA
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
| | - Robert J. Laumbach
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
- Department of Environmental and Occupational Health and JusticeRutgers UniversityPiscatawayNew JerseyUSA
| | - Kathleen G. Black
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
| | - Pamela Ohman‐Strickland
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
- Department of Biostatistics and EpidemiologyRutgers School of Public HealthRutgers UniversityPiscatawayNew JerseyUSA
| | - Shahnaz Alimokhtari
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
| | - Alicia Legard
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
| | - Adriana De Resende
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
| | - Leonardo Calderón
- Department of Environmental SciencesRutgers UniversityNew BrunswickNew JerseyUSA
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
| | - Frederic T. Lu
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
| | - Gediminas Mainelis
- Department of Environmental SciencesRutgers UniversityNew BrunswickNew JerseyUSA
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
| | - Howard M. Kipen
- Rutgers Environmental and Occupational Health Sciences InstituteRutgers UniversityPiscatawayNew JerseyUSA
- Department of Environmental and Occupational Health and JusticeRutgers UniversityPiscatawayNew JerseyUSA
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5
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Viral load of SARS-CoV-2 in droplets and bioaerosols directly captured during breathing, speaking and coughing. Sci Rep 2022; 12:3484. [PMID: 35241703 PMCID: PMC8894466 DOI: 10.1038/s41598-022-07301-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 02/16/2022] [Indexed: 02/08/2023] Open
Abstract
Determining the viral load and infectivity of SARS-CoV-2 in macroscopic respiratory droplets, bioaerosols, and other bodily fluids and secretions is important for identifying transmission modes, assessing risks and informing public health guidelines. Here we show that viral load of SARS-CoV-2 Ribonucleic Acid (RNA) in participants’ naso-pharyngeal (NP) swabs positively correlated with RNA viral load they emitted in both droplets >10 \documentclass[12pt]{minimal}
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\begin{document}$$\upmu \hbox {m}$$\end{document}μm and bioaerosols <10 \documentclass[12pt]{minimal}
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\begin{document}$$\upmu \hbox {m}$$\end{document}μm directly captured during the combined expiratory activities of breathing, speaking and coughing using a standardized protocol, although the NP swabs had \documentclass[12pt]{minimal}
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\begin{document}$$\approx$$\end{document}≈ 10\documentclass[12pt]{minimal}
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\begin{document}$$^3\times$$\end{document}3× more RNA on average. By identifying highly-infectious individuals (maximum of 18,000 PFU/mL in NP), we retrieved higher numbers of SARS-CoV-2 RNA gene copies in bioaerosol samples (maximum of 4.8\documentclass[12pt]{minimal}
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\begin{document}$${\times }10^{5}$$\end{document}×105 gene copies/mL and minimum cycle threshold of 26.2) relative to other studies. However, all attempts to identify infectious virus in size-segregated droplets and bioaerosols were negative by plaque assay (0 of 58). This outcome is partly attributed to the insufficient amount of viral material in each sample (as indicated by SARS-CoV-2 gene copies) or may indicate no infectious virus was present in such samples, although other possible factors are identified.
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6
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SARS-CoV-2 Detection in air samples from inside heating, ventilation, and air conditioning (HVAC) systems- COVID surveillance in student dorms. Am J Infect Control 2022; 50:330-335. [PMID: 34688726 PMCID: PMC8530765 DOI: 10.1016/j.ajic.2021.10.009] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2021] [Revised: 10/04/2021] [Accepted: 10/05/2021] [Indexed: 01/22/2023]
Abstract
Background The COVID-19 pandemic affected universities and institutions and caused campus shutdowns with a transition to online teaching models. To detect infections that might spread on campus, we pursued research towards detecting SARS-CoV-2 in air samples inside student dorms. Methods We sampled air in 2 large dormitories for 3.5 months and a separate isolation suite containing a student who had tested positive for COVID-19. We developed novel techniques employing 4 methods to collect air samples: Filter Cassettes, Button Sampler, BioSampler, and AerosolSense sampler combined with direct qRT-PCR SARS-CoV-2 analysis. Results For the 2 large dorms with the normal student population, we detected SARS-CoV-2 in 11 samples. When compared with student nasal swab qRT-PCR testing, we detected SARS-CoV-2 in air samples when a PCR positive COVID-19 student was living on the same floor of the sampling location with a detection rate of 75%. For the isolation dorm, we had a 100% SARS-CoV-2 detection rate with AerosolSense sampler. Conclusions Our data suggest air sampling may be an important SARS-CoV-2 surveillance technique, especially for buildings with congregant living settings (dorms, correctional facilities, barracks). Future building designs and public health policies should consider implementation of Heating, Ventilation, and Air Conditioning surveillance.
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Lane MA, Walawender M, Webster AS, Brownsword EA, Ingersoll JM, Miller C, Waggoner J, Uyeki TM, Lindsley WG, Kraft CS. Sampling for SARS-CoV-2 Aerosols in Hospital Patient Rooms. Viruses 2021; 13:2347. [PMID: 34960615 PMCID: PMC8703426 DOI: 10.3390/v13122347] [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: 10/21/2021] [Revised: 11/12/2021] [Accepted: 11/19/2021] [Indexed: 12/21/2022] Open
Abstract
Evidence varies as to how far aerosols spread from individuals infected with SARS-CoV-2 in hospital rooms. We investigated the presence of aerosols containing SARS-CoV-2 inside of dedicated COVID-19 patient rooms. Three National Institute for Occupational Safety and Health BC 251 two-stage cyclone samplers were set up in each patient room for a six-hour sampling period. Samplers were place on tripods, which each held two samplers at various heights above the floor. Extracted samples underwent reverse transcription polymerase chain reaction for selected gene regions of the SARS-CoV-2 virus nucleocapsid. Patient medical data were compared between participants in rooms where virus-containing aerosols were detected and those where they were not. Of 576 aerosols samples collected from 19 different rooms across 32 participants, 3% (19) were positive for SARS-CoV-2, the majority from near the head and foot of the bed. Seven of the positive samples were collected inside a single patient room. No significant differences in participant clinical characteristics were found between patients in rooms with positive and negative aerosol samples. SARS-CoV-2 viral aerosols were detected from the patient rooms of nine participants (28%). These findings provide reassurance that personal protective equipment that was recommended for this virus is appropriate given its spread in hospital rooms.
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Affiliation(s)
- Morgan A. Lane
- Division of Infectious Diseases, Department of Medicine, Emory University, Atlanta, GA 30322, USA; (A.S.W.); (E.A.B.); (J.W.); (C.S.K.)
| | - Maria Walawender
- Rollins School of Public Health, Emory University, Atlanta, GA 30322, USA;
| | - Andrew S. Webster
- Division of Infectious Diseases, Department of Medicine, Emory University, Atlanta, GA 30322, USA; (A.S.W.); (E.A.B.); (J.W.); (C.S.K.)
- Department of Infectious Diseases, Atlanta VA Health Care System, Decatur, GA 30033, USA
| | - Erik A. Brownsword
- Division of Infectious Diseases, Department of Medicine, Emory University, Atlanta, GA 30322, USA; (A.S.W.); (E.A.B.); (J.W.); (C.S.K.)
| | - Jessica M. Ingersoll
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA 30322, USA; (J.M.I.); (C.M.)
| | - Candace Miller
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA 30322, USA; (J.M.I.); (C.M.)
| | - Jesse Waggoner
- Division of Infectious Diseases, Department of Medicine, Emory University, Atlanta, GA 30322, USA; (A.S.W.); (E.A.B.); (J.W.); (C.S.K.)
- Emory Healthcare, Atlanta, GA 30322, USA
| | - Timothy M. Uyeki
- Influenza Division, National Center for Immunization and Respiratory Diseases, Centers for Disease Control and Prevention, Atlanta, GA 30322, USA;
| | - William G. Lindsley
- National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention, Morgantown, WV 26508, USA;
| | - Colleen S. Kraft
- Division of Infectious Diseases, Department of Medicine, Emory University, Atlanta, GA 30322, USA; (A.S.W.); (E.A.B.); (J.W.); (C.S.K.)
- Department of Pathology and Laboratory Medicine, Emory University, Atlanta, GA 30322, USA; (J.M.I.); (C.M.)
- Emory Healthcare, Atlanta, GA 30322, USA
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Robie ER, Abdelgadir A, Binder RA, Gray GC. Live SARS-CoV-2 is difficult to detect in patient aerosols. Influenza Other Respir Viruses 2021; 15:554-557. [PMID: 33939268 PMCID: PMC8189214 DOI: 10.1111/irv.12860] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/28/2021] [Indexed: 01/12/2023] Open
Affiliation(s)
- Emily R Robie
- Division of Infectious Diseases, School of Medicine, Duke University, Durham, NC, USA.,Duke Global Health Institute, Duke University, Durham, NC, USA
| | - Anfal Abdelgadir
- Division of Infectious Diseases, School of Medicine, Duke University, Durham, NC, USA.,Duke Global Health Institute, Duke University, Durham, NC, USA
| | - Raquel A Binder
- Division of Infectious Diseases, School of Medicine, Duke University, Durham, NC, USA.,Duke Global Health Institute, Duke University, Durham, NC, USA
| | - Gregory C Gray
- Division of Infectious Diseases, School of Medicine, Duke University, Durham, NC, USA.,Duke Global Health Institute, Duke University, Durham, NC, USA.,Global Health Research Center, Duke Kunshan University, Kunshan, China.,Program in Emerging Infectious Diseases, Duke-NUS Medical School, Singapore, Singapore
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