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Vasei M, Jafari E, Falah Azad V, Safavi M, Sotoudeh M. Molecular Diagnosis of COVID-19; Biosafety and Pre-analytical Recommendations. IRANIAN JOURNAL OF PATHOLOGY 2023; 18:244-256. [PMID: 37942195 PMCID: PMC10628373 DOI: 10.30699/ijp.2023.1988405.3061] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/08/2023] [Accepted: 05/08/2023] [Indexed: 11/10/2023]
Abstract
From the beginning of the COVID-19 epidemic, clinical laboratories around the world have been involved with tests for detection of SARS-CoV-2. At present, RT-PCR (real-time reverse transcription polymerase chain reaction assay) is seen as the gold standard for identifying the virus. Many factors are involved in achieving the highest accuracy in this test, including parameters related to the pre-analysis stage. Having instructions on the type of sample, how to take the sample, and its storage and transportation help control the interfering factors at this stage. Studies have shown that pre-analytical factors might be the cause of the high SARS-CoV-2 test false-negative rates. Also, the safety of personnel in molecular laboratories is of utmost importance, and it requires strict guidelines to ensure the safety of exposed individuals and prevent the virus from spreading. Since the onset of the outbreak, various instructions and guidelines have been developed in this field by the institutions and the Ministry of Health of each country; these guidelines are seriously in need of integration and operation. In this study, we try to collect all the information and research done from the beginning of this pandemic in December 2019 - August 2022 concerning biosafety and protective measures, sample types, sampling methods, container, and storage solutions, sampling equipment, and sample storage and transportation for molecular testing of SARS-CoV-2.
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Affiliation(s)
- Mohammad Vasei
- Molecular Pathology and Cytogenetics Division, Pathology Department, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
- Cell-BasedTherapies Research Center, Digestive Disease Research Institute, Shari'ati Hospital, Tehran University of Medical Science, Tehran, Iran
| | - Elham Jafari
- Molecular Pathology and Cytogenetics Division, Pathology Department, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
- Pathology and Stem Cells Research Center, Kerman University of Medical Sciences, Kerman, Iran
| | - Vahid Falah Azad
- Molecular Pathology and Cytogenetics Division, Pathology Department, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Moeinadin Safavi
- Molecular Pathology and Cytogenetics Division, Pathology Department, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
| | - Maryam Sotoudeh
- Molecular Pathology and Cytogenetics Division, Pathology Department, Children's Medical Center, Tehran University of Medical Sciences, Tehran, Iran
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2
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Viloria Winnett A, Akana R, Shelby N, Davich H, Caldera S, Yamada T, Reyna JRB, Romano AE, Carter AM, Kim MK, Thomson M, Tognazzini C, Feaster M, Goh YY, Chew YC, Ismagilov RF. Extreme differences in SARS-CoV-2 viral loads among respiratory specimen types during presumed pre-infectious and infectious periods. PNAS NEXUS 2023; 2:pgad033. [PMID: 36926220 PMCID: PMC10013338 DOI: 10.1093/pnasnexus/pgad033] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Revised: 01/18/2023] [Accepted: 01/24/2023] [Indexed: 03/16/2023]
Abstract
SARS-CoV-2 viral-load measurements from a single-specimen type are used to establish diagnostic strategies, interpret clinical-trial results for vaccines and therapeutics, model viral transmission, and understand virus-host interactions. However, measurements from a single-specimen type are implicitly assumed to be representative of other specimen types. We quantified viral-load timecourses from individuals who began daily self-sampling of saliva, anterior-nares (nasal), and oropharyngeal (throat) swabs before or at the incidence of infection with the Omicron variant. Viral loads in different specimen types from the same person at the same timepoint exhibited extreme differences, up to 109 copies/mL. These differences were not due to variation in sample self-collection, which was consistent. For most individuals, longitudinal viral-load timecourses in different specimen types did not correlate. Throat-swab and saliva viral loads began to rise as many as 7 days earlier than nasal-swab viral loads in most individuals, leading to very low clinical sensitivity of nasal swabs during the first days of infection. Individuals frequently exhibited presumably infectious viral loads in one specimen type while viral loads were low or undetectable in other specimen types. Therefore, defining an individual as infectious based on assessment of a single-specimen type underestimates the infectious period, and overestimates the ability of that specimen type to detect infectious individuals. For diagnostic COVID-19 testing, these three single-specimen types have low clinical sensitivity, whereas a combined throat-nasal swab, and assays with high analytical sensitivity, was inferred to have significantly better clinical sensitivity to detect presumed pre-infectious and infectious individuals.
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Affiliation(s)
| | - Reid Akana
- California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
| | - Natasha Shelby
- California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
| | - Hannah Davich
- California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
| | - Saharai Caldera
- California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
| | - Taikun Yamada
- Pangea Laboratory LLC, 14762 Bentley Cir, Tustin, CA 92780, USA.,Zymo Research Corp., 17062 Murphy Ave, Irvine, CA 92614, USA
| | | | - Anna E Romano
- California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
| | - Alyssa M Carter
- California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
| | - Mi Kyung Kim
- California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
| | - Matt Thomson
- California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
| | - Colten Tognazzini
- Pasadena Public Health Department, 1845 N. Fair Oaks Ave, Pasadena, CA 91103, USA
| | - Matthew Feaster
- Pasadena Public Health Department, 1845 N. Fair Oaks Ave, Pasadena, CA 91103, USA
| | - Ying-Ying Goh
- Pasadena Public Health Department, 1845 N. Fair Oaks Ave, Pasadena, CA 91103, USA
| | - Yap Ching Chew
- Pangea Laboratory LLC, 14762 Bentley Cir, Tustin, CA 92780, USA.,Zymo Research Corp., 17062 Murphy Ave, Irvine, CA 92614, USA
| | - Rustem F Ismagilov
- California Institute of Technology, 1200 E. California Blvd, Pasadena, CA 91125, USA
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3
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Limitations of Molecular and Antigen Test Performance for SARS-CoV-2 in Symptomatic and Asymptomatic COVID-19 Contacts. J Clin Microbiol 2022; 60:e0018722. [PMID: 35730949 PMCID: PMC9297839 DOI: 10.1128/jcm.00187-22] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
COVID-19 has brought unprecedented attention to the crucial role of diagnostics in pandemic control. We compared severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) test performance by sample type and modality in close contacts of SARS-CoV-2 cases. Close contacts of SARS-CoV-2-positive individuals were enrolled after informed consent. Clinician-collected nasopharyngeal (NP) swabs in viral transport media (VTM) were tested with a routine clinical reference nucleic acid test (NAT) and PerkinElmer real-time reverse transcription-PCR (RT-PCR) assay; positive samples were tested for infectivity using a VeroE6TMPRSS2 cell culture model. Self-collected passive drool was also tested using the PerkinElmer RT-PCR assay. For the first 4 months of study, midturbinate swabs were tested using the BD Veritor rapid antigen test. Between 17 November 2020 and 1 October 2021, 235 close contacts of SARS-CoV-2 cases were recruited, including 95 with symptoms (82% symptomatic for ≤5 days) and 140 asymptomatic individuals. Reference NATs were positive for 53 (22.6%) participants; 24/50 (48%) were culture positive. PerkinElmer testing of NP and saliva samples identified an additional 28 (11.9%) SARS-CoV-2 cases who tested negative by reference NAT. Antigen tests performed for 99 close contacts showed 83% positive percent agreement (PPA) with reference NAT among early symptomatic persons, but 18% PPA in others; antigen tests in 8 of 11 (72.7%) culture-positive participants were positive. Contacts of SARS-CoV-2 cases may be falsely negative early after contact, but more sensitive platforms may identify these cases. Repeat or serial SARS-CoV-2 testing with both antigen and molecular assays may be warranted for individuals with high pretest probability for infection.
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Abstract
Though rapid antigen tests have historically problematic performance characteristics for the diagnosis of respiratory viral infections such as influenza, they have attained an unprecedented level of use in the context of the COVID-19 pandemic. Ease of use and scalability of rapid antigen tests has facilitated a democratization and scale of testing beyond anything reasonably achievable by traditional laboratory-based testing. In this chapter, we discuss the performance characteristics of rapid antigen testing for SARS-CoV-2 detection and their application to non-traditional uses beyond clinical diagnostic testing.
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Improving the specificity of nucleic acid detection with endonuclease-actuated degradation. Commun Biol 2022; 5:290. [PMID: 35361863 PMCID: PMC8971390 DOI: 10.1038/s42003-022-03242-x] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2021] [Accepted: 03/07/2022] [Indexed: 11/08/2022] Open
Abstract
Nucleic acid detection is essential for numerous biomedical applications, but often requires complex protocols and/or suffers false-positive readouts. Here, we describe SENTINEL, an approach that combines isothermal amplification with a sequence-specific degradation method to detect nucleic acids with high sensitivity and sequence-specificity. Target single-stranded RNA or double-stranded DNA molecules are amplified by loop-mediated isothermal amplification (LAMP) and subsequently degraded by the combined action of lambda exonuclease and a sequence-specific DNA endonuclease (e.g., Cas9). By combining the sensitivity of LAMP with the precision of DNA endonucleases, the protocol achieves attomolar limits of detection while differentiating between sequences that differ by only one or two base pairs. The protocol requires less than an hour to complete using a 65 °C heat block and fluorometer, and detects SARS-CoV-2 virus particles in human saliva and nasopharyngeal swabs with high sensitivity.
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Utama R, Hapsari R, Puspitasari I, Sari D, Hendrianingtyas M, Nurainy N. Self-collected gargle specimen as a patient-friendly sample collection method for COVID-19 diagnosis in a population context. Sci Rep 2022; 12:3706. [PMID: 35260654 PMCID: PMC8904449 DOI: 10.1038/s41598-022-07690-7] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2021] [Accepted: 02/21/2022] [Indexed: 12/23/2022] Open
Abstract
Scaling up SARS-CoV-2 testing and tracing continues to be plagued with the limitation of the sample collection method, which requires trained healthcare workers to perform and causes discomfort to the patients. In response, we assessed the performance and user preference of gargle specimens for qRT-PCR-based detection of SARS-CoV-2 in Indonesia. Inpatients who had recently been diagnosed with COVID-19 and outpatients who were about to perform qRT-PCR testing were asked to provide nasopharyngeal and oropharyngeal (NPOP) swabs and self-collected gargle specimens. We demonstrated that self-collected gargle specimens can be an alternative specimen to detect SARS-CoV-2 and the viral RNA remained stable for 31 days at room temperature storage. The developed method was validated for use on multiple RNA extraction kits and commercially available COVID-19 RT-PCR kits. Our developed method achieved a sensitivity of 91.38% when compared to paired NPOP swab specimens (Ct < 35), with 97.10% of patients preferring the self-collected gargle method.
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Affiliation(s)
- Revata Utama
- Nusantics, PT. Riset Nusantara Genetika, Jakarta, Indonesia
| | - Rebriarina Hapsari
- Faculty of Medicine, Universitas Diponegoro, Semarang, Indonesia.,Diponegoro National Hospital, Semarang, Indonesia
| | - Iva Puspitasari
- Faculty of Medicine, Universitas Diponegoro, Semarang, Indonesia.,Central General Hospital Dr. Kariadi, Semarang, Indonesia
| | - Desvita Sari
- Faculty of Medicine, Universitas Diponegoro, Semarang, Indonesia.,Central General Hospital Dr. Kariadi, Semarang, Indonesia
| | - Meita Hendrianingtyas
- Faculty of Medicine, Universitas Diponegoro, Semarang, Indonesia.,Diponegoro National Hospital, Semarang, Indonesia
| | - Neni Nurainy
- PT. Bio Farma, Development of Translational Biopharmaceutical Products Division, Bandung, Indonesia.
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Savela ES, Viloria Winnett A, Romano AE, Porter MK, Shelby N, Akana R, Ji J, Cooper MM, Schlenker NW, Reyes JA, Carter AM, Barlow JT, Tognazzini C, Feaster M, Goh YY, Ismagilov RF. Quantitative SARS-CoV-2 Viral-Load Curves in Paired Saliva Samples and Nasal Swabs Inform Appropriate Respiratory Sampling Site and Analytical Test Sensitivity Required for Earliest Viral Detection. J Clin Microbiol 2022; 60:e0178521. [PMID: 34911366 PMCID: PMC8849374 DOI: 10.1128/jcm.01785-21] [Citation(s) in RCA: 49] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2021] [Accepted: 12/10/2021] [Indexed: 11/20/2022] Open
Abstract
Early detection of SARS-CoV-2 infection is critical to reduce asymptomatic and presymptomatic transmission, curb the spread of variants, and maximize treatment efficacy. Low-analytical-sensitivity nasal-swab testing is commonly used for surveillance and symptomatic testing, but the ability of these tests to detect the earliest stages of infection has not been established. In this study, conducted between September 2020 and June 2021 in the greater Los Angeles County, California, area, initially SARS-CoV-2-negative household contacts of individuals diagnosed with COVID-19 prospectively self-collected paired anterior-nares nasal-swab and saliva samples twice daily for viral-load quantification by high-sensitivity reverse-transcription quantitative PCR (RT-qPCR) and digital-RT-PCR assays. We captured viral-load profiles from the incidence of infection for seven individuals and compared diagnostic sensitivities between respiratory sites. Among unvaccinated persons, testing saliva with a high-analytical-sensitivity assay detected infection up to 4.5 days before viral loads in nasal swabs reached concentrations detectable by low-analytical-sensitivity nasal-swab tests. For most participants, nasal swabs reached higher peak viral loads than saliva but were undetectable or at lower loads during the first few days of infection. High-analytical-sensitivity saliva testing was most reliable for earliest detection. Our study illustrates the value of acquiring early (within hours after a negative high-sensitivity test) viral-load profiles to guide the appropriate analytical sensitivity and respiratory site for detecting earliest infections. Such data are challenging to acquire but critical to designing optimal testing strategies with emerging variants in the current pandemic and to respond to future viral pandemics.
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Affiliation(s)
- Emily S. Savela
- California Institute of Technology, Pasadena, California, USA
| | | | - Anna E. Romano
- California Institute of Technology, Pasadena, California, USA
| | | | - Natasha Shelby
- California Institute of Technology, Pasadena, California, USA
| | - Reid Akana
- California Institute of Technology, Pasadena, California, USA
| | - Jenny Ji
- California Institute of Technology, Pasadena, California, USA
| | | | | | | | | | - Jacob T. Barlow
- California Institute of Technology, Pasadena, California, USA
| | - Colten Tognazzini
- City of Pasadena Public Health Department, Pasadena, California, USA
| | - Matthew Feaster
- City of Pasadena Public Health Department, Pasadena, California, USA
| | - Ying-Ying Goh
- City of Pasadena Public Health Department, Pasadena, California, USA
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8
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Robinson ML, Mirza A, Gallagher N, Boudreau A, Garcia L, Yu T, Norton J, Luo CH, Conte A, Zhou R, Kafka K, Hardick J, McManus DD, Gibson LL, Pekosz A, Mostafa H, Manabe YC. Limitations of molecular and antigen test performance for SARS-CoV-2 in symptomatic and asymptomatic COVID-19 contacts. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2022. [PMID: 35169814 DOI: 10.1101/2022.02.05.22270481] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
OBJECTIVES COVID-19 has brought unprecedented attention to the crucial role of diagnostics in pandemic control. We compared SARS-CoV-2 test performance by sample type and modality in close contacts of SARS-CoV-2 cases. METHODS Close contacts of SARS-CoV-2 positive individuals were enrolled after informed consent. Clinician-collected nasopharyngeal (NP) swabs in viral transport media (VTM) were tested with a nucleic acid test (NAT). NP VTM and self-collected passive drool were tested using the PerkinElmer real-time reverse transcription PCR (RT-PCR) assay. For the first 4 months of study, mid-turbinate swabs were tested using the BD Veritor rapid antigen test. NAT positive NP samples were tested for infectivity using a VeroE6TMPRSS2 cell culture model. RESULTS Between November 17, 2020, and October 1, 2021, 235 close contacts of SARS-CoV-2 cases were recruited, including 95 with symptoms (82% symptomatic for < 5 days) and 140 asymptomatic individuals. NP swab reference tests were positive for 53 (22.6%) participants; 24/50 (48%) were culture positive. PerkinElmer testing of NP and saliva samples identified an additional 28 (11.9%) SARS-CoV-2 cases who tested negative by clinical NAT. Antigen tests performed for 99 close contacts showed 83% positive percent agreement (PPA) with reference NAT among early symptomatic persons, but 18% PPA in others; antigen tests in 8 of 11 (72.7%) culture-positive participants were positive. CONCLUSIONS Contacts of SARS-CoV-2 cases may be falsely negative early after contact, which more sensitive platforms may identify. Repeat or serial SARS-CoV-2 testing with both antigen and molecular assays may be warranted for individuals with high pretest probability for infection.
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Kazmer ST, Hartel G, Robinson H, Richards RS, Yan K, van Hal SJ, Chan R, Hind A, Bradley D, Zieschang F, Rawle DJ, Le TT, Reid DW, Suhrbier A, Hill MM. Pathophysiological Response to SARS-CoV-2 Infection Detected by Infrared Spectroscopy Enables Rapid and Robust Saliva Screening for COVID-19. Biomedicines 2022; 10:biomedicines10020351. [PMID: 35203562 PMCID: PMC8962262 DOI: 10.3390/biomedicines10020351] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2021] [Revised: 01/10/2022] [Accepted: 01/26/2022] [Indexed: 02/04/2023] Open
Abstract
Fourier transform infrared (FTIR) spectroscopy provides a (bio)chemical snapshot of the sample, and was recently used in proof-of-concept cohort studies for COVID-19 saliva screening. However, the biological basis of the proposed technology has not been established. To investigate underlying pathophysiology, we conducted controlled infection experiments on Vero E6 cells in vitro and K18-hACE2 mice in vivo. Potentially infectious culture supernatant or mouse oral lavage samples were treated with ethanol or 75% (v/v) Trizol for attenuated total reflectance (ATR)-FTIR spectroscopy and proteomics, or RT-PCR, respectively. Controlled infection with UV-inactivated SARS-CoV-2 elicited strong biochemical changes in culture supernatant/oral lavage despite a lack of viral replication, determined by RT-PCR or a cell culture infectious dose 50% assay. Nevertheless, SARS-CoV-2 infection induced additional FTIR signals over UV-inactivated SARS-CoV-2 infection in both cell and mouse models, which correspond to aggregated proteins and RNA. Proteomics of mouse oral lavage revealed increased secretion of kallikreins and immune modulatory proteins. Next, we collected saliva from a cohort of human participants (n = 104) and developed a predictive model for COVID-19 using partial least squares discriminant analysis. While high sensitivity of 93.48% was achieved through leave-one-out cross-validation, COVID-19 patients testing negative on follow-up on the day of saliva sampling using RT-PCR was poorly predicted in this model. Importantly, COVID-19 vaccination did not lead to the misclassification of COVID-19 negatives. Finally, meta-analysis revealed that SARS-CoV-2 induced increases in the amide II band in all arms of this study and in recently published cohort studies, indicative of altered β-sheet structures in secreted proteins. In conclusion, this study reveals a consistent secretory pathophysiological response to SARS-CoV-2, as well as a simple, robust method for COVID-19 saliva screening using ATR-FTIR.
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Affiliation(s)
- Seth T. Kazmer
- Precision & Systems Biomedicine Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD 4006, Australia; (S.T.K.); (H.R.); (R.S.R.)
| | - Gunter Hartel
- Biostatistics Unit, QIMR Berghofer Medical Research Institute, Herston, QLD 4006, Australia;
| | - Harley Robinson
- Precision & Systems Biomedicine Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD 4006, Australia; (S.T.K.); (H.R.); (R.S.R.)
| | - Renee S. Richards
- Precision & Systems Biomedicine Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD 4006, Australia; (S.T.K.); (H.R.); (R.S.R.)
| | - Kexin Yan
- Inflammation Biology Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD 4006, Australia; (K.Y.); (D.J.R.); (T.T.L.); (A.S.)
| | - Sebastiaan J. van Hal
- New South Wales Health Pathology-Royal Prince Alfred Hospital, Camperdown, NSW 2050, Australia; (S.J.v.H.); (R.C.)
| | - Raymond Chan
- New South Wales Health Pathology-Royal Prince Alfred Hospital, Camperdown, NSW 2050, Australia; (S.J.v.H.); (R.C.)
| | - Andrew Hind
- Agilent Technologies Australia, Mulgrave, VIC 3170, Australia; (A.H.); (D.B.); (F.Z.)
| | - David Bradley
- Agilent Technologies Australia, Mulgrave, VIC 3170, Australia; (A.H.); (D.B.); (F.Z.)
| | - Fabian Zieschang
- Agilent Technologies Australia, Mulgrave, VIC 3170, Australia; (A.H.); (D.B.); (F.Z.)
| | - Daniel J. Rawle
- Inflammation Biology Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD 4006, Australia; (K.Y.); (D.J.R.); (T.T.L.); (A.S.)
| | - Thuy T. Le
- Inflammation Biology Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD 4006, Australia; (K.Y.); (D.J.R.); (T.T.L.); (A.S.)
| | - David W. Reid
- Lung Inflammation & Infection Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD 4006, Australia;
- The Prince Charles Hospital, Chermside, QLD 4032, Australia
| | - Andreas Suhrbier
- Inflammation Biology Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD 4006, Australia; (K.Y.); (D.J.R.); (T.T.L.); (A.S.)
- Australian Infectious Disease Research Centre, GVN Centre of Excellence, Brisbane, QLD 4029, Australia
| | - Michelle M. Hill
- Precision & Systems Biomedicine Laboratory, QIMR Berghofer Medical Research Institute, Herston, QLD 4006, Australia; (S.T.K.); (H.R.); (R.S.R.)
- UQ Centre for Clinical Research, Faculty of Medicine, The University of Queensland, Herston, QLD 4006, Australia
- Correspondence:
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10
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Choi SJ, Jung J, Kim ES, Kim HB, Park JS, Park KU, Lee H, Lee E, Choe PG, Kim JY, Lee EJ, Song KH. Diagnostic Performance, Stability, and Usability of Self-Collected Combo Swabs and Saliva for Coronavirus Disease 2019 Diagnosis: A Case-Control Study. Infect Chemother 2022; 54:517-528. [PMID: 36196610 PMCID: PMC9533156 DOI: 10.3947/ic.2022.0081] [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: 06/04/2022] [Accepted: 08/30/2022] [Indexed: 11/24/2022] Open
Abstract
Background Self-sampling procedures to detect severe acute respiratory syndrome coronavirus 2 is important for patients who have difficulty visiting the hospital and may decrease the burden for health care workers (HCWs). The objective of this study was to evaluate the diagnostic performance, stability and usability of self-collected nasal and oral combo swabs and saliva specimens. Materials and Methods We conducted a case-control study with 50 patients with coronavirus disease 2019 (COVID-19) and 50 healthy volunteers from March, 2021 to June, 2021. We performed real-time reverse-transcription polymerase chain reaction to compare the diagnostic performance of self-collected specimens using positive percent agreements (PPAs). Results The PPAs between self-collected and HCW-collected specimens were 77.3 - 81.0% and 80.5 -86.7% for the combo swabs and saliva specimens, respectively. The PPAs increased to 88.9 - 89.2% and 81.2 - 82.1% with a cycle threshold value ≤30. Conclusion The diagnostic performance of self sampling was comparable to that of HCW sampling in patients with high viral loads and may thus assist in the early diagnosis of COVID-19.
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Affiliation(s)
- Seong Jin Choi
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Jongtak Jung
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
- Department of Internal Medicine, Soonchunhyang University Seoul Hospital, Soonchunhyang University College of Medicine, Seoul, Korea
| | - Eu Suk Kim
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Hong Bin Kim
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Jeong Su Park
- Department of Laboratory Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Kyoung Un Park
- Department of Laboratory Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Hyunju Lee
- Department of Pediatrics, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
| | - Eunyoung Lee
- Department of Internal Medicine, Boramae Medical Center, Seoul National University College of Medicine, Seoul, Korea
| | - Pyoeng Gyun Choe
- Department of Internal Medicine, Seoul National University Hospital, Seoul National University College of Medicine, Seoul, Korea
| | - Ji-Yeon Kim
- Department of Internal Medicine, Seongnam Citizens Medical Center, Seongnam, Korea
| | - Eun Joo Lee
- Department of Pediatrics, Seongnam Citizens Medical Center, Seongnam, Korea
| | - Kyoung-Ho Song
- Department of Internal Medicine, Seoul National University Bundang Hospital, Seoul National University College of Medicine, Seongnam, Korea
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11
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Demko ZO, Antar AAR, Blair PW, Lambrou AS, Yu T, Brown D, Walch SN, Armstrong DT, Mostafa HH, Keruly JC, Thomas DL, Manabe YC, Mehta SH. Clustering of SARS-CoV-2 Infections in Households of Patients Diagnosed in the Outpatient Setting in Baltimore, Maryland. Open Forum Infect Dis 2021; 8:ofab121. [PMID: 34796248 PMCID: PMC7989179 DOI: 10.1093/ofid/ofab121] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Accepted: 03/09/2021] [Indexed: 11/16/2022] Open
Abstract
In an outpatient cohort in Maryland, clustering of severe acute respiratory
syndrome coronavirus 2 (SARS-CoV-2) positivity within households was high, with
76% of 74 households reporting at least 1 other symptomatic person and 66%
reporting another person who tested SARS-CoV-2 positive. SARS-CoV-2 positivity
among household members was associated with larger household size and bedroom
sharing.
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Affiliation(s)
- Zoe O Demko
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Annukka A R Antar
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Paul W Blair
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA.,Henry M. Jackson Foundation, Bethesda, Maryland, USA
| | - Anastasia S Lambrou
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Tong Yu
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Diane Brown
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Samantha N Walch
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Derek T Armstrong
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Heba H Mostafa
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jeanne C Keruly
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - David L Thomas
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Yukari C Manabe
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Shruti H Mehta
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
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12
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De Marinis Y, Pesola AK, Söderlund Strand A, Norman A, Pernow G, Aldén M, Yang R, Rasmussen M. Detection of SARS-CoV-2 by rapid antigen tests on saliva in hospitalized patients with COVID-19. Infect Ecol Epidemiol 2021; 11:1993535. [PMID: 34745449 PMCID: PMC8567870 DOI: 10.1080/20008686.2021.1993535] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
Background The COVID-19 pandemic presents great challenges on transmission prevention, and rapid diagnosis is essential to reduce the disease spread. Various diagnostic methods are available to identify an ongoing infection by nasopharyngeal (NPH) swab sampling. However, the procedure requires handling by health care professionals, and therefore limits the application in household and community settings. Objectives In this study, we aimed to determine if the detection of SARS-CoV-2 can be performed alternatively on saliva specimens by rapid antigen test. Study Design Saliva and NPH specimens were collected from 44 patients with confirmed COVID-19. To assess the diagnostic accuracy of point-of-care SARS-CoV-2 rapid antigen test on saliva specimens, we compared the performance of four test products. Results RT-qPCR was performed and NPH and saliva sampling had similar Ct values, which associated with disease duration. All four antigen tests showed similar trend in detecting SARS-CoV-2 in saliva, but with variation in the ability to detect positive cases. The rapid antigen test with the best performance could detect up to 67% of the positive cases with Ct values lower than 25, and disease duration shorter than 10 days. Conclusion Our study therefore supports saliva testing as an alternative diagnostic procedure to NPH testing, and that rapid antigen test on saliva provides a potential complement to PCR test to meet increasing screening demand.
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Affiliation(s)
- Yang De Marinis
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden.,School of Control Science and Engineering, Shandong University, Jinan, China.,Department of Endocrinology and Metabolism, Division of Life Sciences of Medicine, University of Science and Technology of China, Hefei, China
| | | | | | - Astrid Norman
- Division of Infection Medicine, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Gustav Pernow
- Division of Infection Medicine, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
| | - Markus Aldén
- Department of Clinical Sciences Malmö, Lund University, Malmö, Sweden
| | - Runtao Yang
- School of Mechanical, Electrical and Information Engineering, Shandong University, Weihai, China
| | - Magnus Rasmussen
- Division of Infection Medicine, Department of Clinical Sciences Lund, Lund University, Lund, Sweden
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13
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Savela ES, Winnett A, Romano AE, Porter MK, Shelby N, Akana R, Ji J, Cooper MM, Schlenker NW, Reyes JA, Carter AM, Barlow JT, Tognazzini C, Feaster M, Goh YY, Ismagilov RF. Quantitative SARS-CoV-2 viral-load curves in paired saliva and nasal swabs inform appropriate respiratory sampling site and analytical test sensitivity required for earliest viral detection. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2021:2021.04.02.21254771. [PMID: 33851180 PMCID: PMC8043477 DOI: 10.1101/2021.04.02.21254771] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Early detection of SARS-CoV-2 infection is critical to reduce asymptomatic and pre-symptomatic transmission, curb the spread of variants by travelers, and maximize treatment efficacy. Low-sensitivity nasal-swab testing (antigen and some nucleic-acid-amplification tests) is commonly used for surveillance and symptomatic testing, but the ability of low-sensitivity nasal-swab tests to detect the earliest stages of infection has not been established. In this case-ascertained study, initially-SARS-CoV-2-negative household contacts of individuals diagnosed with COVID-19 prospectively self-collected paired anterior-nares nasal-swab and saliva samples twice daily for viral-load quantification by high-sensitivity RT-qPCR and digital-RT-PCR assays. We captured viral-load profiles from the incidence of infection for seven individuals and compared diagnostic sensitivities between respiratory sites. Among unvaccinated persons, high-sensitivity saliva testing detected infection up to 4.5 days before viral loads in nasal swabs reached the limit of detection of low-sensitivity nasal-swab tests. For most participants, nasal swabs reached higher peak viral loads than saliva, but were undetectable or at lower loads during the first few days of infection. High-sensitivity saliva testing was most reliable for earliest detection. Our study illustrates the value of acquiring early (within hours after a negative high-sensitivity test) viral-load profiles to guide the appropriate analytical sensitivity and respiratory site for detecting earliest infections. Such data are challenging to acquire but critical to design optimal testing strategies in the current pandemic and will be required for responding to future viral pandemics. As new variants and viruses emerge, up-to-date data on viral kinetics are necessary to adjust testing strategies for reliable early detection of infections.
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Affiliation(s)
- Emily S. Savela
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Alexander Winnett
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Anna E. Romano
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Michael K. Porter
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Natasha Shelby
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Reid Akana
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Jenny Ji
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Matthew M. Cooper
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Noah W. Schlenker
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Jessica A. Reyes
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Alyssa M. Carter
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Jacob T. Barlow
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
| | - Colten Tognazzini
- City of Pasadena Public Health Department, 1845 N. Fair Oaks Ave., Pasadena, CA, USA 91103
| | - Matthew Feaster
- City of Pasadena Public Health Department, 1845 N. Fair Oaks Ave., Pasadena, CA, USA 91103
| | - Ying-Ying Goh
- City of Pasadena Public Health Department, 1845 N. Fair Oaks Ave., Pasadena, CA, USA 91103
| | - Rustem F. Ismagilov
- California Institute of Technology, 1200 E. California Blvd., Pasadena, CA, USA 91125
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14
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Borghi E, Massa V, Zuccotti G, Wyllie AL. Testing Saliva to Reveal the Submerged Cases of the COVID-19 Iceberg. Front Microbiol 2021; 12:721635. [PMID: 34322114 PMCID: PMC8312273 DOI: 10.3389/fmicb.2021.721635] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 06/22/2021] [Indexed: 01/10/2023] Open
Affiliation(s)
- Elisa Borghi
- Department of Health Sciences, Università degli Studi di Milano, Milan, Italy
| | - Valentina Massa
- Department of Health Sciences, Università degli Studi di Milano, Milan, Italy
| | - Gianvincenzo Zuccotti
- Department of Biomedical and Clinical Sciences “L. Sacco”, Università degli Studi di Milano, Milan, Italy
| | - Anne L. Wyllie
- Department of Epidemiology of Microbial Diseases, Yale School of Public Health, New Haven, CT, United States
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15
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Antar AAR, Yu T, Pisanic N, Azamfirei R, Tornheim JA, Brown DM, Kruczynski K, Hardick JP, Sewell T, Jang M, Church T, Walch SN, Reuland C, Bachu VS, Littlefield K, Park HS, Ursin RL, Ganesan A, Kusemiju O, Barnaba B, Charles C, Prizzi M, Johnstone JR, Payton C, Dai W, Fuchs J, Massaccesi G, Armstrong DT, Townsend JL, Keller SC, Demko ZO, Hu C, Wang MC, Sauer LM, Mostafa HH, Keruly JC, Mehta SH, Klein SL, Cox AL, Pekosz A, Heaney CD, Thomas DL, Blair PW, Manabe YC. Delayed Rise of Oral Fluid Antibodies, Elevated BMI, and Absence of Early Fever Correlate With Longer Time to SARS-CoV-2 RNA Clearance in a Longitudinally Sampled Cohort of COVID-19 Outpatients. Open Forum Infect Dis 2021; 8:ofab195. [PMID: 34095338 PMCID: PMC8083254 DOI: 10.1093/ofid/ofab195] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2021] [Accepted: 04/13/2021] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Sustained molecular detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) RNA in the upper respiratory tract (URT) in mild to moderate coronavirus disease 2019 (COVID-19) is common. We sought to identify host and immune determinants of prolonged SARS-CoV-2 RNA detection. METHODS Ninety-five symptomatic outpatients self-collected midturbinate nasal, oropharyngeal (OP), and gingival crevicular fluid (oral fluid) samples at home and in a research clinic a median of 6 times over 1-3 months. Samples were tested for viral RNA, virus culture, and SARS-CoV-2 and other human coronavirus antibodies, and associations were estimated using Cox proportional hazards models. RESULTS Viral RNA clearance, as measured by SARS-CoV-2 reverse transcription polymerase chain reaction (RT-PCR), in 507 URT samples occurred a median (interquartile range) 33.5 (17-63.5) days post-symptom onset. Sixteen nasal-OP samples collected 2-11 days post-symptom onset were virus culture positive out of 183 RT-PCR-positive samples tested. All participants but 1 with positive virus culture were negative for concomitant oral fluid anti-SARS-CoV-2 antibodies. The mean time to first antibody detection in oral fluid was 8-13 days post-symptom onset. A longer time to first detection of oral fluid anti-SARS-CoV-2 S antibodies (adjusted hazard ratio [aHR], 0.96; 95% CI, 0.92-0.99; P = .020) and body mass index (BMI) ≥25 kg/m2 (aHR, 0.37; 95% CI, 0.18-0.78; P = .009) were independently associated with a longer time to SARS-CoV-2 viral RNA clearance. Fever as 1 of first 3 COVID-19 symptoms correlated with shorter time to viral RNA clearance (aHR, 2.06; 95% CI, 1.02-4.18; P = .044). CONCLUSIONS We demonstrate that delayed rise of oral fluid SARS-CoV-2-specific antibodies, elevated BMI, and absence of early fever are independently associated with delayed URT viral RNA clearance.
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Affiliation(s)
- Annukka A R Antar
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Tong Yu
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Nora Pisanic
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Razvan Azamfirei
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jeffrey A Tornheim
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Diane M Brown
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Kate Kruczynski
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Justin P Hardick
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Thelio Sewell
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Minyoung Jang
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Taylor Church
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Samantha N Walch
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Carolyn Reuland
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Vismaya S Bachu
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Kirsten Littlefield
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Han-Sol Park
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Rebecca L Ursin
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Abhinaya Ganesan
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Oyinkansola Kusemiju
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Brittany Barnaba
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Curtisha Charles
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Michelle Prizzi
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jaylynn R Johnstone
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Christine Payton
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Weiwei Dai
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Joelle Fuchs
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Guido Massaccesi
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Derek T Armstrong
- Department of Pathology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Jennifer L Townsend
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Sara C Keller
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Zoe O Demko
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Chen Hu
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Mei-Cheng Wang
- Department of Biostatistics, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Lauren M Sauer
- Department of Emergency Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Heba H Mostafa
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Jeanne C Keruly
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Shruti H Mehta
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Sabra L Klein
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
- Department of Biochemistry and Molecular Biology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Andrea L Cox
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
- Department of Oncology, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Andrew Pekosz
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - Christopher D Heaney
- Department of Environmental Health and Engineering, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
- Department of Epidemiology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
- Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
| | - David L Thomas
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Paul W Blair
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Yukari C Manabe
- Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- W. Harry Feinstone Department of Molecular Microbiology and Immunology, Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland, USA
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