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1.
J Infect Dis ; 225(5): 768-776, 2022 03 02.
Article in English | MEDLINE | ID: covidwho-1722480

ABSTRACT

BACKGROUND: We determined the burden of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in air and on surfaces in rooms of patients hospitalized with coronavirus disease 2019 (COVID-19) and investigated patient characteristics associated with SARS-CoV-2 environmental contamination. METHODS: Nasopharyngeal swabs, surface, and air samples were collected from the rooms of 78 inpatients with COVID-19 at 6 acute care hospitals in Toronto from March to May 2020. Samples were tested for SARS-CoV-2 ribonucleic acid (RNA), cultured to determine potential infectivity, and whole viral genomes were sequenced. Association between patient factors and detection of SARS-CoV-2 RNA in surface samples were investigated. RESULTS: Severe acute respiratory syndrome coronavirus 2 RNA was detected from surfaces (125 of 474 samples; 42 of 78 patients) and air (3 of 146 samples; 3 of 45 patients); 17% (6 of 36) of surface samples from 3 patients yielded viable virus. Viral sequences from nasopharyngeal and surface samples clustered by patient. Multivariable analysis indicated hypoxia at admission, polymerase chain reaction-positive nasopharyngeal swab (cycle threshold of ≤30) on or after surface sampling date, higher Charlson comorbidity score, and shorter time from onset of illness to sampling date were significantly associated with detection of SARS-CoV-2 RNA in surface samples. CONCLUSIONS: The infrequent recovery of infectious SARS-CoV-2 virus from the environment suggests that the risk to healthcare workers from air and near-patient surfaces in acute care hospital wards is likely limited.


Subject(s)
COVID-19 , Nasopharynx/virology , Respiratory Aerosols and Droplets , SARS-CoV-2/isolation & purification , Adult , Aged , Air Microbiology , COVID-19/epidemiology , COVID-19/prevention & control , COVID-19/transmission , COVID-19 Nucleic Acid Testing , Canada/epidemiology , Environmental Exposure , Health Personnel , Humans , Inpatients , Middle Aged , Pandemics/prevention & control , SARS-CoV-2/genetics
2.
Nano Lett ; 21(12): 5209-5216, 2021 06 23.
Article in English | MEDLINE | ID: covidwho-1263457

ABSTRACT

The ability to rapidly diagnose, track, and disseminate information for SARS-CoV-2 is critical to minimize its spread. Here, we engineered a portable smartphone-based quantum barcode serological assay device for real-time surveillance of patients infected with SARS-CoV-2. Our device achieved a clinical sensitivity of 90% and specificity of 100% for SARS-CoV-2, as compared to 34% and 100%, respectively, for lateral flow assays in a head-to-head comparison. The lateral flow assay misdiagnosed ∼2 out of 3 SARS-CoV-2 positive patients. Our quantum dot barcode device has ∼3 times greater clinical sensitivity because it is ∼140 times more analytically sensitive than lateral flow assays. Our device can diagnose SARS-CoV-2 at different sampling dates and infectious severity. We developed a databasing app to provide instantaneous results to inform patients, physicians, and public health agencies. This assay and device enable real-time surveillance of SARS-CoV-2 seroprevalence and potential immunity.


Subject(s)
COVID-19 , Quantum Dots , Humans , Immunoassay , SARS-CoV-2 , Sensitivity and Specificity , Seroepidemiologic Studies , Smartphone
3.
Nat Commun ; 12(1): 1806, 2021 03 22.
Article in English | MEDLINE | ID: covidwho-1146643

ABSTRACT

Better diagnostic tools are needed to combat the ongoing COVID-19 pandemic. Here, to meet this urgent demand, we report a homogeneous immunoassay to detect IgG antibodies against SARS-CoV-2. This serological assay, called SATiN, is based on a tri-part Nanoluciferase (tNLuc) approach, in which the spike protein of SARS-CoV-2 and protein G, fused respectively to two different tNLuc tags, are used as antibody probes. Target engagement of the probes allows reconstitution of a functional luciferase in the presence of the third tNLuc component. The assay is performed directly in the liquid phase of patient sera and enables rapid, quantitative and low-cost detection. We show that SATiN has a similar sensitivity to ELISA, and its readouts are consistent with various neutralizing antibody assays. This proof-of-principle study suggests potential applications in diagnostics, as well as disease and vaccination management.


Subject(s)
Antibodies, Viral/blood , COVID-19 Testing/methods , COVID-19/diagnosis , Immunoassay/methods , Luciferases/metabolism , SARS-CoV-2/immunology , SARS-CoV-2/isolation & purification , Antibodies, Neutralizing/blood , Antibodies, Viral/immunology , COVID-19/blood , COVID-19/virology , Enzyme-Linked Immunosorbent Assay , HEK293 Cells , Humans , Immunoglobulin G/blood , Immunoglobulin M/blood , Spike Glycoprotein, Coronavirus/immunology
4.
Infect Control Hosp Epidemiol ; 42(8): 1001-1003, 2021 08.
Article in English | MEDLINE | ID: covidwho-977236

ABSTRACT

To compare sensitivity of specimens for COVID-19 diagnosis, we tested 151 nasopharyngeal/midturbinate swab pairs from 117 COVID-19 inpatients using reverse-transcriptase polymerase chain reaction (RT-PCR). Sensitivity was 94% for nasopharyngeal and 75% for midturbinate swabs (P = .0001). In 88 nasopharyngeal/midturbinate pairs with matched saliva, sensitivity was 86% for nasopharyngeal swabs and 88% for combined midturbinate swabs/saliva.


Subject(s)
COVID-19 , SARS-CoV-2 , COVID-19 Testing , Humans , Nasopharynx , Saliva , Specimen Handling
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