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3.
N Engl J Med ; 385(16): 1474-1484, 2021 10 14.
Article in English | MEDLINE | ID: covidwho-1612234

ABSTRACT

BACKGROUND: Despite the high efficacy of the BNT162b2 messenger RNA vaccine against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), rare breakthrough infections have been reported, including infections among health care workers. Data are needed to characterize these infections and define correlates of breakthrough and infectivity. METHODS: At the largest medical center in Israel, we identified breakthrough infections by performing extensive evaluations of health care workers who were symptomatic (including mild symptoms) or had known infection exposure. These evaluations included epidemiologic investigations, repeat reverse-transcriptase-polymerase-chain-reaction (RT-PCR) assays, antigen-detecting rapid diagnostic testing (Ag-RDT), serologic assays, and genomic sequencing. Correlates of breakthrough infection were assessed in a case-control analysis. We matched patients with breakthrough infection who had antibody titers obtained within a week before SARS-CoV-2 detection (peri-infection period) with four to five uninfected controls and used generalized estimating equations to predict the geometric mean titers among cases and controls and the ratio between the titers in the two groups. We also assessed the correlation between neutralizing antibody titers and N gene cycle threshold (Ct) values with respect to infectivity. RESULTS: Among 1497 fully vaccinated health care workers for whom RT-PCR data were available, 39 SARS-CoV-2 breakthrough infections were documented. Neutralizing antibody titers in case patients during the peri-infection period were lower than those in matched uninfected controls (case-to-control ratio, 0.361; 95% confidence interval, 0.165 to 0.787). Higher peri-infection neutralizing antibody titers were associated with lower infectivity (higher Ct values). Most breakthrough cases were mild or asymptomatic, although 19% had persistent symptoms (>6 weeks). The B.1.1.7 (alpha) variant was found in 85% of samples tested. A total of 74% of case patients had a high viral load (Ct value, <30) at some point during their infection; however, of these patients, only 17 (59%) had a positive result on concurrent Ag-RDT. No secondary infections were documented. CONCLUSIONS: Among fully vaccinated health care workers, the occurrence of breakthrough infections with SARS-CoV-2 was correlated with neutralizing antibody titers during the peri-infection period. Most breakthrough infections were mild or asymptomatic, although persistent symptoms did occur.


Subject(s)
COVID-19 Vaccines , COVID-19/epidemiology , Health Personnel/statistics & numerical data , Adult , Asymptomatic Diseases , COVID-19/diagnosis , COVID-19/prevention & control , COVID-19 Nucleic Acid Testing , Case-Control Studies , Female , Humans , Israel/epidemiology , Male , Middle Aged , Reverse Transcriptase Polymerase Chain Reaction , Treatment Failure
4.
BMC Public Health ; 22(1): 45, 2022 01 07.
Article in English | MEDLINE | ID: covidwho-1613232

ABSTRACT

BACKGROUND: Patients that arrive in the emergency department (ED) with COVID-19-like syndromes testing negative at the first RT-PCR represent a clinical challenge because of the lack of evidence about their management available in the literature. Our first aim was to quantify the proportion of patients testing negative at the first RT-PCR performed in our Emergency Department (ED) that were confirmed as having COVID-19 at the end of hospitalization by clinical judgment or by any subsequent microbiological testing. Secondly, we wanted to identify which variables that were available in the first assessment (ED variables) would have been useful in predicting patients, who at the end of the hospital stay were confirmed as having COVID-19 (false-negative at the first RT-PCR). METHODS: We retrospectively collected data of 115 negative patients from2020, March 1st to 2020, May 15th. Three experts revised patients' charts collecting information on the whole hospital stay and defining patients as COVID-19 or NOT-COVID-19. We compared ED variables in the two groups by univariate analysis and logistic regression. RESULTS: We classified 66 patients as COVID-19 and identified the other 49 as having a differential diagnosis (NOT-COVID), with a concordance between the three experts of 0.77 (95% confidence interval (95%CI) 0.66- 0.73). Only 15% of patients tested positive to a subsequent RT-PCR test, accounting for 25% of the clinically suspected. Having fever (odds ratio (OR) 3.32, (95%CI 0.97-12.31), p = 0.06), showing a typical pattern at the first lung ultrasound (OR 6.09, (95%CI 0.87-54.65), p = 0.08) or computed tomography scan (OR 4.18, (95%CI 1.11-17.86), p = 0.04) were associated with a higher probability of having COVID-19. CONCLUSIONS: In patients admitted to ED with COVID-19 symptoms and negative RT-PCR a comprehensive clinical evaluation integrated with lung ultrasound and computed tomography could help to detect COVID-19 patients with a false negative RT-PCR result.


Subject(s)
COVID-19 , Cohort Studies , Humans , Retrospective Studies , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2
5.
Braz J Infect Dis ; 25(5): 101630, 2021.
Article in English | MEDLINE | ID: covidwho-1604138

ABSTRACT

INTRODUCTION: In the current standard of care (SoC) RT-PCR method for COVID-19, the patient's swab was extracted in viral transport media (VTM). For the Panbio™ COVID-19 Ag Rapid Test, the patient swab is flushed out in extraction buffer, of which a small fraction is used for testing, leaving more than half the sample unused. This study was designed to show that RT-PCR results from the residual sample of the Panbio™ COVID-19 Ag Rapid Test (called Novel RT-PCR) are not worse than the SoC RT-PCR result. METHODS: The study was performed using (1) dilution series of five patient samples, and (2) 413 patient samples comparing SOC versus Novel RT-PCR results. RESULTS: For the dilution series samples, all tested positive by both methods. The bias between Ct values of Novel RT-PCR and SoC RT-PCR did not exceed 3.00 Ct using primers N1 and N2. A total of 413 COVID symptomatic patients seeking COVID testing were tested, of which 89 patients tested positive and 324 tested negative with SoC RT-PCR. In 324 patients who tested negative with SoC RT-PCR, 323 tested negative with Novel RT-PCR, and one (1) tested positive. Out of 89 who tested positive with SoC RT-PCR, 80 tested positive with the Novel RT-PCR, and nine patients showed a negative test result. The Overall Percent Agreement for the 413 valid patient sample pairs was 97.5 [95% CI 97 to 98]. CONCLUSION: The study demonstrated that the performance of the Novel RT-PCR method is acceptable compared to the SoC RT-PCR method and can be a useful tool to perform RT-PCR without the need for new swab collections.


Subject(s)
COVID-19 , Antigens, Viral , COVID-19 Testing , Humans , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2 , Sensitivity and Specificity
6.
Medicine (Baltimore) ; 100(47): e27980, 2021 Nov 24.
Article in English | MEDLINE | ID: covidwho-1604285

ABSTRACT

RATIONALE: Pulmonary fibrosis is an infamous sequela of coronavirus disease 2019 (COVID-19) pneumonia leading to long-lasting respiratory problems and activity limitations. Pulmonary rehabilitation is beneficial to improve the symptoms of lung fibrosis. We experienced a post-COVID-19 pulmonary fibrosis patient who received a structured exercise-based pulmonary rehabilitation program. PATIENT CONCERNS: This article presents a case of successful pulmonary rehabilitation of a patient with post-COVID-19 pulmonary fibrosis. The patient could not cut off the oxygen supplement even after a successful recovery from COVID-19. DIAGNOSIS: Diagnosis of COVID-19 was based on the reverse transcription-polymerase chain reaction (RT-PCR). Pulmonary fibrosis was diagnosed by patient's complaint, clinical appearance, and computed tomography (CT) on chest. INTERVENTION: The patient underwent ten sessions of exercise-based rehabilitation program according to Consensus Document on Pulmonary Rehabilitation in Korea, 2015. OUTCOME: On the 8th day, he could cut off the oxygen supplementation and complete the one-hour exercise without oxygen. He was discharged after completing the 10-session program without any activity limitations. LESSONS: Exercise-based pulmonary rehabilitation will help the post-COVID-19 pulmonary fibrosis patients. This case suggested the importance of pulmonary rehabilitation program to the post-COVID-19 pulmonary fibrosis patient.


Subject(s)
COVID-19/complications , Lung/diagnostic imaging , Pulmonary Fibrosis/rehabilitation , COVID-19/diagnosis , COVID-19 Testing , Humans , Lung/pathology , Male , Middle Aged , Oxygen , Pulmonary Fibrosis/diagnostic imaging , Pulmonary Fibrosis/etiology , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2 , Tomography, X-Ray Computed
7.
AIDS Rev ; 23(3): 153-163, 2021 06 03.
Article in English | MEDLINE | ID: covidwho-1579385

ABSTRACT

The novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly infectious RNA coronavirus responsible for the pandemic of the coronavirus disease 2019 (COVID-19). Recent advances in virology, epidemiology, diagnosis, and clinical management of COVID-19 have contributed to the control and prevention of this disease, but re-positivity of SARS-CoV-2 in recovered COVID-19 patients has brought a new challenge for this worldwide anti-viral battle. Reverse transcription polymerase chain reaction (RT-PCR) tests of the SARS-CoV-2 pathogen is widely used in clinical diagnosis, but a positive RT-PCR result may be multifactorial, including false positive, SARS-CoV-2 RNA fragment shedding, reinfection of SARS-CoV-2, or re-activation of COVID-19. Re-infection of SARS-CoV-2 or re-activation of COVID-19 is an indicator of live viral carriers and isolation/treatment is needed, but SARS-CoV-2 RNA fragment shedding is not. SARS-CoV-2 RNA is recently reported to integrate into the host genome, but the far-reaching outcome is currently unclear. Therefore, it is critical for appropriate manipulation and prevention of COVID-19 to distinguish these causal factors of SARS-CoV-2 re-positivity. In this review article, we updated the current knowledge of SARS-CoV-2 re-positivity in discharged COVID-19 patients with a focus on re-infection and re-activation. We proposed a hypothetical flowchart for handling of the SARS-CoV-2 re-positive cases.


Subject(s)
COVID-19/pathology , RNA, Viral/analysis , Reinfection/virology , SARS-CoV-2/genetics , Virus Activation/genetics , Adaptive Immunity/immunology , Adolescent , Adult , Aged , Aged, 80 and over , Antibodies, Viral/blood , COVID-19/diagnosis , Child , Child, Preschool , False Positive Reactions , Female , Humans , Infant , Male , Middle Aged , Reverse Transcriptase Polymerase Chain Reaction , Young Adult
9.
BMJ Open ; 11(12): e055126, 2021 12 15.
Article in English | MEDLINE | ID: covidwho-1583095

ABSTRACT

OBJECTIVE: The COVID-19 pandemic is still raging worldwide. While there is significant published evidence on the attributes of patients with COVID-19 from lower-income and middle-income countries, there is a dearth of original research published from Bangladesh, a low-income country in Southeast Asia. Based on a case series from a tertiary healthcare centre, this observational study has explored the epidemiology, clinical profile of patients with COVID-19 and short-term outcomes in Dhaka, Bangladesh. DESIGN AND SETTING: A total of 422 COVID-19-confirmed patients (via reverse transcription-PCR test) were enrolled in this study (male=271, female=150, 1 unreported). We have compiled medical records of the patients and descriptively reported their demographic, socioeconomic and clinical features, treatment history, health outcomes, and postdischarge complications. RESULT: Patients were predominantly male (64%), between 35 and 49 years (28%), with at least one comorbidity (52%), and had COVID-19 symptoms for 1 week before hospitalisation (66%). A significantly higher proportion (p<0.05) of male patients had diabetes, hypertension and ischaemic heart disease, while female patients had asthma (p<0.05). The most common symptoms were fever (80%), cough (60%), dyspnoea (41%) and sore throat (21%). The majority of the patients received antibiotics (77%) and anticoagulant therapy (56%) and stayed in the hospital for an average of 12 days. Over 90% of patients were successfully weaned, while 3% died from COVID-19, and 41% reported complications after discharge. CONCLUSION: The diversity of clinical and epidemiological characteristics and health outcomes of patients with COVID-19 across age groups and gender is noteworthy. Our result will inform the clinicians and epidemiologists of Bangladesh of their COVID-19 mitigation effort.


Subject(s)
COVID-19 , Aftercare , Bangladesh/epidemiology , Cross-Sectional Studies , Female , Humans , Male , Pandemics , Patient Discharge , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2 , Tertiary Care Centers
10.
Eur J Med Res ; 26(1): 147, 2021 Dec 17.
Article in English | MEDLINE | ID: covidwho-1582004

ABSTRACT

BACKGROUND: The outbreak of novel coronavirus disease 2019 (COVID-19) has become a public health emergency of international concern. Quantitative testing of SARS-CoV-2 (severe acute respiratory syndrome coronavirus 2) virus is demanded in evaluating the efficacy of antiviral drugs and vaccines and RT-PCR can be widely deployed in the clinical assay of viral loads. Here, we developed a quantitative RT-PCR method for SARS-CoV-2 virus detection in this study. METHODS: RT-PCR kits targeting E (envelope) gene, N (nucleocapsid) gene and RdRP (RNA-dependent RNA polymerase) gene of SARS-CoV-2 from Roche Diagnostics were evaluated and E gene kit was employed for quantitative detection of COVID-19 virus using Cobas Z480. Viral load was calculated according to the standard curve established by series dilution of an E-gene RNA standard provided by Tib-Molbiol (a division of Roche Diagnostics). Assay performance was evaluated. RESULTS: The performance of the assay is acceptable with limit of detection (LOD) below 10E1 copies/µL and lower limit of quantification (LLOQ) as 10E2 copies/µL. CONCLUSION: A quantitative detection of the COVID-19 virus based on RT-PCR was established.


Subject(s)
COVID-19/diagnosis , Coronavirus Envelope Proteins/genetics , Coronavirus Nucleocapsid Proteins/genetics , Coronavirus RNA-Dependent RNA Polymerase/genetics , Reverse Transcriptase Polymerase Chain Reaction/methods , Humans , Limit of Detection , Phosphoproteins/genetics , SARS-CoV-2/genetics , SARS-CoV-2/isolation & purification , Viral Load/methods
11.
PLoS One ; 16(12): e0260487, 2021.
Article in English | MEDLINE | ID: covidwho-1581781

ABSTRACT

At the start of the COVID-19 pandemic, the Centers for Disease Control and Prevention (CDC) designed, manufactured, and distributed the CDC 2019-Novel Coronavirus (2019-nCoV) Real-Time RT-PCR Diagnostic Panel for SARS-CoV-2 detection. The diagnostic panel targeted three viral nucleocapsid gene loci (N1, N2, and N3 primers and probes) to maximize sensitivity and to provide redundancy for virus detection if mutations occurred. After the first distribution of the diagnostic panel, state public health laboratories reported fluorescent signal in the absence of viral template (false-positive reactivity) for the N3 component and to a lesser extent for N1. This report describes the findings of an internal investigation conducted by the CDC to identify the cause(s) of the N1 and N3 false-positive reactivity. For N1, results demonstrate that contamination with a synthetic template, that occurred while the "bulk" manufactured materials were located in a research lab for quality assessment, was the cause of false reactivity in the first lot. Base pairing between the 3' end of the N3 probe and the 3' end of the N3 reverse primer led to amplification of duplex and larger molecules resulting in false reactivity in the N3 assay component. We conclude that flaws in both assay design and handling of the "bulk" material, caused the problems with the first lot of the 2019-nCoV Real-Time RT-PCR Diagnostic Panel. In addition, within this study, we found that the age of the examined diagnostic panel reagents increases the frequency of false positive results for N3. We discuss these findings in the context of improvements to quality control, quality assurance, and assay validation practices that have since been improved at the CDC.


Subject(s)
COVID-19 , DNA Primers , False Positive Reactions , Humans , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2
12.
Front Public Health ; 9: 743300, 2021.
Article in English | MEDLINE | ID: covidwho-1581123

ABSTRACT

In January 2021, the Chilean city of Concepción experienced a second wave of coronavirus 2019 (COVID-19) while in early April 2021, the entire country faced the same situation. This outbreak generated the need to modify and validate a method for detecting severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in saliva, thereby expanding the capacity and versatility of testing for COVID-19. This study was conducted in February 2021 in the Chilean city of Concepción during which time, the town was under total quarantine. The study participants were mostly symptomatic (87.4%), not hospitalized, and attended care centers because of their health status rather than being asked by the researchers. People coming to the health center in Concepción to be tested for COVID-19 (via reverse transcriptase polymerase chain reaction [RT-PCR]) from a specimen of nasopharyngeal swab (NPS) were then invited to participate in this study. A total of 131 participants agreed to sign an informed consent and to provide saliva and NPS specimens to validate a method in terms of sensitivity, specificity, and statistical analysis of the cycle threshold (Ct) values from the RT-PCR. Calculations pertaining to the 127 participants who were ultimately included in the analysis showed sensitivity and specificity at 94.34% (95% CI: 84.34-98.82%) and 98.65% (95% CI: 92.70-99.97%), respectively. The saliva specimen showed a performance comparable to NPS as demonstrated by the diagnostic parameters. This RT-PCR method from the saliva specimen is a highly sensitive and specific alternative compared to the reference methodology, which uses the NPS specimen. This modified and validated method is intended for use in the in vitro diagnosis of SARS-CoV-2, which provides health authorities in Chile and local laboratories with a real testing alternative to RT-PCR from NPS.


Subject(s)
COVID-19 , SARS-CoV-2 , Saliva/virology , COVID-19/diagnosis , COVID-19 Testing , Chile , Humans , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2/isolation & purification , Specimen Handling
14.
Ann Med ; 53(1): 337-344, 2021 12.
Article in English | MEDLINE | ID: covidwho-1575678

ABSTRACT

BACKGROUND: To minimise the risk of COVID-19 transmission, an ambulant screening protocol for COVID-19 in patients before admission to the hospital was implemented, combining the SARS CoV-2 reverse-transcriptase polymerase chain reaction (RT-PCR) on a nasopharyngeal swab, a chest computed tomography (CT) and assessment of clinical symptoms. The aim of this study was to evaluatethe diagnostic yield and the proportionality of this pre-procedural screeningprotocol. METHODS: In this mono-centre, prospective, cross-sectional study, all patients admitted to the hospital between 22nd April 2020 until 14th May 2020 for semi-urgent surgery, haematological or oncological treatment, or electrophysiological investigationunderwent a COVID-19 screening 2 days before their procedure. At a 2-week follow-up, the presence of clinical symptoms was evaluated by telephone as a post-hoc evaluation of the screening approach.Combined positive RT-PCR assay and/or positive chest CT was used as gold standard. Post-procedural outcomes of all patients diagnosed positive for COVID-19 were assessed. RESULTS: In total,528 patients were included of which 20 (3.8%) were diagnosed as COVID-19 positive and 508 (96.2%) as COVID-19 negative. 11 (55.0%) of COVID-19 positive patients had only a positive RT-PCR assay, 3 (15.0%) had only a positive chest CT and 6 (30%) had both a positive RT-PCR assay and chest CT. 10 out of 20 (50.0%) COVID-19 positive patients reported no single clinical symptom at the screening. At 2 week follow-up, 50% of these patients were still asymptomatic. 37.5% of all COVID-19 negative patients were symptomatic at screening. In the COVID-19 negative group without symptoms at screening, 78 (29.3%) patients developed clinical symptoms at a 2-week follow-up. CONCLUSION: This study suggests that routine chest CT and assessment of self-reported symptoms have limited value in the preprocedural COVID-19 screening due to low sensitivity and/or specificity.


Subject(s)
COVID-19 Testing/methods , COVID-19/diagnosis , Mass Screening/methods , Patient Admission , Adult , Aged , COVID-19/epidemiology , Cross-Sectional Studies , Female , Follow-Up Studies , Humans , Male , Middle Aged , Prospective Studies , Reverse Transcriptase Polymerase Chain Reaction , Sensitivity and Specificity , Tomography, X-Ray Computed
15.
Rev Invest Clin ; 73(6): 339-346, 2021 11 05.
Article in English | MEDLINE | ID: covidwho-1574413

ABSTRACT

BACKGROUND: The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic is a current public health concern. Rapid diagnosis is crucial, and reverse transcription polymerase chain reaction (RT-PCR) is presently the reference standard for SARS-CoV-2 detection. OBJECTIVE: Automated RT-PCR analysis (ARPA) is a software designed to analyze RT-PCR data for SARSCoV-2 detection. ARPA loads the RT-PCR data, classifies each sample by assessing its amplification curve behavior, evaluates the experiment's quality, and generates reports. METHODS: ARPA was implemented in the R language and deployed as a Shiny application. We evaluated the performance of ARPA in 140 samples. The samples were manually classified and automatically analyzed using ARPA. RESULTS: ARPA had a true-positive rate = 1, true-negative rate = 0.98, positive-predictive value = 0.95, and negative-predictive value = 1, with 36 samples correctly classified as positive, 100 samples correctly classified as negative, and two samples classified as positive even when labeled as negative by manual inspection. Two samples were labeled as invalid by ARPA and were not considered in the performance metrics calculation. CONCLUSIONS: ARPA is a sensitive and specific software that facilitates the analysis of RT-PCR data, and its implementation can reduce the time required in the diagnostic pipeline.


Subject(s)
COVID-19/diagnosis , Diagnosis, Computer-Assisted , SARS-CoV-2/isolation & purification , Software , COVID-19 Testing , Humans , Reverse Transcriptase Polymerase Chain Reaction , Saliva/virology
16.
Lab Med ; 52(6): e147-e153, 2021 Nov 02.
Article in English | MEDLINE | ID: covidwho-1574316

ABSTRACT

OBJECTIVE: In this study, the performance of 2 commercially available SARS-CoV-2 antibody assays is evaluated. METHODS: The Siemens SARS-CoV-2 Total (COV2T) and IgG (COV2G) antibody tests were evaluated on a Siemens Atellica IM1300 analyzer. Imprecision was assessed with the CLSI EP15 protocol using positive controls. Ninety control group specimens were analyzed for specificity, and 175 specimens from 58 patients with polymerase chain reaction-confirmed SARS-CoV-2 were measured for the sensitivity and kinetics of the antibody response. RESULTS: Within-run and total imprecision were acceptable for both assays. Both tests showed a specificity of 100%. Sensitivity earlier in the disease state was greater for the COV2T assay than for the COV2G assay, but sensitivity >14 days after onset of symptoms approached 100% for both. For all patients, antibody titers remained above the seroconversion cutoff for all follow-up specimens. CONCLUSION: This study shows acceptable performance for both the Siemens COV2T and COV2G test, although seroconversion occurs earlier with the COV2T test.


Subject(s)
Antibodies, Viral/blood , COVID-19 Serological Testing/standards , COVID-19/diagnosis , Immunoglobulin G/blood , SARS-CoV-2/immunology , Aged , Aged, 80 and over , Automation, Laboratory , COVID-19/blood , COVID-19/immunology , COVID-19/virology , COVID-19 Serological Testing/methods , Enzyme-Linked Immunosorbent Assay/methods , Female , Humans , Male , Reagent Kits, Diagnostic , Retrospective Studies , Reverse Transcriptase Polymerase Chain Reaction/methods , Sensitivity and Specificity
17.
ACS Appl Mater Interfaces ; 13(50): 60612-60624, 2021 Dec 22.
Article in English | MEDLINE | ID: covidwho-1569206

ABSTRACT

New analytical techniques that overcome major drawbacks of current routinely used viral infection diagnosis methods, i.e., the long analysis time and laboriousness of real-time reverse-transcription polymerase chain reaction (qRT-PCR) and the insufficient sensitivity of "antigen tests", are urgently needed in the context of SARS-CoV-2 and other highly contagious viruses. Here, we report on an antifouling terpolymer-brush biointerface that enables the rapid and sensitive detection of SARS-CoV-2 in untreated clinical samples. The developed biointerface carries a tailored composition of zwitterionic and non-ionic moieties and allows for the significant improvement of antifouling capabilities when postmodified with biorecognition elements and exposed to complex media. When deployed on a surface of piezoelectric sensor and postmodified with human-cell-expressed antibodies specific to the nucleocapsid (N) protein of SARS-CoV-2, it made possible the quantitative analysis of untreated samples by a direct detection assay format without the need of additional amplification steps. Natively occurring N-protein-vRNA complexes, usually disrupted during the sample pre-treatment steps, were detected in the untreated clinical samples. This biosensor design improved the bioassay sensitivity to a clinically relevant limit of detection of 1.3 × 104 PFU/mL within a detection time of only 20 min. The high specificity toward N-protein-vRNA complexes was validated both by mass spectrometry and qRT-PCR. The performance characteristics were confirmed by qRT-PCR through a comparative study using a set of clinical nasopharyngeal swab samples. We further demonstrate the extraordinary fouling resistance of this biointerface through exposure to other commonly used crude biological samples (including blood plasma, oropharyngeal, stool, and nasopharyngeal swabs), measured via both the surface plasmon resonance and piezoelectric measurements, which highlights the potential to serve as a generic platform for a wide range of biosensing applications.


Subject(s)
COVID-19 Testing , COVID-19/diagnosis , Coronavirus Nucleocapsid Proteins/chemistry , Nasal Mucosa/virology , Polymers/chemistry , RNA, Viral/metabolism , SARS-CoV-2 , Biofouling , Biological Assay , Biosensing Techniques , Humans , Ions , Limit of Detection , Mass Spectrometry , Nasopharynx/virology , Phosphoproteins/chemistry , Reproducibility of Results , Reverse Transcriptase Polymerase Chain Reaction , Sensitivity and Specificity , Specimen Handling
18.
Lab Med ; 52(6): e154-e158, 2021 Nov 02.
Article in English | MEDLINE | ID: covidwho-1559980

ABSTRACT

OBJECTIVE: This study aims to evaluate the performance of an antigen-based rapid diagnostic test (RDT) for the detection of the SARS-CoV-2 virus. METHODS: A cross-sectional study was conducted on 677 patients. Two nasopharyngeal swabs and 1 oropharyngeal swab were collected from patients. The RDT was performed onsite by a commercially available immune-chromatographic assay on the nasopharyngeal swab. The nasopharyngeal and oropharyngeal swabs were examined for SARS-CoV-2 RNA by real-time reverse-transcription quantitative polymerase chain reaction (RT-qPCR) assay. RESULTS: The overall sensitivity of the SARS-CoV-2 RDT was 34.5% and the specificity was 99.8%. The positive predictive value and negative predictive value of the test were 96.6% and 91.5%, respectively. The detection rate of RDT in RT-qPCR positive results was high (45%) for cycle threshold values <25. CONCLUSION: The utility of RDT is in diagnosing symptomatic patients and may not be particularly suited as a screening tool for patients with low viral load. The low sensitivity of RDT does not qualify its use as a single test in patients who test negative; RT-qPCR continues to be the gold standard test.


Subject(s)
Antigens, Viral/genetics , COVID-19 Serological Testing/standards , COVID-19/diagnosis , Chromatography, Affinity/methods , RNA, Viral/genetics , SARS-CoV-2/genetics , Adolescent , Aged , Aged, 80 and over , Automation, Laboratory , COVID-19/immunology , COVID-19/virology , COVID-19 Serological Testing/methods , Cross-Sectional Studies , Female , Humans , Male , Middle Aged , Nasopharynx/virology , Oropharynx/virology , Reagent Kits, Diagnostic , Reverse Transcriptase Polymerase Chain Reaction/methods , SARS-CoV-2/immunology , Sensitivity and Specificity , Viral Load/genetics
19.
J Virol Methods ; 300: 114411, 2022 Feb.
Article in English | MEDLINE | ID: covidwho-1560621

ABSTRACT

Presence of SARS-CoV-2 RNA in serum (viremia) of COVID-19 patients has been related to poor prognosis and death. The aim of this study was to evaluate both the ability to detect viremia in COVID-19 patients of two commercial reverse real-time-PCR (rRT-PCR) tests, Cobas® and TaqPath™, comparing them with a gold standard method, and their implementation in microbiology laboratories. This retrospective cohort study included 303 adult patients (203 diagnosed with COVID-19 and 100 non-COVID-19 patients) admitted to a tertiary hospital, with at least one serum sample collected within the first 48 h from admission. A total of 365 serum samples were included: 100 from non-COVID patients (pre-pandemic and pandemic control groups) and 265 from COVID-19 patients. Serum samples were considered positive when at least one target was detected. All patients in control groups showed negative viremia. Cobas® and TaqPath™ tests showed specificity and Positive Predictive Value over 96%. Nevertheless, sensitivity (53.72 and 73.63, respectively) and Negative Predictive Value (64.78 and 75) were lower. Viremia difference between ICU and non-ICU patients was significant (p ≤ 0.001) for both techniques. Consequently, SARS-CoV-2 viremia detection by both rRT-PCR tests should be considered a good tool to stratify COVID-19 patients and could be implemented in microbiology laboratories.


Subject(s)
COVID-19 , SARS-CoV-2 , Adult , Humans , RNA, Viral/genetics , Retrospective Studies , Reverse Transcriptase Polymerase Chain Reaction , Sensitivity and Specificity
20.
J Virol Methods ; 300: 114420, 2022 Feb.
Article in English | MEDLINE | ID: covidwho-1560015

ABSTRACT

The emergence and spread of SARS-CoV-2 has led to a compelling request for accurate diagnostic tests. The aim of this study was assessing the performance of a real-time RT-qPCR (rt RT-qPCR) assay and of a droplet digital RT-PCR (dd RT-PCR) targeting the nsp14 genome region for the detection of SARS-CoV-2 in nasopharyngeal swabs. A total of 258 nasopharyngeal swabs were analyzed with the nsp14 assays and, for comparison, with a reference assay targeting the RdRp and E genes. Conflicting results were further investigated by two additional protocols, the Centers for Disease Control and Prevention (CDC) real-time targeting N1/N2, and a nested RT-PCR for the spike region. Agreement of results was achieved on 226 samples (156 positive and 70 negative), 8 samples were positive in the reference assay and in the nsp14 rt RT-qPCR but negative with the dd RT-PCR, and 24 samples provided different combinations of results with the three assays. Sensitivity, specificity and accuracy (95 %C.I.) of the nsp14 assays were: 100.0 % (97.4-100.0), 98.7 % (92.1-100.0), and 99.6 % (97.5-100.0) for the rt RT-qPCR; 92.4 % (87.4-95.6), 100.0 % (94.2-100.0), and 94.7 % (91.1-97.0) for the dd RT-PCR. The results of the study support the use of the nsp14 real-time RT-qPCR and ddPCR for the detection of SARS-CoV-2 in nasopharyngeal swabs.


Subject(s)
COVID-19 , Real-Time Polymerase Chain Reaction , Reverse Transcriptase Polymerase Chain Reaction , SARS-CoV-2 , COVID-19/diagnosis , Exonucleases , Humans , Nasopharynx/virology , RNA, Viral/genetics , SARS-CoV-2/isolation & purification , Sensitivity and Specificity
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