scholarly journals Measurement of SARS-CoV-2 antigens in plasma of pediatric patients with acute COVID-19 or MIS-C using an ultrasensitive and quantitative immunoassay

2021 ◽  
Author(s):  
George B Sigal ◽  
Tanya Novak ◽  
Anu Mathew ◽  
Janet Chou ◽  
Yubo Zhang ◽  
...  
Keyword(s):  
Disease Severity ◽  
Pediatric Patients ◽  
Diagnostic Yield ◽  
High Sensitivity ◽  
Blood Collection ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Blood Draw ◽  
Meso Scale Discovery ◽  
Quantitative Immunoassay

Background: Detection of SARS-CoV-2 antigens in blood has high sensitivity in adults with acute COVID-19, but sensitivity in pediatric patients is unclear. Recent data suggest that persistent SARS-CoV-2 spike antigenemia may contribute to multisystem inflammatory syndrome in children (MIS-C). We quantified SARS-CoV-2 nucleocapsid (N) and spike (S) antigens in blood of pediatric patients with either acute COVID-19 or MIS-C using ultrasensitive immunoassays (Meso Scale Discovery). Methods: Plasma was collected from inpatients (<21 years) enrolled across 15 hospitals in 15 US states. Acute COVID-19 patients (n=36) had a range of disease severity and positive nasopharyngeal SARS-CoV-2 RT-PCR within 24 hours of blood collection. Patients with MIS-C (n=53) met CDC criteria and tested positive for SARS-CoV-2 (RT-PCR or serology). Controls were patients pre-COVID-19 (n=67) or within 24h of negative RT-PCR (n=43). Results: Specificities of N and S assays were 95-97% and 100%, respectively. In acute COVID-19 patients, N/S plasma assays had 89%/64% sensitivity, respectively; sensitivity in patients with concurrent nasopharyngeal swab cycle threshold (Ct) ≤ 35 were 93%/63%. Antigen concentrations ranged from 1.28-3,844 pg/mL (N) and 1.65-1,071 pg/mL (S) and correlated with disease severity. In MIS-C, antigens were detected in 3/53 (5.7%) samples (3 N-positive: 1.7, 1.9, 121.1 pg/mL; 1 S-positive: 2.3 pg/mL); the patient with highest N had positive nasopharyngeal RT-PCR (Ct 22.3) concurrent with blood draw. Conclusions: Ultrasensitive blood SARS-CoV-2 antigen measurement has high diagnostic yield in children with acute COVID-19. Antigens were undetectable in most MIS-C patients, suggesting that persistent antigenemia is not a common contributor to MIS-C pathogenesis.

scholarly journals Diagnosis of SARS-Cov-2 Infection by RT-PCR Using Specimens Other Than Naso- and Oropharyngeal Swabs: A Systematic Review and Meta-Analysis

Diagnostics ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 363
Author(s):  
Vânia M. Moreira ◽  
Paulo Mascarenhas ◽  
Vanessa Machado ◽  
João Botelho ◽  
José João Mendes ◽  
...  
Keyword(s):  
Systematic Review ◽  
Clinical Performance ◽  
Point Of Care ◽  
Meta Analysis ◽  
High Sensitivity ◽  
Nasopharyngeal Swab ◽  
Sample Collection ◽  
Rt Pcr ◽  
Oropharyngeal Swab ◽  
Nucleic Acid Assays

The rapid and accurate testing of SARS-CoV-2 infection is still crucial to mitigate, and eventually halt, the spread of this disease. Currently, nasopharyngeal swab (NPS) and oropharyngeal swab (OPS) are the recommended standard sampling techniques, yet, these have some limitations such as the complexity of collection. Hence, several other types of specimens that are easier to obtain are being tested as alternatives to nasal/throat swabs in nucleic acid assays for SARS-CoV-2 detection. This study aims to critically appraise and compare the clinical performance of RT-PCR tests using oral saliva, deep-throat saliva/posterior oropharyngeal saliva (DTS/POS), sputum, urine, feces, and tears/conjunctival swab (CS) against standard specimens (NPS, OPS, or a combination of both). In this systematic review and meta-analysis, five databases (PubMed, Scopus, Web of Science, ClinicalTrial.gov and NIPH Clinical Trial) were searched up to the 30th of December, 2020. Case-control and cohort studies on the detection of SARS-CoV-2 were included. The methodological quality was assessed using the Quality Assessment of Diagnostic Accuracy Studies 2 (QUADAS 2). We identified 1560 entries, 33 of which (1.1%) met all required criteria and were included for the quantitative data analysis. Saliva presented the higher accuracy, 92.1% (95% CI: 70.0–98.3), with an estimated sensitivity of 83.9% (95% CI: 77.4–88.8) and specificity of 96.4% (95% CI: 89.5–98.8). DTS/POS samples had an overall accuracy of 79.7% (95% CI: 43.3–95.3), with an estimated sensitivity of 90.1% (95% CI: 83.3–96.9) and specificity of 63.1% (95% CI: 36.8–89.3). The remaining index specimens could not be adequately assessed given the lack of studies available. Our meta-analysis shows that saliva samples from the oral region provide a high sensitivity and specificity; therefore, these appear to be the best candidates for alternative specimens to NPS/OPS in SARS-CoV-2 detection, with suitable protocols for swab-free sample collection to be determined and validated in the future. The distinction between oral and extra-oral salivary samples will be crucial, since DTS/POS samples may induce a higher rate of false positives. Urine, feces, tears/CS and sputum seem unreliable for diagnosis. Saliva testing may increase testing capacity, ultimately promoting the implementation of truly deployable COVID-19 tests, which could either work at the point-of-care (e.g. hospitals, clinics) or at outbreak control spots (e.g., schools, airports, and nursing homes).

scholarly journals Evaluation of RNA extraction free method for detection of SARS-COV-2 in salivary samples for mass screening for COVID-19

2021 ◽  
Author(s):  
Sally A. Mahmoud ◽  
Esra Ibrahim ◽  
Subhashini Ganesan ◽  
Bhagyashree Thakre ◽  
Juliet G Teddy ◽  
...  
Keyword(s):  
Sensitivity And Specificity ◽  
Gold Standard ◽  
Rna Extraction ◽  
High Sensitivity ◽  
High Specificity ◽  
Cost Effective ◽  
Kappa Coefficient ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Good Percentage

AbstractIn this current COVID - 19 pandemic, there is a dire need for cost effective and less time-consuming alternatives for SARS-COV-2 testing. The RNA extraction free method for detecting SARS-COV-2 in saliva is a promising option, this study found that it has high sensitivity (85.34%), specificity (95.04%) and was comparable to the gold standard nasopharyngeal swab. The method showed good percentage of agreement (kappa coefficient) 0.797 between salivary and NPS samples. However, there are variations in the sensitivity and specificity based on the RT-PCR kit used. The Thermo Fischer-Applied biosystems showed high sensitivity, PPV and NPV but also showed higher percentage of invalid reports. Whereas the BGI kit showed high specificity, better agreement (kappa coefficient) between the results of saliva and NPS samples and higher correlation between the Ct values of saliva and NPS samples. Thus, the RNA extraction free method for salivary sample serves as an effective alternative for SARS-CoV 2-testing.

scholarly journals Assessment of Coronavirus in the Conjunctival Tears in Pediatric Patients with Asymptomatic COVID-19 Infection in Sohag Government, Egypt

2021 ◽  
Vol 15 (1) ◽  
pp. 83-88
Author(s):  
Hany Mahmoud ◽  
Ahmed Radwan ◽  
Amr El Rashidy ◽  
Hesham M. Hefny ◽  
Amal H. Ali ◽  
...  
Keyword(s):  
Polymerase Chain Reaction ◽  
Pediatric Patients ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Interventional Study ◽  
Chain Reaction ◽  
Intimate Contact ◽  
Asymptomatic Patients ◽  
Systemic Manifestations ◽  
Polymerase Chain

Objective: The present study aims to evaluate coronavirus shedding in the tears of asymptomatic pediatric COVID-19 positive patients. Methods: A prospective interventional study that included a total of 145 pediatric asymptomatic COVID-19 patients hospitalized from 17th May 2020 to 16th July 2020 in Sohag Tropical Hospital. On admission, all of them were COVID-19 positive detected through nasopharyngeal swab. They were in intimate contact with positive symptomatic COVID-19 patients before testing and admission. Reverse Transcriptase Polymerase chain reaction (RT-PCR) was done for tears samples at an interval of 5 days after admission and twice before discharge. Results: Of the 145 asymptomatic pediatric COVID-19 positive patients, no one showed ocular or systemic manifestations. They were silent carriers. Ten were positive for tears sample on admission. They became negative for nasopharyngeal and tear samples before discharge. Conclusion: Pediatric positive COVID-19 patients can shed coronavirus through their tears. Even among asymptomatic patients, transmission through tears is possible.

scholarly journals A Diagnostic Model to Predict SARS-CoV-2 Positivity in Emergency Department Using Routine Admission Hematological Parameters

Diagnostics ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 1566
Author(s):  
Rossana Soloperto ◽  
Giovanna Guiotto ◽  
Giuseppe Tozzi ◽  
Maurizio Fumi ◽  
Angelo Tozzi
Keyword(s):  
Emergency Department ◽  
Hematological Parameters ◽  
False Negative ◽  
Diagnostic Errors ◽  
High Sensitivity ◽  
Nasopharyngeal Swab ◽  
Diagnostic Model ◽  
Rt Pcr ◽  
Early Management ◽  
Cumulative Score

Early detection of SARS-CoV-2 in the emergency department (ED) is a crucial necessity, especially in settings of overcrowding: establishing a pre-diagnostic test probability of infection would help to triage patients and reduce diagnostic errors, and it could be useful in resource-limited countries. Here, we established and validated a clinical predictor of infection based on routine admission hematological parameters. The diagnostic model was developed by comparing 85 consecutive patients with symptomatic COVID-19 confirmed by RT-PCR with 85 symptomatic, SARS-CoV-2-negative controls. Abnormal hematological parameters significantly (p < 0.05) associated with SARS-CoV-2 infection were used to derive a “cumulative score” between 0 and 16. The model was validated in an independent cohort of 170 SARS-CoV-2-positive patients. Several routine hematology parameters were significantly (p < 0.05) associated with SARS-CoV-2 infection. A “cumulative score” score ≥7 discriminated COVID-19-postive patients from controls with a sensitivity of 94% and specificity of 100% (p < 0.001). The high sensitivity of the predictive model was confirmed in the prospective validation set, and the cumulative score (i) predicted SARS-CoV-2 positivity even when the first oro-nasopharyngeal swab RT-PCR result was reported as a false negative in both cohorts and (ii) resulted to be independent from disease severity. The cumulative score based on routine blood parameters can be used to predict an early and accurate diagnosis of SARS-CoV-2 infection in symptomatic patients, thereby facilitating triage and optimizing early management and isolation from the COVID-19 free population, particularly useful in overcrowding situations and in resource-poor settings.

scholarly journals Cost-Effective Pooling of DNA from Nasopharyngeal Swab Samples for Large-Scale Detection of Bacteria by Real-Time PCR

2014 ◽  
Vol 53 (3) ◽  
pp. 1002-1004 ◽  
Author(s):  
Sophie Edouard ◽  
Elsa Prudent ◽  
Philippe Gautret ◽  
Ziad A. Memish ◽  
Didier Raoult
Keyword(s):  
Real Time ◽  
Real Time Pcr ◽  
Large Scale ◽  
High Sensitivity ◽  
High Specificity ◽  
Cost Effective ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Scale Detection ◽  
The Cost

We investigated the potential of pooling DNA from nasopharyngeal specimens to reduce the cost of real-time PCR (RT-PCR) for bacterial detection. Lyophilization is required to reconcentrate DNA. This strategy yields a high specificity (86%) and a high sensitivity (96%). We estimate that compared to individual testing, 37% fewer RT-PCR tests are needed.

scholarly journals Implications in the quantitation of SARS-CoV2 copies in concurrent nasopharyngeal swabs, whole mouth fluid and respiratory droplets

2021 ◽  
Author(s):  
Priya Kannian ◽  
Bagavad Gita Jayaraman ◽  
Swarna Alamelu ◽  
Chandra Lavanya ◽  
Nagalingeswaran Kumarasamy ◽  
...  
Keyword(s):  
Disease Severity ◽  
Severe Disease ◽  
Cross Sectional Study ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Cross Sectional ◽  
Virus Shedding ◽  
Mild Disease ◽  
Copy Numbers ◽  
Respiratory Droplets

AbstractImportanceThe nasopharyngeal swab (NPS) is considered the ideal diagnostic specimen for Covid-19, while WMF is recently promoted due to collection simplicity and importance in disease transmission. There is limited knowledge on the relative viral load in these samples – NPS, whole mouth fluid (WMF) and respiratory droplets (RD; another important source in transmission), on how the loads vary with disease severity and on how much virus is shed.ObjectiveTo quantify and compare SARS-CoV2 copies in the NPS, WMF and RD samples, and correlate with disease severity.DesignCross sectional study.SettingTertiary care multi-speciality hospital with limited resources in a low-to-middle income country.ParticipantsEighty suspected COVID-19 patients were recruited from the COVID-19 out-patient clinic and hospital isolation wards.InterventionConcurrent NPS, WMF and RD samples were collected from all the recruited patients and tested for SARS-CoV2 copies by quantitative reverse transcriptase-polymerase chain reaction (RT-PCR).Main outcomes and measuresThe main outcome was COVID-19 measured by SARS-CoV2 quantitative RT-PCR in NPS samples. COVID-19 disease severity was determined according to NIH criteria. Virus shedding was defined as the presence of SARS-CoV2 copies in the WMF and RD samples.ResultsSARS-CoV2 was detected in 55/80 (69%) of the NPS samples. Of these 55, WMF and RD samples were positive in 44 (80%) and 17 (31%), respectively. The concordance of WMF with NPS was 84% (p=0.02). SARS-CoV2 copy numbers were comparable in the NPS (median: 8.74×10^5) and WMF (median: 3.07×10^4), but lower in RD samples (median: 3.60×10^2). Patients with mild disease had higher copies in the NPS (median: 3.46×10^6), while patients with severe disease had higher copies in the WMF (median: 1.34×10^6) and RD samples (median: 4.29×10^4). The 25-75% interquartile range of NPS SARS-CoV2 copies was significantly higher in the WMF (p=0.0001) and RD (p=0.01) positive patients.Conclusion and relevanceSARS-CoV2 copies are highest in NPS samples. WMF is a reliable surrogate sample for diagnosis. High copy numbers in the NPS imply initial virological phase and higher risk of virus shedding via WMF and RD.Key pointsQuestionHow the numbers of SARS-CoV2 copies in nasopharyngeal swab (NPS) samples might reflectvirus shedding from the whole upper aerodigestive tract and indicatedisease severity?FindingsIn this cross-sectional study involving 80 suspected COVID-19 patients, the data indicate higher SARS-CoV2 copies in NPS samples of patients with mild disease,and in the whole mouth fluid (WMF) and respiratory droplet (RD) samples of patients with severe disease. Patients with higher SARS-CoV2 copies in the NPS shed the virus in the WMF and RD samples at statistically higher levels.MeaningHigh SARS-CoV2 copies in NPS samples imply initial virological phase withhigh levels of shedding through both WMF and RD.

scholarly journals SARS-CoV-2 N-antigenemia: A new alternative to nucleic acid amplification techniques

2020 ◽  
Author(s):  
Quentin Le Hingrat ◽  
Benoit Visseaux ◽  
Cedric Laouenan ◽  
Sarah Tubiana ◽  
Lila Bouadma ◽  
...  
Keyword(s):  
Nucleic Acid Amplification ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Serum Samples ◽  
Blood Draw ◽  
Scarce Resources ◽  
Viral Loads ◽  
Molecular Assays ◽  
Plasma Methods ◽  
Antigen Testing

Background. Molecular assays on nasopharyngeal swabs remain the cornerstone of COVID-19 diagnostic. Despite massive worldwide efforts, the high technicalities of nasopharyngeal sampling and molecular assays, as well as scarce resources of reagents, limit our testing capabilities. Several strategies failed, to date, to fully alleviate this testing process (e.g. saliva sampling or antigen testing on nasopharyngeal samples). We assessed the performances of a new ELISA microplate assay quantifying SARS-CoV-2 nucleocapsid antigen (N-antigen) in serum or plasma. Methods. The specificity of the assay, determined on 63 non-COVID patients, was 98.4% (95% confidence interval [CI], 85.3 to 100). Performances were determined on 227 serum samples from 165 patients with RT-PCR confirmed SARS-CoV-2 infection included in the French COVID and CoV-CONTACT cohorts. Findings. Sensitivity was 132/142, 93.0% (95% CI, 84.7 to 100), within the first two weeks after symptoms onset. A subset of 73 COVID-19 patients had a serum collected within 24 hours following or preceding a positive nasopharyngeal swab. Among patients with high nasopharyngeal viral loads, Ct value below 30 and 33, only 1/50 and 4/67 tested negative for N-antigenemia, respectively. Among patients with a negative nasopharyngeal RT-PCR, 8/12 presented positive N-antigenemia. The lower respiratory tract was explored for 6/8 patients, showing positive PCR in 5 cases. Interpretation. This is the first demonstration of the N-antigen antigenemia during COVID-19. Its detection presented a robust sensitivity, especially within the first 14 days after symptoms onset and high nasopharyngeal viral loads. These findings have to be confirmed with higher representation of outpatients. This approach could provide a valuable new option for COVID-19 diagnosis, only requiring a blood draw and easily scalable in all clinical laboratories.

scholarly journals Effects and Safety of Convalescent Plasma Administration in a Group of Polish Pediatric Patients with COVID-19: A Case Series

Life ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 247
Author(s):  
Paweł Małecki ◽  
Kamil Faltin ◽  
Anna Mania ◽  
Katarzyna Mazur-Melewska ◽  
Agnieszka Cwalińska ◽  
...  
Keyword(s):  
Pediatric Patients ◽  
Case Series ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
C Reactive Protein ◽  
Virus Elimination ◽  
Reactive Protein ◽  
Promising Treatment ◽  
Pcr Method ◽  
The Mean

Despite the enormous advances in knowledge about the SARS-CoV-2 infection, the optimal treatment for COVID-19 is still not well defined. The use of convalescent plasma seems to be a promising method of treatment but requires further evaluation. Although it is usually mild, in children with underlying chronic diseases, the course of SARS-CoV-2 infection may be very severe. We described a series of 13 pediatric patients (mean age 10.4 years, median 12) treated with convalescent plasma as a method of COVID-19 therapy. Medical history, with particular emphasis on comorbidities, clinical course, laboratory parameters, supportive treatment and virus elimination time, were analyzed. The mean hospitalization time was 22.6 days (median 20). The most common abnormalities included increased levels of C-reactive protein, D-dimer, and lymphopenia. Median time from symptom onset to convalescent plasma transfusion was 10.6 days (median 7 days). Six patients (46.2%) had a viral clearance on RT-PCR method from a nasopharyngeal swab within 3 days of transfusion, while in the remaining patients the mean elimination time was 12.1 days (median 6 days). Clinical improvement was achieved in all patients; no adverse effects were found in any of the cases. Convalescent plasma may be a promising treatment for COVID-19 in children.

scholarly journals Evaluation of RNA Extraction-Free Method for Detection of SARS-CoV-2 in Salivary Samples for Mass Screening for COVID-19

2021 ◽  
Vol 2021 ◽  
pp. 1-6
Author(s):  
Sally A. Mahmoud ◽  
Subhashini Ganesan ◽  
Esra Ibrahim ◽  
Bhagyashree Thakre ◽  
Juliet G. Teddy ◽  
...  
Keyword(s):  
Predictive Value ◽  
Rna Extraction ◽  
Screening Method ◽  
High Sensitivity ◽  
High Specificity ◽  
Cost Effective ◽  
Kappa Coefficient ◽  
Nasopharyngeal Swab ◽  
Rt Pcr ◽  
Good Agreement

In this COVID-19 pandemic, there is a dire need for cost-effective and less time-consuming alternatives for SARS-CoV-2 testing. The RNA extraction-free method for detecting SARS-CoV-2 in saliva is a promising option. This study found that it has high sensitivity (85.34%), specificity (95.04%), and was comparable to the gold standard nasopharyngeal swab (NPS) sample tests. The method showed good agreement between salivary and NPS samples, with a kappa coefficient of 0.797. However, there are variations in the sensitivity and specificity based on the RT-PCR kit used. The Thermo Fisher Applied Biosystems showed high sensitivity, positive predictive value (PPV), and negative predictive value (NPV) but also showed a higher percentage of invalid reports. On the other hand, the BGI kit showed high specificity, better agreement (kappa coefficient) between the results of saliva and NPS samples, and higher correlation between the Ct values of saliva and NPS samples. Thus, the RNA extraction-free method for salivary sample serves as an effective alternative screening method for COVID-19.

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