scholarly journals Comparative analyses of all FDA EUA-approved rapid antigen tests and RT-PCR for COVID-19 quarantine and surveillance-based isolation

2021 ◽  
Author(s):  
Chad R. Wells ◽  
Abhishek Pandey ◽  
Seyed M. Moghadas ◽  
Burton H. Singer ◽  
Gary Krieger ◽  
...  
Keyword(s):  
Relative Effectiveness ◽  
Policy Decision ◽  
Turnaround Time ◽  
Reproductive Number ◽  
Rt Pcr ◽  
Serial Testing ◽  
Test Specificity ◽  
Tool Set ◽  
Antigen Tests ◽  
Pcr Test

AbstractRapid antigen (RA) tests are being increasingly employed to detect COVID-19 infections in quarantine and surveillance. We conducted a comparative analysis of quarantine durations, testing frequencies, and false-positive rates for all of the 18 RA tests with emergency use authorization (EUA) from the FDA, and an RT-PCR test. For each test, we employed a mathematical model of imminent infections to calculate the effective reproductive number in the context of the test used for quarantine or serial testing. We informed the model with data on test specificity, temporal diagnostic sensitivity, and COVID-19 infectiousness. Our results demonstrate that the relative effectiveness of RA and RT-PCR tests in reducing post-quarantine transmission depends on the quarantine duration and the turnaround time of testing results. For quarantines shorter than five days, RA test on entry to and on exit from quarantine reduced onward transmission more than a single RT-PCR test conducted upon exit. Conducting surveillance via serial RT-PCR testing with a 24-h turnaround time, the minimum testing frequency paired with isolation of positives that is required to suppress the effective reproduction number (RE) below one was found to be every six days. RA tests reduce RE below one when conducted at a minimum frequency that ranges from every six days to every eight days. Our analysis also highlights that the risk of onward transmission during serial testing increases with the delay in obtaining the results. These RA test-specific results are an important component of the tool set for policy decision-making, and demonstrate that judicious selection of an appropriate RA test can supply a viable alternative to RT-PCR in efforts to control the spread of disease.

scholarly journals In vivo kinetics of SARS-CoV-2 infection and its relationship with a person’s infectiousness

2021 ◽  
Vol 118 (49) ◽  
pp. e2111477118
Author(s):  
Ruian Ke ◽  
Carolin Zitzmann ◽  
David D. Ho ◽  
Ruy M. Ribeiro ◽  
Alan S. Perelson
Keyword(s):  
Dynamic Models ◽  
False Negative ◽  
Reproductive Number ◽  
Upper Respiratory Tract ◽  
Rt Pcr ◽  
Viral Kinetics ◽  
Antigen Tests ◽  
The Impact ◽  
Kinetics Of

The within-host viral kinetics of SARS-CoV-2 infection and how they relate to a person’s infectiousness are not well understood. This limits our ability to quantify the impact of interventions on viral transmission. Here, we develop viral dynamic models of SARS-CoV-2 infection and fit them to data to estimate key within-host parameters such as the infected cell half-life and the within-host reproductive number. We then develop a model linking viral load (VL) to infectiousness and show a person’s infectiousness increases sublinearly with VL and that the logarithm of the VL in the upper respiratory tract is a better surrogate of infectiousness than the VL itself. Using data on VL and the predicted infectiousness, we further incorporated data on antigen and RT-PCR tests and compared their usefulness in detecting infection and preventing transmission. We found that RT-PCR tests perform better than antigen tests assuming equal testing frequency; however, more frequent antigen testing may perform equally well with RT-PCR tests at a lower cost but with many more false-negative tests. Overall, our models provide a quantitative framework for inferring the impact of therapeutics and vaccines that lower VL on the infectiousness of individuals and for evaluating rapid testing strategies.

scholarly journals Field performance of NowCheck Rapid antigen test for SARS-CoV-2 in Kisumu County, western Kenya

2021 ◽  
Author(s):  
Simon N Onsongo ◽  
Kephas Otieno ◽  
Shannen van Duijn ◽  
Hellen Barsosio ◽  
Emily R Adams ◽  
...  
Keyword(s):  
Low Cost ◽  
Field Performance ◽  
Field Evaluation ◽  
Turnaround Time ◽  
Rt Pcr ◽  
High Demand ◽  
Western Kenya ◽  
Healthcare Facilities ◽  
Antigen Tests ◽  
Study Participants

Abstract Background Low- and middle-income countries (LMICs) are increasingly adopting low-cost Coronavirus disease 2019 (COVID-19) rapid antigen tests to meet the high demand for SARS-CoV-2 testing. Whilst testing using real-time polymerase chain reaction (RT-PCR) is the current gold standard, its widespread use in LMICs is limited by high costs, turnaround times and is not readily available in most places. COVID-19 antigen tests (Ag-RDT) provide a suitable alternative due to their low cost, rapid turnaround time and easy to set up and use. This study aimed to assess the field performance of the NowCheck COVID-19 antigen kit (Ag-RDT) as a point of care test (POCT) in select healthcare facilities in western Kenya. Methods We conducted a prospective multi-facility field evaluation study of the NowCheck COVID-19 rapid antigen test (Ag-RDT) compared to SARS-CoV-2 RT-PCR (RT-PCR). After obtaining informed consent, trained laboratory technicians collected two pairs of oropharyngeal and nasopharyngeal swabs, both antigen and RT-PCR testing, first for Ag-RDT and next for RT-PCR. We performed Ag-RDTs on-site and shared the results with both the study participants and their healthcare providers within 15-30 minutes. We carried out all RT-PCR tests in a central referral laboratory. The turnaround time for RT-PCR results was typically 24-48 hours. We captured the results of both methods using an electronic digital application. Findings Between December 2020 and March 2021, we enrolled 997 participants who met the Kenyan Ministry of Health COVID-19 case definition. The median age of study participants was 39 years (range one to 80 years), with 54% male. Ag-RDT had a sensitivity of 84.5% (76.0-90.8) and a specificity of 94.4% (95% CI: 92.7-95.8) with an accuracy of 94.2% (92.5- 95.6) when a cycle threshold value (Ct value) of ≤35 was used. The highest sensitivity of 87.7% (77.2-94.5) was observed in samples with Ct values ≤ 30 and the highest specificity of 97.5% (96.2-98.5) at Ct value of <40. Interpretation The NowCheck COVID-19 Ag-RDT showed good performance in field evaluation in multiple healthcare facilities in a developing country. The sensitivity of the kit exceeded the minimum recommended cut-off of 80% as recommended by WHO1. The high specificity of this kit at 94.4% at Ct values ≤33 and 97.5% at Ct values <40 matched that of real-time PCR, making it a good rule-out test for symptomatic patients with COVID-19- like symptoms. The faster turnaround time to results, lower cost, simple analytical steps requiring no equipment or infrastructure makes antigen testing an attractive field-screening method to meet the high demand for COVID-19 testing.

scholarly journals Application of a Serial Antigen Based Testing Strategy for SARS-CoV-2 and Student Adherence in a University Setting, Wisconsin — October–November 2020

2021 ◽  
Author(s):  
John Paul Bigouette ◽  
Laura Ford ◽  
Ian Pray ◽  
Kimberly Langolf ◽  
Juliana Kahrs ◽  
...  
Keyword(s):  
Male Students ◽  
Test Results ◽  
Antigen Test ◽  
Testing Strategy ◽  
Rt Pcr ◽  
Testing Strategies ◽  
Serial Testing ◽  
Polymerase Chain ◽  
Antigen Tests ◽  
University Setting

Abstract Background Serial SARS-CoV-2 testing has been implemented at institutions of higher education (IHEs) and other settings. Testing strategies can include algorithms specifying confirmatory reverse transcription polymerase chain reaction (RT-PCR) testing after an antigen test. It is unknown how testing strategies perform detecting SARS-CoV-2, including individual adherence to serial testing requirements. Methods Student serial testing adherence was defined as completing ≥80% of weekly tests from October 5–November 14, 2020 and evaluated using logistic regression. Medical records were reviewed for all positive antigen test encounters and 10% of daily negative antigen test encounters during October 19–November 30, 2020. Results were used to estimate the proportion of individuals requiring only antigen tests, requiring and completing RT-PCR testing, and associated costs of tests. Results Two-thirds (66.5%; 1,166/1,754) of eligible on-campus students adhered to weekly testing; female students were more adherent (adjusted odds ratio [aOR]:2.07, 95% CI:1.66–2.59) than male students. Of all antigen test encounters, 11.5% (1,409/12,305) reported &gt;1 COVID-19 symptoms. Of non-COVID-19 exposed antigen test encounters, 88% (10,386/11,769) did not require confirmatory RT-PCR testing. Only 28% (390/1,387) of testing encounters had an associated recommended confirmatory RT-PCR test performed. We estimated the testing strategy captured 61% (235/389) of predicted RT-PCR positive specimens. Conclusions At this IHE, most students voluntarily adhered to serial testing. The majority of antigen test results did not require confirmatory RT-PCR testing, but when required, most students did not obtain it. Including strategies to increase the proportion of individuals obtaining indicated confirmatory testing might improve the testing program’s performance.

scholarly journals Surveillance testing for SARS-COV-2 infection in an asymptomatic athlete population: a prospective cohort study with 123 362 tests and 23 463 paired RT-PCR/antigen samples

2021 ◽  
Vol 7 (2) ◽  
pp. e001137
Author(s):  
Kimberly Harmon ◽  
Anabelle M de St Maurice ◽  
Adam C Brady ◽  
Sankar Swaminathan ◽  
Doug F Aukerman ◽  
...  
Keyword(s):  
Screening Programme ◽  
Sports Participation ◽  
High Specificity ◽  
Turnaround Time ◽  
Screening Tests ◽  
Rt Pcr ◽  
Pcr Screening ◽  
Testing Approach ◽  
Antigen Tests ◽  
Antigen Testing

ObjectiveTo assess the diagnostic accuracy of antigen compared with reverse transcriptase (RT)-PCR testing in an asymptomatic athlete screening programme and to monitor infection in college athletes.MethodsQuidel Sofia-2 SARS-CoV-2 Antigen Tests were performed daily before sports participation for football, basketball, wrestling and water polo from 29 September 2020 to 28 February 2021. Paired RT-PCR and antigen tests were performed at least once a week. Positive antigen tests were confirmed with RT-PCR.Results81 175 antigen and 42 187 RT-PCR tests were performed, including 23 462 weekly paired antigen/RT-PCR screening tests in 1931 athletes. One hundred and seventy-two athletes had a positive screening RT-PCR (0.4%), of which 83 (48%) occurred on paired testing days. The sensitivity of antigen tests varied with the frequency of RT-PCR testing and prevalence of COVID-19. The sensitivity of antigen testing was 35.7% (95% CI: 17% to 60%) and specificity 99.8% (95% CI: 99.7% to 99.9%) with once-a-week RT-PCR testing after adjusting for school prevalence. Daily antigen testing was similar to RT-PCR testing two to three times a week in identifying infection. Antigen testing identified infection before the next scheduled PCR on 89 occasions and resulted in 234 days where potentially infectious athletes were isolated before they would have been isolated with RT-PCR testing alone. Two athletic-related outbreaks occurred; 86% of total infections were community acquired.ConclusionAntigen testing has high specificity with a short turnaround time but is not as sensitive as RT-PCR. Daily antigen testing or RT-PCR testing two to three times a week is similar. There are benefits and drawbacks to each testing approach.

scholarly journals Duration of Viral Clearance in IDF Soldiers with Mild COVID-19

2020 ◽  
Author(s):  
Tomer Talmy ◽  
Adili Tsur ◽  
Or Shabtay
Keyword(s):  
Healthy Adult ◽  
Young Patients ◽  
Rehabilitation Center ◽  
Rt Pcr ◽  
Mild Disease ◽  
Serial Testing ◽  
Study Population ◽  
Israel Defense Forces ◽  
Isolation Period ◽  
Pcr Test

Policies determining the duration of quarantine and return to work for confirmed COVID-19 patients still lack evidence. We report our findings regarding the duration of viral RNA positivity among a cohort of young patients with mild disease. Between March 20th, 2020, and May 10th, 2020, 219 soldiers were admitted to the Israel Defense Forces Medical Corps (IDF-MC) COVID-19 rehabilitation center following a positive RT-PCR test for SARS-CoV-2. 119 of these patients, 84 (70.6%) males, 35 (29.4%) females with a median age of 21 (IQR 19-25) were classified as having mild disease and had two consecutive negative RT-PCR tests by May 10th, 2020. The median time for SARS-CoV-2 positivity in nasopharyngeal or oropharyngeal swabs in the study population was 21 days (IQR 15-27) from symptom onset, with a range of 4 to 45 days. The results of this study suggest that in young and healthy adult patients with COVID-19, the median duration of viral positivity is around three weeks. This duration is higher than previously reported in other populations. Young and healthy adults comprise much of the population workforce, and the results of this study may assist in determining the isolation period for symptomatic adults and confirmed COVID-19 patients with mild symptoms. Further studies on this topic should look to expand and determine the intervals of serial testing for confirmed patients and determine the duration of SARS-CoV-2 positivity in other populations.

scholarly journals In vivo kinetics of SARS-CoV-2 infection and its relationship with a person's infectiousness

2021 ◽  
Author(s):  
Ruian Ke ◽  
Carolin Zitzmann ◽  
David D Ho ◽  
Ruy Ribeiro ◽  
Alan S Perelson
Keyword(s):  
Dynamic Models ◽  
False Negative ◽  
Reproductive Number ◽  
Upper Respiratory Tract ◽  
Rt Pcr ◽  
Viral Kinetics ◽  
Antigen Tests ◽  
The Impact ◽  
Kinetics Of

The within-host viral kinetics of SARS-CoV-2 infection and how they relate to a person's infectiousness are not well understood. This limits our ability to quantify the impact of interventions on viral transmission. Here, we develop data-driven viral dynamic models of SARS-CoV-2 infection and estimate key within-host parameters such as the infected cell half-life and the within-host reproductive number. We then develop a model linking viral load (VL) to infectiousness, showing that infectiousness increases sub-linearly with VL. We show that the logarithm of the VL in the upper respiratory tract (URT) is a better surrogate of infectiousness than the VL itself. Using data on VL and the predicted infectiousness, we further incorporated data on antigen and reverse transcription polymerase chain reaction (RT-PCR) tests and compared their usefulness in detecting infection and preventing transmission. We found that RT-PCR tests perform better than antigen tests assuming equal testing frequency; however, more frequent antigen testing may perform equally well with RT-PCR tests at a lower cost, but with many more false-negative tests. Overall, our models provide a quantitative framework for inferring the impact of therapeutics and vaccines that lower VL on the infectiousness of individuals and for evaluating rapid testing strategies.

scholarly journals Analytical Evaluation of Visby Medical RT-PCR Portable Device for Rapid Detection of SARS-CoV-2

Diagnostics ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 813
Author(s):  
Adriana Renzoni ◽  
Francisco Perez ◽  
Marie Thérèse Ngo Nsoga ◽  
Sabine Yerly ◽  
Erik Boehm ◽  
...  
Keyword(s):  
Point Of Care ◽  
Turnaround Time ◽  
Nucleic Acid Detection ◽  
Nasopharyngeal Swab ◽  
Analytical Sensitivity ◽  
Rt Pcr ◽  
Detection Systems ◽  
Reverse Transcription Pcr ◽  
Antigen Tests ◽  
Pcr Targeting

Extended community testing constitutes one of the main strategic pillars in controlling the COVID-19 pandemic. Reverse transcription PCR (RT-PCR) targeting the SARS-CoV-2 genome on nasopharyngeal swab samples is currently the reference test. While displaying excellent analytical sensitivity and specificity, this test is costly, often requires a substantial turnaround time, and, more importantly, is subject to reagent and other material shortages. To complement this technology, rapid antigen tests have been developed and made available worldwide, allowing cheap, quick, and decentralized SARS-CoV-2 testing. The main drawback of these tests is the reduced sensitivity when RT-PCR is the gold standard. In this study, we evaluate Visby an innovative, portable, easy-to-use RT-PCR point-of-care (POC) diagnostic device. Our retrospective analysis shows that overall, compared to the Cobas 6800 RT-qPCR assay (Roche), this RT-PCR POC technology detects SARS-CoV-2 RNA with 95% sensitivity (95%CI = 86.3–99%) and 100% specificity (95% CI = 80.5–100%). For samples with cycle-threshold values below 31, we observed 100% sensitivity (95% CI = 66.4–100%). While showing an analytical sensitivity slightly below that of a standard RT-qPCR system, the evaluated Visby RT-PCR POC device may prove to be an interesting diagnostic alternative in the COVID-19 pandemic, potentially combining the practical advantages of rapid antigen tests and the robust analytical performances of nucleic acid detection systems.

scholarly journals Modeling Effectiveness of Testing Strategies to Prevent Coronavirus Disease 2019 (COVID-19) in Nursing Homes—United States, 2020

2021 ◽  
Author(s):  
Isaac See ◽  
Prabasaj Paul ◽  
Rachel B Slayton ◽  
Molly K Steele ◽  
Matthew J Stuckey ◽  
...  
Keyword(s):  
Nursing Homes ◽  
Infection Control ◽  
Relative Sensitivity ◽  
Turnaround Time ◽  
Potential Effect ◽  
Infection Control Practice ◽  
Healthcare Personnel ◽  
Test Frequency ◽  
Testing Strategies ◽  
Serial Testing

Abstract Background Identifying asymptomatic individuals early through serial testing is recommended to control coronavirus disease 2019 (COVID-19) in nursing homes, both in response to an outbreak (“outbreak testing” of residents and healthcare personnel) and in facilities without outbreaks (“nonoutbreak testing” of healthcare personnel). The effectiveness of outbreak testing and isolation with or without nonoutbreak testing was evaluated. Methods Using published SARS-CoV-2 transmission parameters, the fraction of SARS-CoV-2 transmissions prevented through serial testing (weekly, every 3 days, or daily) and isolation of asymptomatic persons compared with symptom-based testing and isolation was evaluated through mathematical modeling using a Reed-Frost model to estimate the percentage of cases prevented (ie, “effectiveness”) through either outbreak testing alone or outbreak plus nonoutbreak testing. The potential effect of simultaneous decreases (by 10%) in the effectiveness of isolating infected individuals when instituting testing strategies was also evaluated. Results Modeling suggests that outbreak testing could prevent 54% (weekly testing with 48-hour test turnaround) to 92% (daily testing with immediate results and 50% relative sensitivity) of SARS-CoV-2 infections. Adding nonoutbreak testing could prevent up to an additional 8% of SARS-CoV-2 infections (depending on test frequency and turnaround time). However, added benefits of nonoutbreak testing were mostly negated if accompanied by decreases in infection control practice. Conclusions When combined with high-quality infection control practices, outbreak testing could be an effective approach to preventing COVID-19 in nursing homes, particularly if optimized through increased test frequency and use of tests with rapid turnaround.

scholarly journals Superiority of MALDI-TOF Mass Spectrometry over Real-Time PCR for SARS-CoV-2 RNA Detection

Viruses ◽  
2021 ◽  
Vol 13 (5) ◽  
pp. 730
Author(s):  
Magda Rybicka ◽  
Ewa Miłosz ◽  
Krzysztof Piotr Bielawski
Keyword(s):  
Mass Spectrometry ◽  
Gold Standard ◽  
Viral Genome ◽  
False Negative ◽  
Rt Pcr ◽  
Rna Detection ◽  
Maldi Tof ◽  
Negative Results ◽  
False Negative Results ◽  
Pcr Test

At present, the RT-PCR test remains the gold standard for early diagnosis of SARS-CoV-2. Nevertheless, there is growing evidence demonstrating that this technique may generate false-negative results. Here, we aimed to compare the new mass spectrometry-based assay MassARRAY® SARS-CoV-2 Panel with the RT-PCR diagnostic test approved for clinical use. The study group consisted of 168 suspected patients with symptoms of a respiratory infection. After simultaneous analysis by RT-PCR and mass spectrometry methods, we obtained discordant results for 17 samples (10.12%). Within fifteen samples officially reported as presumptive positive, 13 were positive according to the MS-based assay. Moreover, four samples reported by the officially approved RT-PCR as negative were positive in at least one MS assay. We have successfully demonstrated superior sensitivity of the MS-based assay in SARS-CoV-2 detection, showing that MALDI-TOF MS seems to be ideal for the detection as well as discrimination of mutations within the viral genome.

scholarly journals COVID-19 Biomarkers and Advanced Sensing Technologies for Point-of-Care (POC) Diagnosis

2021 ◽  
Vol 8 (7) ◽  
pp. 98
Author(s):  
Ernst Emmanuel Etienne ◽  
Bharath Babu Nunna ◽  
Niladri Talukder ◽  
Yudong Wang ◽  
Eon Soo Lee
Keyword(s):  
Response Times ◽  
Rna Virus ◽  
Point Of Care ◽  
Protein Detection ◽  
Turnaround Time ◽  
Quantitative Detection ◽  
Rt Pcr ◽  
Specificity And Sensitivity ◽  
Small Market ◽  
Multiple Biomarkers

COVID-19, also known as SARS-CoV-2 is a novel, respiratory virus currently plaguing humanity. Genetically, at its core, it is a single-strand positive-sense RNA virus. It is a beta-type Coronavirus and is distinct in its structure and binding mechanism compared to other types of coronaviruses. Testing for the virus remains a challenge due to the small market available for at-home detection. Currently, there are three main types of tests for biomarker detection: viral, antigen and antibody. Reverse Transcription-Polymerase Chain Reaction (RT-PCR) remains the gold standard for viral testing. However, the lack of quantitative detection and turnaround time for results are drawbacks. This manuscript focuses on recent advances in COVID-19 detection that have lower limits of detection and faster response times than RT-PCR testing. The advancements in sensing platforms have amplified the detection levels and provided real-time results for SARS-CoV-2 spike protein detection with limits as low as 1 fg/mL in the Graphene Field Effect Transistor (FET) sensor. Additionally, using multiple biomarkers, detection levels can achieve a specificity and sensitivity level comparable to that of PCR testing. Proper biomarker selection coupled with nano sensing detection platforms are key in the widespread use of Point of Care (POC) diagnosis in COVID-19 detection.

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