Sensitivity of Rapid Antigen Tests Against SARS-CoV-2 Omicron and Delta Variants

Rao, Anuradha; Westbrook, Adrianna; Bassit, Leda; Parsons, Richard; Fitts, Eric C.; Greenleaf, Morgan; McLendon, Kaleb; Sullivan, Julie; O’Sick, William; Baugh, Tyler; Bowers, Heather B.; Frank, Filipp; Wang, Yuanxun Ethan; Le, Mimi; Frediani, Jennifer K.; Roychoudhury, Pavitra; Greninger, Alexander L.; Jerris, Robert C.; Pollock, Nira R.; Ortlund, Eric A.; Roback, John D.; Lam, Wilbur A.; Piantadosi, Anne

doi:10.1101/2023.02.09.23285583

Cited by 8 publications

(10 citation statements)

References 28 publications

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“…The QuickVue RADT showed significantly improved sensitivity against low viral load Omicron samples, consistent with findings by Sugiharto et al (24); however, work by Rao et al (38) showed no change in QuickVue sensitivity against Omicron variants. All other RADTs evaluated in this study showed no significant change in test performance against Omicron variants.…”

Section: Discussionsupporting

confidence: 88%

Post-Market Surveillance of Six COVID-19 Point-of-Care Tests Using Pre-Omicron and Omicron SARS-CoV-2 Variants

Exner,

Gregorchuk,

Castor

et al. 2024

Preprint

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Post-market surveillance of test performance is a critical function of public health agencies and clinical researchers that ensures diagnostics maintain performance characteristics following their regulatory approval. Changes in product quality, manufacturing processes over time, or the evolution of new variants may impact product quality. During the COVID-19 pandemic, a plethora of point-of-care tests (POCTs) were released onto the Canadian market. This study evaluated the performance characteristics of several of the most widely-distributed POCTs in Canada, including four rapid antigen tests (Abbott Panbio, BTNX Rapid Response, SD Biosensor, Quidel QuickVue) and two molecular tests (Abbott ID NOW, Lucira Check IT). All tests were challenged with 149 SARS-CoV-2 clinical positives, including multiple variants up to and including Omicron XBB.1.5, as well as 29 clinical negatives. Results were stratified based on whether the isolate was Omicron or pre-Omicron as well as by RT-qPCR Ct value. The test performance of each POCT was consistent with the manufacturers’ claims and showed no significant decline in clinical performance against any of the variants tested. These findings provide continued confidence in the results of these POCTs as they continue to be used to support decentralized COVID-19 testing. This work demonstrates the essential role of post-market surveillance in ensuring reliability in diagnostic tools.

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Section: Discussionsupporting

confidence: 88%

Post-Market Surveillance of Six COVID-19 Point-of-Care Tests Using Pre-Omicron and Omicron SARS-CoV-2 Variants

Exner,

Gregorchuk,

Castor

et al. 2024

Preprint

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“…Plotting of paired antigen concentrations (measured in the same samples that received PCR testing; Methods) confirmed the same pattern, with median antigen concentrations rising from the day of symptom onset and peaking on the fourth day of symptoms (Fig 1B). To estimate the % of PCR-positive individuals who might be expected to test positive by Ag RDT on each day after symptom onset, the % of participants with a Ct value < 30 (a threshold chosen to represent the most sensitive Ag RDTs commercially available, based on internal data [16]) versus < 25 (representing the least sensitive Ag RDTs available) on each day were calculated (Table 1; see also blue shading, Figure 1A). On the first day of symptoms, sensitivity of rapid testing (compared to PCR) was estimated to range from 35.7-71.4%, and on the fourth day of symptoms, from 78.6-90.6% (Table 1).…”

Section: Resultsmentioning

confidence: 99%

“…Our choice of Ct cutoffs of 25 and 30 for predictions of hypothetical rapid antigen test sensitivity were based both on the numerous studies assessing antigen test sensitivity (versus a variety of PCR assays) at these cutoffs (e.g. [17][18][19][20]) and on internal data evaluating the sensitivity of commercial rapid antigen tests versus the Cepheid Xpert Xpress assay at point-of-care and using omicron swab samples in transport media [16]. In this study, trends observed for directlymeasured antigen concentration distributions very closely mirrored Ct value trends, providing additional support for the antigen test sensitivity predictions and suggesting that the close correlation between Ct value and Ag concentration observed in samples from early in the pandemic remains [21].…”

Section: Discussionmentioning

confidence: 99%

The New Normal: Delayed Peak SARS-CoV-2 Viral Loads Relative to Symptom Onset and Implications for COVID-19 Testing Programs

Frediani

Parsons

McLendon

et al. 2023

Preprint

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Background: Early in the COVID-19 pandemic, peak viral loads coincided with symptom onset. We hypothesized that in a highly immune population, symptom onset might occur earlier in infection, coinciding with lower viral loads. Methods: We assessed SARS-CoV-2 and influenza A viral loads relative to symptom duration in recently-tested adults. Symptomatic participants ≥16y presenting to testing sites in Georgia (4/2022- 4/2023; Omicron variant predominant) provided symptom duration. Nasal swab samples were tested by the Xpert Xpress SARS-CoV-2/Flu/RSV assay and Ct values recorded. Nucleoprotein concentrations in SARS-CoV-2 PCR-positive samples were measured by Single Molecule Array. To estimate hypothetical antigen rapid diagnostic test (Ag RDT) sensitivity on each day after symptom onset, percentages of individuals with Ct value ≤30 or ≤25 were calculated. Results: Of 621 SARS-CoV-2 PCR-positive individuals (64.1% women, median 40.9y), 556/621 (89.5%) had a history of vaccination, natural infection, or both. By both Ct value and antigen concentration measurements, median viral loads rose from the day of symptom onset and peaked on the fourth day. Ag RDT sensitivity estimates were 35.7-71.4% on the first day, 63.9-78.7% on the third day, and 78.6-90.6% on the fourth day of symptoms. In 74 influenza A PCR-positive individuals (55.4% women; median 35.0y), median influenza viral loads peaked on the second day of symptoms. Conclusions: In a highly immune adult population, median SARS-CoV-2 viral loads peaked on the fourth day of symptoms. Influenza A viral loads peaked soon after symptom onset. These findings have implications for ongoing use of Ag RDTs for COVID-19 and influenza.

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“…44,45 The limited number of tests during the Delta variant dominant period in our study precluded robust comparisons of sensitivity between SARS-CoV-2 variants, and there were overlapping confidence intervals for sensitivity across the variants. One study reported lower BinaxNOW COVID-19 Antigen test sensitivity for infections with the Omicron variant compared to those with the Delta variant, 46 and another found no significant difference in sensitivity between the two variants. 47 The impact of infection prevalence, such as the lower prevalence in the Delta period, may have affected the results.…”

Section: Discussionmentioning

confidence: 97%

Diagnostic Accuracy of the Abbot BinaxNOW COVID-19 Antigen Card Test, Puerto Rico

Madewell,

Major,

Graff

et al. 2023

Preprint

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BackgroundThe COVID-19 pandemic underscored the need for rapid and accurate diagnostic tools. In August 2020, the Abbot BinaxNOW COVID-19 Antigen Card test became available as a timely and affordable alternative for SARS-CoV-2 molecular testing, but its performance may vary due to factors including timing and symptomatology. This study evaluates BinaxNOW diagnostic performance in diverse epidemiological contexts.MethodsUsing RT-PCR as reference, we assessed performance of the BinaxNOW COVID-19 test for SARS-CoV-2 detection in anterior nasal swabs from participants of two studies in Puerto Rico from December 2020 to May 2023. Test performance was assessed by days post symptom onset, collection strategy, vaccination status, symptomatology, repeated testing, and RT-PCR cycle threshold (Ct) values.ResultsBinaxNOW demonstrated an overall sensitivity of 84.1% and specificity of 98.8%. Sensitivity peaked within 1–6 days after symptom onset (93.2%) and was higher for symptomatic (86.3%) than asymptomatic (67.3%) participants. Sensitivity declined over the course of infection, dropping from 96.3% in the initial test to 48.4% in testing performed 7–14 days later. BinaxNOW showed 99.5% sensitivity in participants with low Ct values (≤25) but lower sensitivity (18.2%) for participants with higher Cts (36–40).ConclusionsBinaxNOW demonstrated high sensitivity and specificity, particularly in early-stage infections and symptomatic participants. In situations where test sensitivity is crucial for clinical decision- making, nucleic acid amplification tests are preferred. These findings highlight the importance of considering clinical and epidemiological context when interpreting test results and emphasize the need for ongoing research to adapt testing strategies to emerging SARS-CoV-2 variants.

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Sensitivity of Rapid Antigen Tests Against SARS-CoV-2 Omicron and Delta Variants

Cited by 8 publications

References 28 publications

Post-Market Surveillance of Six COVID-19 Point-of-Care Tests Using Pre-Omicron and Omicron SARS-CoV-2 Variants

Post-Market Surveillance of Six COVID-19 Point-of-Care Tests Using Pre-Omicron and Omicron SARS-CoV-2 Variants

The New Normal: Delayed Peak SARS-CoV-2 Viral Loads Relative to Symptom Onset and Implications for COVID-19 Testing Programs

Diagnostic Accuracy of the Abbot BinaxNOW COVID-19 Antigen Card Test, Puerto Rico

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