Comparison of antigen- and RT-PCR-based testing strategies for detection of SARS-CoV-2 in two high-exposure settings

Love, Jay; Wimmer, Megan T.; Toth, Damon; Chandran, Arthi; Makhija, Dilip; Cooper, Charles K.; Samore, Matthew H.; Keegan, Lindsay T

doi:10.1371/journal.pone.0253407

Cited by 18 publications

(16 citation statements)

References 22 publications

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“…One of the advantages of using saliva is that repeated surveillance testing of non-symptomatic individuals is possible; it can be difficult for patients to tolerate repeated nasopharyngeal swabs. Frequency tolerability is an often-cited advantage of antigen-based testing over RT-PCR for surveillance, along with cost of the test ( 4 , 27 ). Our saliva test is also low-cost ($4-6 per test including labor and reagents) as it does not require specialized collection devices or extraction reagents ( 13 , 17 ).…”

Section: Discussionmentioning

confidence: 99%

“…Because a large population of infected, contagious individuals are asymptomatic or pre-symptomatic, readily accessible testing is essential to identify and isolate these individuals ( 2 ). Testing frequency and turnaround time are critical components to reducing outbreaks regardless of testing method ( 3 , 4 ); however, supply chain shortages early on in the pandemic limited widespread testing ( 5 , 6 ). Testing capacity was also exacerbated in rural areas with less access to testing centers and clinical laboratories ( 7 – 9 ).…”

Section: Introductionmentioning

confidence: 99%

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Implementation of a Rural Community Diagnostic Testing Strategy for SARS-CoV-2 in Upstate South Carolina

Plumb

Ham

Napolitano

et al. 2022

Front. Public Health

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By developing a partnership amongst a public university lab, local city government officials and community healthcare providers, we established a drive-through COVID-19 testing site aiming to improve access to SARS-CoV-2 testing in rural Upstate South Carolina. We collected information on symptoms and known exposures of individuals seeking testing to determine the number of pre- or asymptomatic individuals. We completed 71,102 SARS-CoV-2 tests in the community between December 2020-December 2021 and reported 91.49% of results within 24 h. We successfully identified 5,244 positive tests; 73.36% of these tests originated from individuals who did not report symptoms. Finally, we identified high transmission levels during two major surges and compared test positivity rates of the local and regional communities. Importantly, the local community had significantly lower test positivity rates than the regional community throughout 2021 (p < 0.001). While both communities reached peak case load and test positivity near the same time, the local community returned to moderate transmission as indicated by positivity 4 weeks before the regional community. Our university lab facilitated easy testing with fast turnaround times, which encouraged voluntary testing and helped identify a large number of non-symptomatic cases. Finding the balance of simplicity, accessibility, and community trust was vital to the success of our widespread community testing program for SARS-CoV-2.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Implementation of a Rural Community Diagnostic Testing Strategy for SARS-CoV-2 in Upstate South Carolina

Plumb

Ham

Napolitano

et al. 2022

Front. Public Health

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“…RATs represent an efficient and cost-effective means for SARS-CoV-2 testing in both symptomatic and asymptomatic screening populations. Love et al recently demonstrated that frequency of testing, regardless of whether RT-PCR or rapid antigen testing is employed, in combination with effective quarantine, can provide an effective strategy to suppress the spread of SARS-CoV-2 ( 12 ). In real-world settings, the need for quarantine could be identified sooner following performance of a RAT, compared to a RT-PCR test, with a reflex RT-PCR test used to confirm the RAT result.…”

Section: Discussionmentioning

confidence: 99%

“…In addition, dedicated infrastructure and technical expertise are not required for RATs during point-of-care testing ( 10 ). Further, RATs have a better predictive value for infectiousness compared to RT-PCR ( 11 ), and recent epidemiological modeling shows that RAT-based surveillance testing, in combination with sequestration, can effectively reduce both disease burden and economic cost associated with the management of COVID-19 ( 12 ).…”

Section: Introductionmentioning

confidence: 99%

Large-Scale SARS-CoV-2 Antigen Testing With Real-World Specimens

Parikh

Cooper

Frogel

et al. 2022

Front. Public Health

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Real-world data are needed to establish SARS-CoV-2 rapid antigen testing (RAT) as an effective and reliable approach for SARS-CoV-2 screening. This study included 1,952,931 individuals who provided upper respiratory specimens during SARS-CoV-2 screening at CityMD urgent care locations in the New York metropolitan area from October 2020 to March 2021. Positive and negative results, as determined by the BD Veritor™ System for Rapid Detection of SARS-CoV-2 antigen (Veritor), were obtained for all individuals, with reflex reverse transcriptase-polymerase chain reaction (RT-PCR) testing performed on a case-by-case basis, per standard of care. Using verification bias adjustment, two alternative model assumptions were utilized for RAT results with missing reflex RT-PCR results. The worst antigen diagnostic performance estimates asserted that missing RT-PCR results would show a distribution similar to those RT-PCR results actually obtained, based on symptom category. The best antigen diagnostic performance estimates asserted that individuals without RT-PCR results had a clinical presentation consistent with RAT results, and, therefore, missing RT-PCR results would agree with RAT results. For patients with symptoms or high-risk exposure, 25.3% (n = 86,811/343,253) of RAT results were positive; vs. 3.4% (n = 53,046/1,559,733) positive for asymptomatic individuals without high-risk exposure. Reflex RT-PCR results were obtained from 46.3% (n = 158,836/343,253) and 13.8% (n = 215,708/1,559,733) of symptomatic and asymptomatic individuals, respectively. RT-PCR confirmed 94.4% (4,265/4,518) of positive and 90.6% (139,759/154,318) of negative RAT results in symptomatic individuals; and confirmed 83.4% (6,693/8,024) of positive and 95.3% (197,955/207,684) of negative RAT results in asymptomatic individuals. Applied assumptions for missing reflex RT-PCR results led to worst performance sensitivity estimates of 77.2 and 38.5% in the symptomatic and asymptomatic populations, respectively; assumptions for best performance estimates led to sensitivity values of 85.6 and 84.2%, respectively. Specificity values, regardless of assumptions or symptom category, ranged from 97.9–99.9%. At 10% SARS-CoV-2 prevalence, RAT positive predictive value was 86.9 and 99.0% for worst and best performance estimates across the total population, respectively; negative predictive values were >95% regardless of the applied assumption. Veritor test performance was consistent with that listed in the manufacturer instructions for use for symptomatic individuals. Real-world evidence should be gathered on RATs to support their efficacy as SARS-CoV-2 persists.

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“…Previous studies comparing antigenic and molecular testing regimes to control COVID-19 report that mass antigen testing alone is an acceptable alternative to strategies that include molecular testing 8,9,10 . In agreement, we found that mass antigen testing at a sufficient sensitivity can detect and isolate almost all individuals infected with a concordant variant.…”

Section: Discussionmentioning

confidence: 99%

Impact of antigen test target failure and testing strategies on the transmission of SARS-CoV-2 variants

Vecchio

Daniels

Brancaccio

et al. 2022

Preprint

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Population testing remains central to COVID-19 control and surveillance, with countries increasingly using antigen tests rather than molecular tests. Here we describe a SARS-CoV-2 variant that escapes N antigen tests due to multiple disruptive amino-acid substitutions in the N protein. By fitting a multistrain compartmental model to genomic and epidemiological data, we show that widespread antigen testing in the Italian region of Veneto favored the undetected spread of the antigen-escape variant compared to the rest of Italy. We highlight novel limitations of widespread antigen testing in the absence of molecular testing for diagnostic or confirmatory purposes. Critically, in the presence of a variant that escapes antigen testing, following up a proportion of negative antigen tests with a molecular test is the optimal testing strategy. Together, these findings highlight the importance of retaining molecular testing for surveillance purposes, also in contexts where the use of antigen tests is widespread.

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Comparison of antigen- and RT-PCR-based testing strategies for detection of SARS-CoV-2 in two high-exposure settings

Cited by 18 publications

References 22 publications

Implementation of a Rural Community Diagnostic Testing Strategy for SARS-CoV-2 in Upstate South Carolina

Implementation of a Rural Community Diagnostic Testing Strategy for SARS-CoV-2 in Upstate South Carolina

Large-Scale SARS-CoV-2 Antigen Testing With Real-World Specimens

Impact of antigen test target failure and testing strategies on the transmission of SARS-CoV-2 variants

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