Screening for SARS-CoV-2 in close contacts of individuals with confirmed infection: performance and operational considerations

Zobrist, Stephanie; Oliveira-Silva, Michelle; Vieira, Alexia Martines; Bansil, Pooja; Gerth‐Guyette, Emily; Leader, Brandon T.; Golden, Allison; Slater, Hannah; Cruz, Catherine Duran de Lucena; Garbin, Eduardo; Sagalovsky, Mariana; Pal, Sampa; Gupta, Vin; Wolansky, Leo; Acqua, Deusilene Souza Vieira Dall; Naveca, Felipe Gomes; Nascimento, Valdinete Alves do; Salcêdo, Juan Miguel Villalobos; Drain, Paul K.; Costa, Alexandre Dias Tavares; Domingo, Gonzalo J.; Pereira, Dhélio Batista

doi:10.1101/2022.01.27.22269904

Cited by 3 publications

(12 citation statements)

References 35 publications

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“…This study investigated the relationship between antigen concentration and diagnostic test performance on different types of samples collected in a study conducted in Porto Velho, Brazil, in 2021. 8 The study shows that antigen concentration is closely related to viral load when…”

Section: Discussionmentioning

confidence: 97%

“…Additionally, at each visit, two paired ANS, one NPS, and one saliva sample, from passive saliva that pools naturally in the mouth, were collected. The details of specimen collection have been previously published (supplementary materials in Zobrist et al, 2022 8 ). The STANDARD Q COVID-19 Ag Nasal Test was run on one ANS during the visit.…”

Section: Methodsmentioning

confidence: 99%

“…Running head: Antigen concentration and performance study Version 3.1; June 3, 2022 In 2021, a prospective diagnostic accuracy study was conducted among close contacts of COVID-19-positive index cases in Porto Velho, Brazil. 8…”

Section: Understanding Antigen Concentration Dynamics In Different Sp...mentioning

confidence: 99%

“…Specimens with cycle threshold (Ct) values <30 underwent genomic sequencing. 8 Genomic sequencing for this study was conducted using Illumina COVIDSeq® Test (Illumina Inc., United States), with some modifications, 12 Nextclade (https://clades.nextstrain.org), 13 and lineages were identified using the pangolin tool on its most up-to-date version. 14 All SARS-CoV-2 genomes generated and analyzed in this study are available at the EpiCoV database in GISAID (https://www.gisaid.org) 15 .…”

Section: Genomic Sequencingmentioning

confidence: 99%

“…In 2021, a prospective diagnostic accuracy study was conducted among close contacts of COVID-19-positive index cases in Porto Velho, Brazil. 8 This study evaluated the performance of four tests for SARS-CoV-2—including three rapid antigen tests (STANDARD Q COVID-19 Ag Nasal and Saliva tests [SD Biosensor, Republic of Korea] and the SARS-CoV-2 Ag Test [LumiraDx™ Limited, United Kingdom]), as well as one dual-plexed RT-PCR method that uses minimally processed saliva 9,10 (SalivaDirect™ protocol [Yale University, United States])— against a regulatory-approved RT-PCR assay run on NPS specimens. Here, we present the results of reference antigen concentration measurements on various specimen types collected from this study, and determine the correlations between antigen concentration and viral load.…”

Section: Introductionmentioning

confidence: 99%

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Antigen concentration, viral load, and test performance for SARS-CoV-2 in multiple specimen types

Golden¹,

Oliveira-Silva²,

Slater³

et al. 2022

Preprint

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The relationship between N-antigen concentration and viral load within a specimen and across different specimens is essential for interpretation of rapid diagnostic tests (RDT) clinical performance in different use cases. A prospective study was conducted in Porto Velho, Brazil, to investigate RDT performance in different specimen types as a function of the correlation between antigen concentration and viral load. The study included 214 close contacts with recent exposures to confirmed cases, aged 12 years and older and with various levels of vaccination. Antigen concentration was measured in nasopharyngeal swab (NPS), anterior nares swab (ANS), and saliva specimens. Reverse transcriptase (RT)-PCR was conducted on the NPS and saliva specimens, and two RDTs were conducted on ANS and one on saliva. Antigen concentration correlated with viral load when measured in the same specimen type but not across specimen types. Antigen levels were higher in symptomatic cases compared to asymptomatic/oligosymptomatic cases and lower in saliva compared to NPS and ANS samples. Discordant results between the RDTs conducted on ANS and the RT-PCR on NPS were resolved by antigen concentration values. The analytical limit-of-detection of RDTs can be used to predict the performance of the tests in populations for which the antigen concentration is known. The antigen dynamics across different sample types observed in SARS-CoV-2 disease progression support use of RDTs in nasal samples. Given lower antigen concentrations in saliva, tests using saliva is expected to require improved analytical sensitivity to achieve clinical sensitivity similar to testing of nasal samples.

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Section: Discussionmentioning

confidence: 97%

Section: Methodsmentioning

confidence: 99%

Section: Understanding Antigen Concentration Dynamics In Different Sp...mentioning

confidence: 99%

Section: Genomic Sequencingmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Antigen concentration, viral load, and test performance for SARS-CoV-2 in multiple specimen types

Golden¹,

Oliveira-Silva²,

Slater³

et al. 2022

Preprint

Self Cite

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Integration of serial self-testing for COVID-19 as part of contact tracing in the Brazilian public health system: A pragmatic trial protocol

Green

Manchola

Gerth‐Guyette

et al. 2023

Preprint

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Background:The coronavirus disease (COVID-19) pandemic has led to an unprecedented public health crisis. Insufficient testing continues to limit the effectiveness of the global response to the COVID-19 pandemic. Molecular testing methods such as reverse transcriptase polymerase chain reaction (RT-PCR) continue to be highly centralized and are a sub-optimal option for population surveillance. Rapid antigen tests (Ag-RDTs) offer multiple benefits including low costs, high flexibility to conduct tests in a wide variety of settings, and faster return of results. Recently, self-test Ag-RDTs (STs) have gained approval in several markets and offer the possibility to expand testing, reaching at-risk populations. While STs have the potential to assist the COVID-19 response, test result integrity, reporting, and appropriate linkage to care continue to hinder the widespread implementation of self-testing programs. Methods:This protocol presents a mixed-methods pragmatic trial (ISRCTN91602092) to better understand the feasibility of self-testing as part of a contact tracing strategy within the Brazilian public health system. Approximately 604 close contacts of 150 index cases testing positive for COVID-19 will be enrolled. Close contacts will be randomized to either serial (daily) self-testing over a 10-day follow-up period or a more traditional approach to contact tracing with a professional Ag-RDT at one time point post-exposure. Usability workshops and focus group discussions will also be conducted. Discussion:This study protocol presents a comprehensive plan to assess the effectiveness, operational feasibility, and stakeholder preferences of a serial self-testing strategy for contact tracing within the Brazilian public health system. Our results will contribute to better understanding of the feasibility of a self-testing strategy within the public sector. Potential risks and limitations are discussed. Our findings will have important implications as governments continue working to mitigate the impact of COVID-19, particularly in the context of where to direct limited resources for testing and healthcare infrastructure.

show abstract

Integration of serial self-testing for COVID-19 as part of contact tracing in the Brazilian public health system: A pragmatic trial protocol

Green,

Manchola,

Gerth-Guyette

et al. 2023

PLoS ONE

Self Cite

View full text Add to dashboard Cite

The coronavirus disease (COVID-19) pandemic has led to an unprecedented public health crisis. Insufficient testing continues to limit the effectiveness of the global response to the COVID-19 pandemic. Molecular testing methods such as reverse transcriptase polymerase chain reaction (RT-PCR) continue to be highly centralized and are a sub-optimal option for population surveillance. Rapid antigen tests (Ag-RDTs) offer multiple benefits including low costs, high flexibility to conduct tests in a wide variety of settings, and faster return of results. Self-test Ag-RDTs (STs) have gained approval in several markets and offer the possibility to expand testing, reaching at-risk populations. While STs have the potential to assist the COVID-19 response, test result integrity, reporting, and appropriate linkage to care continue to hinder the widespread implementation of self-testing programs. This protocol presents a mixed-methods pragmatic trial (ISRCTN91602092) to better understand the feasibility of self-testing as part of a contact tracing strategy within the Brazilian public health system. Approximately 604 close contacts of 150 index cases testing positive for COVID-19 will be enrolled. Index cases will be randomized for their close contacts to participate in either serial (daily) self-testing over a 10-day follow-up period or a more traditional approach to contact tracing with a professional Ag-RDT at one time point post-exposure. Usability workshops and focus group discussions will also be conducted. This study protocol presents a comprehensive plan to assess the effectiveness, operational feasibility, and stakeholder preferences of a serial self-testing strategy for contact tracing within the Brazilian public health system. Our results will contribute to better understanding of the feasibility of a self-testing strategy within the public sector. Potential risks and limitations are discussed. Our findings will have important implications as governments continue working to mitigate the impact of COVID-19, particularly in the context of where to direct limited resources for testing and healthcare infrastructure. Registration: This trial is registered at ISCTRN (ISRCTN91602092).

show abstract

Screening for SARS-CoV-2 in close contacts of individuals with confirmed infection: performance and operational considerations

Cited by 3 publications

References 35 publications

Antigen concentration, viral load, and test performance for SARS-CoV-2 in multiple specimen types

Antigen concentration, viral load, and test performance for SARS-CoV-2 in multiple specimen types

Integration of serial self-testing for COVID-19 as part of contact tracing in the Brazilian public health system: A pragmatic trial protocol

Integration of serial self-testing for COVID-19 as part of contact tracing in the Brazilian public health system: A pragmatic trial protocol

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