Abstract
Testing has been central to global policy throughout the SARS-CoV-2 pandemic. Understanding how test sensitivity changes after exposure is crucial for the interpretation of test outcomes and the design of testing-based interventions. Using data from a human challenge study, we derive temporal test sensitivity profiles for lateral flow tests (LFT), quantitative polymerase chain reaction (qPCR) tests and viable virus, measured by focus-forming assay (FFA). The median time to detectability was 2 days (throat swab) and 3 days (nasal) for qPCR and 4 days for LFT (both swabs), and there was strong positive correlation between first LFT positive and first FFA positive for both throat (p=0.00019) and nasal (p=0.00032) swabs, supporting the use of LFTs as a method of detecting infectiousness. Peak LFT sensitivity was 82.4% (67.0%-91.8%) for throat samples, occurring 6 days post-exposure and 93.3% (85.1%-98.0%) for nasal, 7 days post-exposure. These temporal profiles provide quantification of the mean behaviour of these tests and individual-based variability and could inform a framework for investigating future testing-based interventions.
Competing Interest Statement
The authors have declared no competing interest.
Funding Statement
ELD and TDH would like to gratefully acknowledge funding of the NTD Modelling Consortium (NTDMC) by the Bill & Melinda Gates Foundation (BMGF) (grant no. OPP1184344). ELD & TDH gratefully acknowledge funding from the MRC COVID-19 UKRI/DHSC Rapid Response grant MR/V028618/1 and JUNIPER Consortium (MR/V038613/1). Views, opinions, assumptions or any other information set out in this article should not be attributed to BMGF or any person connected with them. All funders had no role in the study design, collection, analysis, interpretation of data, writing of the report, or decision to submit the manuscript for publication.
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The study used ONLY openly available human data that were originally located at: https://doi.org/10.21203/rs.3.rs-1121993/v1
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Data Availability
All data produced are available online at https://github.com/emmalouisedavis/temporaltestsensitivity