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

• Type of Material: Article
• Authors: Anuradha Rao, Emory University; Adrianna Westbrook, The Atlanta Center for Microsystems-Engineered Point-of-Care Technologies, Atlanta; Leda Bassit, Emory University; Richard Parsons, The Atlanta Center for Microsystems-Engineered Point-of-Care Technologies, Atlanta; Eric Fitts, Emory University; Morgan Greenleaf, The Atlanta Center for Microsystems-Engineered Point-of-Care Technologies, Atlanta; Kaleb McLendon, The Atlanta Center for Microsystems-Engineered Point-of-Care Technologies, Atlanta; Julie A Sullivan, The Atlanta Center for Microsystems-Engineered Point-of-Care Technologies, Atlanta; William Oâ Sick, The Atlanta Center for Microsystems-Engineered Point-of-Care Technologies, Atlanta; Tyler Baugh, The Atlanta Center for Microsystems-Engineered Point-of-Care Technologies, Atlanta; Heather B Bowers, Emory University; Filipp Frank, Emory University; Ethan Wang, Emory University; Mimi Le, Emory University; Jennifer Frediani, Emory University; Pavitra Roychoudhury, University of Washington, Seattle; Alexander L Greninger, University of Washington, Seattle; Robert Jerris, Emory University; Nira R Pollock, Boston Children's Hospital and Harvard Medical School; Eric Ortlund, Emory University; John Roback, Emory University; Wilbur Lam, Emory University
• Language: English
• Date: 2023-02-10
• Publisher: medRxiv
• Publication Version: Preprint (Prior to Peer Review)
• Copyright Statement: The copyright holder for this preprint is the author/funder, who has granted medRxiv a license to display the preprint in perpetuity.
• License: Creative Commons Attribution-NonCommercial-NoDerivs 4.0 International
• Final Published Version (URL): http://dx.doi.org/10.1101/2023.02.09.23285583
• Title of Journal or Parent Work: medRxiv
• Grant/Funding Information: This work was supported by the NIBIB at the NIH under awards 3U54 EB027690-03S1, 3U54 EB027690-03S2, 3U54 EB027690-04S1 and the National Center for Advancing Translational Sciences of the NIH under award UL1TR002378.; This work was supported by the National Institute of Biomedical Imaging and Bioengineering under the Atlanta Center for Microsystems Engineered Point-of-Care Technologies (ACME POCT).
• Keywords: SARS-CoV-2

Abstract

Rapid Antigen Tests (RAT) have become an invaluable tool for combating the COVID-19 pandemic. However, concerns have been raised regarding the ability of existing RATs to effectively detect emerging SARS-CoV-2 variants. We compared the performance of eight commercially available, emergency use authorized RATs against the Delta and Omicron SARS-CoV-2 variants using individual patient and serially diluted pooled clinical samples. The RATs exhibited lower sensitivity for Omicron samples when using PCR Cycle threshold (C T ) value (a proxy for RNA concentration) as the comparator. Interestingly, however, they exhibited similar sensitivity for Omicron and Delta samples when using quantitative antigen concentration as the comparator. We further found that the Omicron samples had lower ratios of antigen to RNA, which offers a potential explanation for the apparent lower sensitivity of RATs for that variant when using C T value as a reference. Our findings underscore the complexity in assessing RAT performance against emerging variants and highlight the need for ongoing evaluation in the face of changing population immunity and virus evolution.