In Vitro Rapid Antigen Test Performance with the SARS-CoV-2 Variants of Concern B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma), and B.1.617.2 (Delta).

Sabrina Jungnick,Annika Sprenger,Sonja Hahner,Ute Eberle,Sabrina Hepner,Armin Baiker,Carola Berger,Bernhard Liebl,Andreas Sing,Maren Haase,Volker Fingerle,Bernhard Hobmaier,Mona Hoyos,Siegfried Ippisch,Manfred Wildner,Heidi Lahne,Nikolaus Ackermann,Clara Wimmer,Alexandra Dangel,Lena Mautner

doi:10.3390/microorganisms9091967

Abstract

Rapid antigen tests (RATs) are an integral part of SARS-CoV-2 containment strategies. As emerging variants of concern (VOCs) displace the initially circulating strains, it is crucial that RATs do not fail to detect these new variants. In this study, four RATs for nasal swab testing were investigated using cultured strains of B.1.1 (non-VOC), B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma), and B.1.617.2 (Delta). Based on dilution series in cell culture medium and pooled saliva, the limit of detection of these RATs was determined in a laboratory setting. Further investigations on cross-reactivity were conducted using recombinant N-protein from seasonal human coronaviruses (hCoVs). RATs evaluated showed an overall comparable performance with cultured strains of the non-VOC B.1.1 and the VOCs Alpha, Beta, Gamma, and Delta. No cross-reactivity was detected with recombinant N-protein of the hCoV strains HKU1, OC43, NL63, and 229E. A continuous evaluation of SARS-CoV-2 RAT performance is required, especially with regard to evolving mutations. Moreover, cross-reactivity and interference with pathogens and other substances on the test performance of RATs should be consistently investigated to ensure suitability in the context of SARS-CoV-2 containment.

Highlights

SARS-CoV-2 rapid antigen tests (RATs) are an integral part of SARS-CoV-2 containment strategies
As the majority of currently available SARSCoV-2 Rapid antigen tests (RATs) as well as RATs evaluated in this study are based on detection of the Nprotein [11], these mutations might influence the test performance of N-specific SARSCoV-2 RATs, as well as other automated or laboratory-based tests that rely on detection of the N-protein [12,13]
Our results show that all RATs investigated in this study were able to detect the VOCs B.1.1.7 (Alpha), B.1.351 (Beta), P.1 (Gamma), and B.1.617.2 (Delta) with a comparable performance to the non-VOC

Summary

Introduction

SARS-CoV-2 rapid antigen tests (RATs) are an integral part of SARS-CoV-2 containment strategies. Many RATs have received specific approvals for self-testing and are widely used, for example, in the context of testing strategies in educational institutions or corporate facilities [1,2,3]. Microorganisms 2021, 9, 1967 importance that new SARS-CoV-2 variants of concern (VOCs) do not impair RAT performance. This study was designed as an in vitro approach to investigate if the performance of RATs is affected by VOCs. In addition, a laboratory evaluation was performed to identify potential cross-reactivity with recombinant N-protein of the seasonally circulating human corona viruses (hCoVs) HKU1, OC43, NL63, and 229E. Four common RATs for nasal swab testing were evaluated (Table 1)

Methods

Results

Discussion

Conclusion