Performance of 20 Rapid Antigen Detection Tests to Detect SARS-CoV-2 B.1.617.2 (delta) and B.1.1.529 (omicron) Variants Using a Clinical Specimen Panel from January 2022, Berlin, Germany

Background: There are conflicting reports on the per-formance of rapid antigen detection tests (RDT) in the detection of the SARS-CoV-2 Omicron (B.1.1.529) variant; however, these tests continue to be used frequently to detect potentially contagious individu-als with high viral loads. Aim: The aim of this study was to investigate comparative detection of the Delta (B.1.617.2) and Omicron variants by using a selection of 20 RDT and a limited panel of pooled combined oro-and nasopharyngeal clinical Delta and Omicron speci-mens. Methods: We tested 20 CE-marked RDT for their performance to detect SARS-CoV-2 Delta and Omicron by using a panel of pooled clinical specimens col-lected in January 2022 in Berlin, Germany. Results: We observed equivalent detection performance for Delta and Omicron for most RDT, and sensitivity was widely in line with our previous pre-Delta/Omicron evaluation. Some variation for individual RDT was observed either for Delta vs Omicron detection, or when compared with the previous evaluation, which may be explained both by different panel sizes resulting in different data robustness and potential limitation of batch-to-batch consistency. Additional experiments with three RDT using non-pooled routine clinical samples confirmed comparable performance to detect Delta vs Omicron. Overall, RDT that were previously positively evaluated retained good performance also for Delta and Omicron variants. Conclusion: Our findings suggest that cur-rently available RDT are sufficient for the detection of SARS-CoV-2 Delta and Omicron variants.