Clinical evaluation of the Roche distributed SD Biosensor SARS-CoV-2 & Flu A/B Rapid Antigen Test amongst mild symptomatic people during the 2022/2023 winter season.

Both influenza and SARS-CoV-2 are seasonal respiratory illnesses with similar symptoms, however distinguishing one from the other can have benefits for the patient and have different implications in various settings. In this study we have evaluated the clinical performance of the Roche distributed SD Biosensor SARS-CoV-2 & Flu A/B Rapid Antigen Test during the 2022/2023 winter season, in a non-hospitalized, mild symptomatic population, comparing results with reverse transcription quantitative polymerase chain reaction (RT-qPCR). Participants also filled in a short questionnaire about their symptom onset, symptoms, vaccination status for both influenza and SARS-CoV-2. We could include 290 people with complete records with female majority (72%, 209/290). Age ranged from 18 years old (minimum age for inclusion) to 71 years (mean age was 40.4 years). From the 290 inclusions 93 tested positive with SARS-CoV-2 PCR, 12 by influenza A and 6 by influenza B PCR. For SARS-CoV-2 overall sensitivity was 72.0% (confidence interval, CI 61.8-80.9%) and specificity 99.5% (CI 97.2-99.9%). SARS-CoV-2 RDT performed best up to and including PCR ct value of 25 (sensitivity 96% CI 85.8-99.5%), but could also detect samples less or equal to PCR ct 33, however with lower sensitivity (sensitivity 80.0% CI 69.6-88.1%). For influenza limited amount of samples were available; the RDT detected influenza A with 58.3% sensitivity (CI 27.7-84.8) and 100% specificity (CI 98.6-100.0%). In case of influenza B the inclusions were too low to calculate sensitivity reliably (2/6, 33.3% CI 4.3-77.7%); specificity was 98.2% (5/274, CI 95.8-99.4%). No cross reaction between SARS-CoV-2 and Flu A/B was experienced. As was shown before, SARS-CoV-2 could be determined with high sensitivity in recent onset and lower than ct 25 samples. In spite of performing the study throughout the influenza season, we had sub optimal inclusions for determining RDT clinical performance; further studies are needed. ### Competing Interest Statement The authors have declared no competing interest. ### Funding Statement Roche Diagnostics provided the SARS-CoV-2 & Flu Rapid Antigen Tests ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: Ethics committee of Erasmus MC, Rotterdam, The Netherlands waived ethical approval for this work I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes Aggregated data produced in the present study are available upon reasonable request to the authors