Performance of novel digital real-time Novel Digital Real-Time PCR for detection Detection of SARS-CoV-2, respiratory syncytial viruses, and influenza virusesRespiratory Syncytial Viruses, and Influenza Viruses in Ghana

Digital PCR (dPCR) systems offer high sensitivity and reproducibility without requiring external control standards. However, their performance against real-time reverse transcription-PCR (rRT-PCR) for detecting respiratory viruses remains unexplored in Ghana. We therefore evaluated the performance of a novel dPCR, Lab-On-An-Array (LOAA), for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), respiratory syncytial virus (RSV), and influenza viruses type A (Flu A) and B (Flu B). A cross-sectional hospital-based study was conducted between August- 2022- and January- 2023 in Ghana’s Ashanti and Savannah Regions. Oropharyngeal swabs from 356 participants with a median age of 19 years, presenting with suspected respiratory illness, were tested using LOAA and rRT-PCR. Viral RNA was extracted using a Qiagen Viral Mini Kkit (Qiagen Diagnostics GmbH, Germany). LOAA and rRT-PCR tests were performed using Genoplexor^TM COVID-19/Flu/RSV Detection Kit (Optolane Technologies Inc, South Korea) and FluoroType^® SARS-CoV-2/Flu/RSV kits (Hain Lifescience GmbH, Germany), respectively. LOAA’s performance metrics were assessed using rRT-PCR as the gold standard. Overall positivity rates were 29.78% and 30.90% for LOAA and rRT-PCR, respectively. Compared to rRT-PCR, LOAA’s sensitivity was: 87.76% for RSV;, 91.30% for SARS-CoV-2;, 86.21% for Flu B;, and 88.89% for Flu A. Positive predictive value (PPV) was the highest for RSV (97.73%) and lowest for Flu A (61.54%); negative predictive values (NPV) were ≥98.00% for all respiratory viruses. LOAA recorded an “‘almost perfect”’ agreement (κ ≥0.88) with rRT-PCR for RSV, SARS-CoV-2, and Flu B and good agreement for Flu A (κ = 0.72). LOAA is sensitive in detecting SARS-CoV-2, RSV, and Flu B infections,; however, minor improvements for Flu A are required.