Evaluation of molecular detection for respiratory syncytial viruses in World Health Organization Europe region laboratories, 2020–2023

Background: Respiratory syncytial virus (RSV) is a common pathogen causing mostly mild-symptoms, but in young infants and elderly individuals it can lead to severe disease and death. After the SARS-CoV-2 pandemic, more focus on and testing of patients with respiratory symptoms occurred, which led to an increase in RSV detections. Also, newly developed vaccines and prophylactic and therapeutic antibodies against RSV have been approved for use, increasing attention on the need for quality RSV diagnostics. Objectives: The goal of this study was a broad analysis of the external quality assessment (EQA) data for RSV using data from Quality Control for Molecular Diagnostics (QCMD). Results: Using the QCMD data, performance of NAATs for detecting RSV was evaluated on an average of 67 laboratories per year, in an average of 21 countries across the WHO Europe region. The results of these EQAs show that the performance of laboratories for RSV molecular diagnostics in the WHO Europe region is good; overall correct scores for core samples between 96.8 % and 99.2 % for RSV-A and between 96.0 % and 100 % for RSV-B for the years 2020–2023. For the years 2020–2023, more tests were performed using commercial assays (63.5–82.0 %) than in-house assays (18.0–36.5 %). Conclusions: Based on analysis of data from the QCMD RSV EQA program during the years 2020–2023, we conclude molecular diagnostics for RSV in laboratories from WHO Europe region are being performed with high-quality. However, with increases in testing, numerous diagnostic assays being used by laboratories, and possible viral changes to newly introduced vaccines and prophylactic/therapeutic antibodies, continued quality assessment of RSV diagnostics is recommended.