Comparison of Sofia 2 Respiratory Syncytial Virus Fluorescent Immunoassay to Real‐Time Polymerase Chain Reaction Assay in Children Under Two Years Old Hospitalized With Acute Respiratory Illness in Amman, Jordan: A Cross‐Sectional Study

Background and Aims Respiratory syncytial virus (RSV) is a leading cause of acute respiratory infection (ARI) in children, particularly in low‐ and middle‐income countries. Rapid diagnosis is important for management and infection control. We aimed to evaluate diagnostic accuracy of Sofia 2 RSV fluorescent immunoassay (FIA) compared to reverse‐transcription quantitative PCR (RT‐qPCR) in children under 2 years hospitalized with ARI in Amman, Jordan. Methods We conducted a prospective viral surveillance study from January 26, 2020 to March 17, 2020, at Al‐Bashir Hospital. Sofia 2 RSV FIA was performed on nasal swabs and compared to RT‐qPCR. We calculated sensitivity, specificity, and Cohen's κ with 95% confidence intervals and assessed factors associated with RSV detection by FIA using logistic regression. Results Of 458 children enrolled, 356 (77.7%) had RSV detected by RT‐qPCR. Sofia 2 RSV FIA demonstrated 76.1% sensitivity (95% CI: 71.3, 80.5%) and 94.1% specificity (95% CI: 87.6, 97.8%) relative to RT‐qPCR. Lower RT‐qPCR cycle threshold value (inversely related to viral load) was significantly associated with Sofia 2 RSV FIA positivity (aOR = 0.75; 95% CI: 0.70, 0.81; p < 0.001). Conclusion Sofia 2 RSV FIA demonstrates potential as a rapid diagnostic test in resource‐limited settings. Further research on its clinical outcomes and cost‐effectiveness could enhance RSV management in children.