Genomic Surveillance of Respiratory Syncytial Virus among Patients with Acute Respiratory Infection through Hospital-Based Influenza Surveillance Platforms in Bangladesh, August 2024-December 2025

Background: RSV is a major cause of severe lung infections in young children, with over 95% of deaths occurring in poorer countries. Bangladesh has high rates of RSV illness in children but lacks genetic data from after the COVID-19 pandemic. New vaccines and antibody treatments are now available, making local genetic information essential. Objectives: We sequenced complete RSV genomes from Bangladeshi patients to study virus types, genetic changes, and protein mutations, and shared our data openly. Methods: From August 2024 to December 2025, we took 59 RSV-positive samples with high virus levels from hospital patients and sequenced their full genomes using Oxford Nanopore technology. Results: Among 11,874 patients, 1,390 (11.7%) had RSV, mostly RSV-A (94.6%). We obtained 49 good-quality full genomes from the 59 samples (83% success): 43 RSV-A (ON1 type, five sub-lineages) and 6 RSV-B (BA9 type). We found S276N in 35% of RSV-A and S389P in all RSV-B, but neither stops current antibody treatments. All RSV-A viruses gained a new sugar attachment site on their F protein, and most RSV-B viruses gained one too. We uploaded all 49 genomes to GISAID for public use. Conclusion: This work shows we can do full RSV genome sequencing in Bangladesh. The viruses here still match the targets of new vaccines and antibodies, which is reassuring. Our findings provide a foundation for planning RSV prevention in Bangladesh and South Asia.