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

BackgroundRSV is one of the major contributing factors of acute lower respiratory tract infection among younger children who are below five years old; over 95% of the burden falls on low- and middle-income countries. Bangladesh faces a substantial pediatric RSV burden yet lacks post-pandemic whole-genome data. Approval of nirsevimab and maternal vaccines (Arexvy, Abrysvo), underscores the need for region-specific genomic surveillance to inform prevention and control strategies. ObjectivesTo conduct the whole-genome sequencing (WGS) study of RSV in Bangladeshi population, characterizing viral genotypic diversity, phylogenetics, F and G protein mutations, glycosylation dynamics, while generating and depositing complete genomes in GISAID. MethodsBetween August 2024 and December 2025, of 1,390 RSV-positive specimens (Ct [≤]35), 59 high-viral-load samples (Ct [≤]25) were selected for whole-genome sequencing using Oxford Nanopore Technology (ARTIC primers), assembled with MIRA v2.0.0, and analyzed via Augur/Nextstrain, Nextclade, and NetNGlyc/NetOGlyc 4.0. ResultsOf 11,874 patients, 1,390 (11.7%) were RSV-positive (RSV-A 94.6%). From selected 59 RSV-positive cases, 49 high-quality genomes were generated (83.1% pass; 94.7% completeness; median depth 1,500x, range 443-4,948): 43 RSV-A (ON1; A.D.3.7 63%, A.D.3 19%, A.D.3.12 9%, A.D.3.1 7%, A.D.1.11 2%) and 6 RSV-B (BA9/B.D.E.1). S276N at antigenic site II (34.9% RSV-A) and S389P in all RSV-B were detected; neither confers resistance to nirsevimab or palivizumab. An F protein N75 N-glycosylation site was fixed in all RSV-A; RSV-B acquired HVR2 N256 glycan in 67%. All 49 genomes were deposited in GISAID. ConclusionThis WGS study of RSV in the Bangladeshi population confirms LMIC nanopore surveillance feasibility, multi-lineage co-circulation, and intact conservation of all vaccine and antibody targets. Progressive glycan remodeling warrants monitoring. These findings establish a genomic baseline to guide nirsevimab and maternal vaccine deployment in Bangladesh, with direct relevance for RSV surveillance programs across South Asia.