Peer-reviewed article
Genomic and Molecular Characterisation of Respiratory Syncytial Virus in the National SARI Surveillance System Across Three Consecutive Seasons in North Macedonia (2022-2025).
Karevska T, Boshevska G, Jancheska E, Vukovikj M, Karishik S et al. ·
Summary
Written by AI, not yet AICS's view · claude-haiku-4-5-20251001This study examined respiratory syncytial virus (RSV) infections detected through hospital surveillance in North Macedonia over three seasons from 2022 to 2025. Researchers tested over 1,800 patients with severe respiratory infections and found RSV in about a quarter of those screened, predominantly affecting young children under 2 years old. The study used genetic sequencing to track how the virus circulated and evolved across seasons, finding that RSV-A strains changed more frequently while RSV-B remained relatively stable. The findings provide baseline genetic information that could help evaluate future RSV vaccines or treatments if they are introduced in the country.
Key points
- RSV was detected in 24.8% of tested SARI cases, with 53.3% of 1,899 cases screened for RSV
- RSV infections concentrated in young children aged 0-2 years
- RSV-A subgroup predominated overall with seasonal shifts in dominance observed
- Whole-genome sequencing of 85 samples showed dynamic seasonal turnover of RSV-A lineages, while RSV-B remained confined to a single dominant lineage
- G protein gene showed greater genetic variability than F protein gene in both RSV subgroups
Limitations
This is a descriptive surveillance study without comparison groups or intervention evaluation, so it cannot establish causation or determine the effectiveness of treatments. The study cannot explain why RSV concentrates in young children or predict future disease burden.
Abstract
Objective To describe the epidemiological, molecular, and genomic characteristics of respiratory syncytial virus (RSV) detected through the national severe acute respiratory infection (SARI) surveillance system in North Macedonia across three consecutive seasons (2022/2023-2024/2025). Materials and methods This study analysed SARI surveillance data from seven hospital-based sentinel sites. RSV detection and subgroup determination were performed using reverse transcription quantitative polymerase chain reaction (RT-qPCR), following season-specific testing strategies, which should be considered when interpreting seasonal differences in RSV positivity. Consensus genomes were generated, and phylogenetic analyses were performed using contemporaneous European reference sequences. Amino acid substitutions in the G and F proteins were assessed descriptively. Results Among 1,899 laboratory-tested SARI cases, 53.3% were tested for RSV, of which 24.8% were positive. RSV-A predominated overall, although seasonal shifts in subgroup dominance were observed. RSV infections were concentrated among young children, particularly those aged 0-2 years. Whole-genome sequencing of 85 RSV-positive samples revealed a dynamic seasonal turnover of RSV-A lineages, whereas RSV-B circulation remained largely confined to a single dominant lineage across seasons. Analysis of antigenically important genes showed greater variability in the G gene compared with the more conserved F gene in both subgroups. Conclusion The integration of epidemiological, molecular, and whole-genome data within routine SARI surveillance provides a comprehensive overview of RSV circulation and evolution in North Macedonia. These findings contribute genomic data from an under-represented region and provide a foundation for future evaluation of RSV vaccination and monoclonal antibody effectiveness by detecting viral genetic changes, should such measures be implemented in North Macedonia.