Genetic diversity of respiratory syncytial virus in children with community-acquired pneumonia in Guangzhou: an epidemiological update.

BACKGROUND

Community-acquired pneumonia (CAP) is a common infectious disease with a mortality rate of 2-14%. Respiratory syncytial virus (RSV) frequently causes CAP in children. This study aimed to investigate RSV genetic diversity in children under 15 years of age with CAP, evaluate nucleotide substitution rates, and examine associations with clinical characteristics and outcomes.

METHODS

A retrospective observational study was conducted using nasal swab samples collected from children under 15 years of age diagnosed with CAP. RSV identification involved cell culture and immunofluorescence microscopy, followed by molecular analyses using qPCR, nested PCR, and Sanger sequencing. Bioinformatics tools were applied to assess phylogenetics, evolutionary trends, genetic distance, and nucleotide substitution rates. Statistical analysis of clinical and laboratory data was performed to identify correlations between RSV features and patient characteristics.

RESULTS

Among 346 CAP cases, RSV was detected in 26.88%, with the highest prevalence in children aged 1-2 years. Subtype A exhibited higher nucleotide substitution rates than subtype B. Shortness of breath and high fever were significantly associated with increased nucleotide diversity. RSV infections peaked in winter, particularly in 2018 and 2019. Elevated substitution rates were linked to longer hospital stays, greater risk of complications such as secondary bacterial infections, and increased RSV-related morbidity.

CONCLUSION

RSV higher nucleotide substitution rates, especially in children under 3 years of age, were associated with more severe clinical outcomes and prolonged hospitalization. Phylogenetic analysis indicated distinct evolutionary patterns, with subtype B exhibiting a more rapid evolutionary rate than subtype A.

IMPACT

This study highlights the high prevalence of respiratory viruses, particularly respiratory syncytial virus (RSV), in children with community-acquired pneumonia in Guangzhou. It provides detailed molecular epidemiological data on RSV, including genetic variation patterns and evolutionary rates. The findings contribute regional data essential for epidemiological research and public health planning in similar geographic areas. These results support clinical decision-making and inform public health strategies, particularly those focused on RSV vaccination and infection control.