Whole-Genome Sequencing and Genetic Diversity of Human Respiratory Syncytial Virus in Patients with Influenza-like Illness in Sicily (Italy) from 2017 to 2023

• Published in: Viruses 2024-05, Vol.16 (6), p.851
• Main Authors: Tramuto, Fabio, Maida, Carmelo Massimo, Randazzo, Giulia, Guzzetta, Valeria, Santino, Arianna, Li Muli, Rita, Costantino, Claudio, Graziano, Giorgio, Amodio, Emanuele, Mazzucco, Walter, Vitale, Francesco
• Format: Article
• Language: English
• Subjects: Adolescent; Adult; Aged; amino acid change; Amino Acid Substitution; Amino acids; Antibodies; Child; Child, Preschool; Epidemiology; Evolution; F protein; Female; Genetic aspects; Genetic diversity; Genetic research; Genetic variability; Genetic Variation; Genome, Viral; Genome-wide association studies; Genomes; Genotype; Glycoproteins; Health aspects; Humans; Immunization; Infant; Infant, Newborn; Infections; Influenza; Influenza, Human - epidemiology; Influenza, Human - virology; mAb; Male; Medical geography; Middle Aged; molecular surveillance; Monoclonal antibodies; Mutation; Pathogens; Peptides; Phylogeny; Proteins; Respiratory syncytial virus; Respiratory Syncytial Virus Infections - epidemiology; Respiratory Syncytial Virus Infections - virology; Respiratory Syncytial Virus, Human - classification; Respiratory Syncytial Virus, Human - genetics; Respiratory Syncytial Virus, Human - immunology; RNA polymerase; Sicily - epidemiology; Surveillance; vaccine; Vaccines; Virus research; Viruses; Whole Genome Sequencing; Young Adult
• ISSN: 1999-4915; 1999-4915
• DOI: 10.3390/v16060851

Monitoring the genetic variability of human respiratory syncytial virus (hRSV) is of paramount importance, especially for the potential implication of key antigenic mutations on the emergence of immune escape variants. Thus, to describe the genetic diversity and evolutionary dynamics of hRSV circulating in Sicily (Italy), a total of 153 hRSV whole-genome sequences collected from 770 hRSV-positive subjects between 2017 and 2023, before the introduction of expanded immunization programs into the population, were investigated. The phylogenetic analyses indicated that the genotypes GA.2.3.5 (ON1) for hRSV-A and GB.5.0.5a (BA9) for hRSV-B co-circulated in our region. Amino acid (AA) substitutions in the surface and internal proteins were evaluated, including the F protein antigenic sites, as the major targets of immunoprophylactic monoclonal antibodies and vaccines. Overall, the proportion of AA changes ranged between 1.5% and 22.6% among hRSV-A, whereas hRSV-B varied in the range 0.8-16.9%; the latter was more polymorphic than hRSV-A within the key antigenic sites. No AA substitutions were found at site III of both subgroups. Although several non-synonymous mutations were found, none of the polymorphisms known to potentially affect the efficacy of current preventive measures were documented. These findings provide new insights into the global hRSV molecular epidemiology and highlight the importance of defining a baseline genomic picture to monitor for future changes that might be induced by the selective pressures of immunological preventive measures, which will soon become widely available.