Speaker
Description
Background: Respiratory Syncytial Virus (RSV) is a leading cause of acute respiratory tract infection, with greatest impact on infants, immunocompromised individuals, and older adults. RSV prevalence decreased substantially following the implementation of non-pharmaceutical interventions to mitigate the SARS-CoV-2 pandemic but later rebounded with initially abnormal seasonality. The biological and epidemiological factors underlying this altered behavior remain poorly defined.
Methods: For the present study, we examined RSV epidemiology, clinical severity, and molecular evolution in Chicago, Illinois, US, in the years surrounding the SARS-CoV-2 pandemic. We leveraged a 14-year clinical dataset and a matched biobank of residual diagnostic specimens to assess changes in RSV epidemiology, clinical severity, and viral genetic diversity. We performed multivariable modeling to assess epidemiological and clinical outcome changes. We also performed whole genome viral sequencing, phylogenetic analyses, phylodynamic inference, and selection analyses to understand the viral population changes and selective processes affecting RSV associated to the SARS-CoV-2 pandemic.
Results: Our results indicate that RSV-A was associated with a higher risk of ICU admission among hospitalized adults, consistent with what has been previously reported in pediatric populations. While the population structure of RSV-A remained unchanged, we observed a significant shift in the RSV-B population structure to geographically distinct monophyletic clusters in 2021-2022, likely a result of population bottlenecking during the widespread use of NPIs to mitigate the spread of SARS-CoV-2. Despite the independent emergence of differing RSV-B clusters, the convergent evolution of several mutations in the antigenic regions of F suggests potential alterations to therapeutic efficacy profiles with potential implications for vaccine and therapeutic development.
Conclusions: Overall, efforts to establish and strengthen our understanding of RSV evolution are crucial, as approaching pharmaceutical interventions may further drive diversification and selection in the viral population with global implications.
