Genomic Analysis and Evolutionary Trends of Rhinovirus in Western Washington State, 2021–2022

Overview

This study sequenced 1078 rhinovirus genomes from symptomatic and asymptomatic individuals in Western Washington State during two distinct epidemiologic periods of the COVID-19 pandemic. It revealed the cocirculation of diverse rhinovirus genotypes, intergenotypic recombination, and a significant association between viral load and symptom presence, but not with specific species or genotypes.

Background

Human rhinoviruses (RVs) are the primary cause of the common cold and contribute significantly to acute upper respiratory infections. They can also exacerbate chronic respiratory conditions and cause severe disease in immunocompromised patients. Despite their clinical importance, RV genomic data remain limited compared to other respiratory viruses. RVs are classified into three species (RV-A, RV-B, RV-C) with numerous genotypes, complicating vaccine development due to their high antigenic diversity.

Data Highlights

Key Findings

• Detected 99 of 168 known rhinovirus genotypes circulating in Western Washington State.
• Observed intergenotypic recombination and genotype cluster swapping between 2021 and 2022.
• Significant correlation between presence of symptoms and higher viral load, but no correlation with RV species or genotype.
• Phylodynamic analyses revealed cocirculation of divergent clades within genotypes with strong amino acid constraints across the polyprotein.
• More than 20% of existing genotypes within each RV species cocirculated each studied month, indicating high genomic diversity.
• Highlighted the importance of studying genotype-serotype correlations to understand immunity and cross-protection.

Clinical Implications

The high diversity and dynamic evolution of rhinovirus genotypes complicate the development of broadly effective vaccines and therapeutics. Clinicians should be aware that symptom severity correlates more with viral load than with specific rhinovirus species or genotypes. Continued genomic surveillance is essential to monitor evolving strains and inform public health strategies, especially in vulnerable populations.

Conclusion

This comprehensive genomic study underscores the complex and dynamic nature of rhinovirus epidemiology within a localized region, revealing extensive genotype diversity and evolution. These findings emphasize the need for ongoing surveillance and deeper understanding of genotype-serotype relationships to guide future interventions.

References

1. Grubaugh et al. 2023 -- Genomic Analysis and Evolutionary Trends of Rhinovirus in Western Washington State, 2021–2022