Abstract

Seasonal influenza virus predominantly evolves through antigenic drift, marked by the accumulation of mutations at antigenic sites. Because of antigenic drift, influenza vaccines are frequently updated, though their efficacy may still be limited due to strain mismatches. Despite the high levels of viral diversity observed across populations, most human studies reveal limited intrahost diversity, leaving the origin of population-level viral diversity unclear. Previous studies show host characteristics, such as immunity, might affect within-host viral evolution. Here we investigate influenza A viral diversity in children aged between 6 months and 18 years. Influenza virus evolution in children is less well characterized than in adults, yet may be associated with higher levels of viral diversity given the lower level of pre-existing immunity and longer durations of infection in children. We obtained influenza isolates from banked influenza A-positive nasopharyngeal swabs collected at the Children’s Hospital of Philadelphia during the 2017–18 influenza season. Using next-generation sequencing, we evaluated the population of influenza viruses present in each sample. We characterized within-host viral diversity using the number and frequency of intrahost single-nucleotide variants (iSNVs) detected in each sample. We related viral diversity to clinical metadata, including subjects’ age, vaccination status, and comorbid conditions, as well as sample metadata such as virus strain and cycle threshold. Consistent with previous studies, most samples contained low levels of diversity with no clear association between the subjects’ age, vaccine status, or health status. Further, there was no enrichment of iSNVs near known antigenic sites. Taken together, these findings are consistent with previous observations that the majority of intrahost influenza virus infection is characterized by low viral diversity without evidence of diversifying selection.

Details

Title
Within-host influenza viral diversity in the pediatric population as a function of age, vaccine, and health status
Author
Ashley Sobel Leonard 1 ; Mendoza, Lydia 2 ; McFarland, Alexander G 2 ; Marques, Andrew D 2 ; Everett, John K 2 ; Moncla, Louise 3 ; Bushman, Frederic D 2 ; Odom John, Audrey R 1 ; Hensley, Scott E 2 

 Division of Infectious Diseases, Children’s Hospital of Philadelphia , 3401 Civic Center Blvd., Philadelphia, PA 19104, USA 
 Department of Microbiology, Perelman School of Medicine, University of Pennsylvania , 3400 Civic Center Blvd., Philadelphia, PA 19104, USA 
 Department of Pathobiology, School of Veterinary Medicine, University of Pennsylvania , 3800 Spruce St., Philadelphia, PA 19104, USA 
Publication year
2024
Publication date
2024
Publisher
Oxford University Press
e-ISSN
20571577
Source type
Scholarly Journal
Language of publication
English
ProQuest document ID
3168695844
Copyright
© The Author(s) 2024. Published by Oxford University Press. This work is published under https://creativecommons.org/licenses/by-nc/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.