Epidemiology and genetic evolutionary analysis of influenza virus among
children in Hainan Island, China, 2021 -- 2023
Abstract
Background During the COVID-19 pandemic, we continuously
monitored the epidemiology of influenza virus among pediatric patients
from January 2021 to December 2023 in Hainan Island, China.
Methods In this study, we collected 54,974 nasopharyngeal swab
samples for IAV testing and 53,151 samples for IBV testing from
pediatric outpatients. Additionally, we also collected 19,687
nasopharyngeal swab samples from pediatric inpatients for IAV and IBV
testing. Outpatient samples were screened for IVs infection by the
colloidal gold method. Targeted Next-Generation Sequencing (tNGS) was
used to detect Influenza virus infections in inpatients. Influenza virus
types were identified by analyzing the HA/NA partial regions.
Results The findings revealed a decrease in the infection rate
of IBV over the specified period, while the infection rate of IAV
exhibited a rising trend. Additionally, B/Victoria lineage was the
dominant epidemic strain in 2021, while the epidemic strains in 2022 and
2023 underwent a dynamic transformation from A/H3N2 to A/H1N1.
Phylogenetic analysis revealed close relationships among the circulating
strains. Conclusion Our findings suggest that the predominant
types of influenza viruses in the pediatric population are dynamically
changing, and non-pharmaceutical intervention measures can significantly
impact the infection rate of influenza.