Shifts in Pediatric Respiratory Virus Trends After the COVID-19 Pandemic: Insights From a 12-Year Hospital-Based Study in South Korea.

Abstract

Background: The COVID-19 pandemic disrupted the seasonal patterns of pediatric respiratory infections, likely due to an immunologic gap. However, the roles of weather conditions and viral interactions in age-specific transmission, seasonality, and coinfections remain unclear.

Methods: This retrospective study analyzed data from children hospitalized with respiratory tract infections between January 2012 and December 2023 at a single tertiary center in Korea. Six common respiratory viruses were identified via multiplex polymerase chain reaction (PCR). The study period was divided into prepandemic (January 2012 to January 2020), pandemic (February 2020 to November 2021), and postpandemic (December 2021 to December 2023) periods. Pandemic-period patients (n = 171) were excluded from comparative analyses. Virus positivity, coinfection rates, and demographic differences were assessed using chi-square tests and t-tests. Time-series analysis using seasonal autoregressive integrated moving average models (SARIMA and SARIMAX) was conducted to compare observed and predicted trends.

Results: Among 12,306 hospitalized children, 86.3% were in the prepandemic period and 12.3% in the postpandemic period. Median age rose from 20.0 to 27.0 months. Rhinovirus (21.3%-43.7%) and human metapneumovirus (6.6%-9.6%) increased, while influenza declined (4.8%-2.8%). Seasonal patterns shifted, with higher positivity in summer and autumn. Observed trends diverged from SARIMAX predictions, suggesting changes not fully explained by the meteorological variables included in the model. Coinfections with three or more viruses rose (1.7%-3.0%), and virus-negative proportions decreased (32.6%-16.7%). RSV showed three peaks in the postpandemic period, suggesting possible shifts in viral cocirculation patterns.

Conclusion: Shifts in pediatric respiratory virus patterns were observed in the postpandemic period and were not fully explained by meteorological variables alone, highlighting the need for adaptive surveillance incorporating broader environmental and demographic factors.