The epidemiology of pediatric outpatient acute respiratory tract infections in the US: a multi-facility analysis of multiplex PCR testing from 2018 to 2023
Authors: Timbrook Tristan T. , Glancey Margaret , Noble Brooklyn A. , Eng Stephen , Heins Zoe , Hommel Benjamin , Tessonneau Marie , Galvin Ben W. , Macalino Grace 
Published: December 2023

ABSTRACT
Acute respiratory tract infections in children increase the healthcare burden. Gaps exist in our understanding of the outpatient epidemiology of pediatric respiratory illnesses, especially following the emergence of SARS-CoV-2. The utilization of multiplex PCR testing can enhance our comprehension of these illnesses’ etiology. This study seeks to describe this epidemiology using these diagnostics. This study analyzed respiratory pathogen positivity from multiplex PCR testing between 2018 and 2023. Two multiplex PCR panels were utilized, with 15 viruses and four bacteria on one panel and 11 viruses and three bacteria on the other panel. The endpoints included pathogen rates, coinfection rates, and seasonal variations. Out of 38,778 tests from 16 pediatric sites, 75.3% occurred during 2021–2022. At least one pathogen was detected in 51.9%–67.8% of all tests annually, with human rhinovirus/enterovirus being the most common (27.2%–39.6% annual positivity). Despite a substantial increase in the number of tests per day during the COVID-19 pandemic (5.6 tests performed per day pre-pandemic vs 31.0 tests per day during the pandemic), the pre-pandemic period had similar overall pathogen (66.9% vs 61.4%) and viral (65.2% vs 61.3%) detection rates. This research emphasizes the value of multiplex PCR testing in elucidating the epidemiology of pediatric respiratory diseases between 2018 and 2023. Between 51.9% and 67.8% of annual results detected at least one pathogen, the majority viral. This underscores the significant potential for using data-driven approaches in antimicrobial stewardship to reduce unnecessary antibiotic use. Seasonal fluctuations of non-SARS-CoV-2 viruses suggest a shift toward the epidemiological patterns observed in the pre-pandemic era.

IMPORTANCE
Post-pandemic, it is essential to understand the epidemiology of pediatric acute respiratory tract infections (ARTIs). Our multi-facility study elucidates the outpatient epidemiology of pediatric ARTI using highly multiplexed PCR testing, providing critical insights into the evolving landscape of the etiological agents with a particular focus on the years following the emergence of SARS-CoV-2. Utilizing data from two different multiplex PCR panels, our research provides a comprehensive analysis of respiratory pathogen positivity from 2018 to 2023. Our findings indicate that over half of the annual test results identified at least one pathogen, primarily of viral origin. Intriguingly, despite the surge in testing during the COVID-19 pandemic, pathogen detection rates remain similar to the pre-pandemic era. These data hold significant implications for directing antimicrobial stewardship strategies, curbing unnecessary antibiotic use in pediatric respiratory diseases, and the value of multiplex PCR testing in the outpatient setting among pediatrics.