Trends in Pediatric Viral Symptoms, Influenza Testing, and SARS-CoV-2 Testing From a Statewide Electronic Health Record Consortium, January 2017 to July 2021

Objective: The heterogeneous implementation and uptake of nonpharmaceutical interventions (NPIs) during the coronavirus disease 2019 (COVID-19) pandemic amplified the need for locally responsive disease surveillance mechanisms. Using data from a newly developed statewide electronic health record (EHR) consortium in Minnesota, we sought to characterize trends in pediatric viral symptoms, influenza testing, and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) testing.

Methods: We conducted a serial cross-sectional analysis of EHR data from 1/1/2017 to 7/30/2021 across 8 large health systems in Minnesota. We included patients ≤18 years of age with any SARS-CoV-2 test, influenza test, or documented diagnostic code which met our viral symptom definition. We plotted week-by-week trends in viral symptoms, SARS-CoV-2 and influenza testing, and test positivity, stratified between children (0-11 years) and adolescents (12-18 years).

Results: We identified 1,079,924 patients ≤18 years of age with viral symptoms or testing; 880,669 (81.5%) were children ≤11 years. Influenza testing and influenza test positivity remained well below historical averages from March 2020 through mid-May 2021. Peaks in viral symptoms during this time were concomitant with peaks in SARS-CoV-2 testing and test positivity, whereas influenza testing and test positivity remained stagnant. Influenza test positivity rates increased substantively among children from May through July 2021.

Conclusions: Viral illness and influenza testing among pediatric patients were below historical averages throughout the COVID-19 pandemic. Ongoing increases in influenza test positivity may merit clinical and public health awareness and intervention. Future NPI policies can be better targeted with insights from collaborative EHR-based surveillance, which enhances real-time, locally sensitive measurement of disease outbreaks.