Epidemiology of Pediatric Viral Illnesses Before, During, and After the "Tripledemic" Viral Surge.

OBJECTIVES: While children represented a small percentage of those hospitalized during the COVID-19 pandemic, there was a surge of pediatric viral-related admissions in the immediate postpandemic viral season. Our study compares the epidemiology and health care utilization of children with acute respiratory infections during the 2022-2023 season to prepandemic and subsequent postpandemic seasons to see if trends persisted.

METHODS: We examined administrative data for children who presented to 2 urban pediatric emergency departments (ED) during 3 periods: 2017-2020 (prepandemic), 2022-2023 (immediate postpandemic), and 2023-2024 (subsequent postpandemic). Outcomes included hospitalization rate for viral-related indications, stepdown/intensive care unit (ICU) admission, and use of advanced respiratory support. Multivariable regression controlled for demographics and specific viruses.

RESULTS: During the study period, there were 65,313 all-cause ED encounters. Compared with prepandemic seasons, viral-related admissions doubled in 2022-2023. In addition to an increase in ED visits, the odds of viral-related admission increased by 98% [adjusted odds ratio (aOR): 1.98; 99.8% CI: 1.75-2.24], odds of stepdown/ICU admission increased by 131% (aOR: 1.31; 99.8% CI: 1.67-3.21) and odds of advanced respiratory support increased by 70% (aOR: 1.70; 99.8% CI: 1.21-2.40). In 2023-2024, the stepdown/ICU admission rate remained the same compared with 2022-2023, and the odds of advanced respiratory support increased (aOR: 1.79, 99.8% CI: 1.22-2.63). Infection with respiratory syncytial virus increased adjusted odds of more advanced care.

CONCLUSIONS: Pediatric ED visits and hospitalization rate decreased in 2023-2024 compared with the postpandemic surge, but the admission rate remained high compared with prepandemic seasons, percent admitted to stepdown/ICU persisted, and the use of advanced respiratory support continued to increase.