The changing virology and trends in resource utilization for bronchiolitis since COVID-19.

BACKGROUND: Bronchiolitis is a viral respiratory illness most commonly caused by respiratory syncytial virus (RSV). COVID-19 disrupted typical patterns of viral transmission. Our study aimed to compare low value care for bronchiolitis in a tertiary emergency department (ED) in the United States from March 2017 to March 2022.

METHODS: This was a descriptive cohort study through a retrospective chart review from 2017 to 2022 analyzing ED visits for bronchiolitis including disposition, disease severity, chest radiographs, albuterol, and high flow nasal cannula usage. A year was a 12-month period from March to February.

RESULTS: From 2017 to 2020, there were over 2000 ED visits for bronchiolitis per year (3.1% of all ED visits), which decreased to 450 visits for bronchiolitis (1%) in 2020-2021. Human rhino/enterovirus was the most common virus detected (92%) at that time, and admission rates, albuterol, high flow nasal cannula, and chest radiographs were all higher. The summer of 2021 had the highest visits across the 5-study years with a return to previous rates of resource utilization.

CONCLUSIONS: Bronchiolitis ED visits due to RSV dramatically reduced during the first year of the COVID-19 pandemic in 2020, with over 80% reduction in bronchiolitis visits from 2018 to 2019. While all ED visits fell in 2020, the proportion of visits due to bronchiolitis also decreased. There was an increase in lower value care during the rhinovirus dominant, low census period. As restrictions lifted in 2021, there was a large resurgence of RSV in the atypical summer months with a return of previous rates of resource utilization.