The prevalence of childhood asthma: interpreting falling rates in the context of shifting measurement and the COVID-19 pandemic.

PURPOSE OF REVIEW: The estimated prevalence of childhood asthma in the United States, as measured by the National Health Information Survey (NHIS), has decreased by 30% since 2017. This review provides context for observed changes in asthma rates by describing recent shifts in NHIS data collection and analysis, and considers whether the COVID-19 pandemic might impact asthma prevalence in years to come.

RECENT FINDINGS: The NHIS underwent a planned redesign in 2019 with updated sampling weights to better match the U.S. population. In early 2020, the COVID-19 pandemic resulted in unplanned modifications to NHIS implementation, which may have included fewer children from populations at a heightened risk for asthma. Decreasing prevalence estimates in recent years are likely at least in part due to these survey changes rather than true epidemiologic shift. However, pandemic-related changes to risk factors for childhood asthma (including exposure to rhinovirus infections and allergic sensitization) may also influence prevalence in the future.

SUMMARY: Recent changes in estimated rates of childhood asthma in the USA are likely driven by changes to survey methods and implementation, both before and during the COVID-19 pandemic. Additional years of data are needed to determine whether a true shift in disease prevalence is occurring.