Publication date: Aug 14, 2026
Early-life respiratory infections are associated with subsequent asthma development; however, whether respiratory viruses contribute to asthma onset or merely unmask pre-existing susceptibility remains unclear. The COVID-19 pandemic’s non-pharmaceutical interventions (NPIs) suppressed respiratory viruses, followed by their resurgence, offering a natural experiment. We examined whether these population-level changes in respiratory virus activity were associated with changes in newly recorded pediatric asthma diagnoses. We conducted a nationwide interrupted time-series study using Japan’s National Database of Health Insurance Claims, covering approximately 99% of the population. Segmented negative binomial regression with two intervention points-NPI implementation (T1: March 2020) and COVID-19 reclassification (T2: May 2023)-was applied to monthly counts of newly recorded asthma diagnoses among children aged under 19 years (January 2018-March 2024), with atopic dermatitis as negative control. Age-stratified/sex-stratified analyses and exploratory ecological analyses of pathogen-specific associations were conducted. Among 10,508,387 new asthma diagnoses, incidence declined significantly following NPI implementation (incidence rate ratio [IRR] 0. 511, 95% confidence interval [CI] 0. 422-0. 620) and rebounded following NPI relaxation (IRR 1. 395, 95% CI:1. 120-1. 737). Atopic dermatitis showed attenuated changes at both points. Rate differences were greatest in infants (0-1 years) at T1 and school-aged children (5-9 years) at T2. Rhinovirus, respiratory syncytial virus, influenza, and Mycoplasma pneumoniae, but not SARS-CoV-2, correlated with asthma diagnoses in ecological analyses. Newly recorded pediatric asthma diagnoses showed bidirectional changes that paralleled respiratory virus suppression and resurgence, compatible with a possible contributory role of respiratory infections, particularly among infants and school-aged children.
| Concepts | Keywords |
|---|---|
| Asthma | |
| COVID-19 | |
| Interrupted time series | |
| Respiratory syncytial virus | |
| Rhinovirus |
Semantics
| Type | Source | Name |
|---|---|---|
| disease | MESH | asthma |
| pathway | KEGG | Asthma |
| disease | MESH | respiratory infections |
| disease | MESH | COVID-19 pandemic |
| disease | MESH | atopic dermatitis |
| disease | MESH | influenza |