Background: Asthma exacerbations, a common reason for Pediatric
Emergency Department (PED) referral, can be triggered by multiple
factors, including infections, air pollution and allergens. Lockdown
measures and other public health interventions during the SARS-CoV-2
pandemic determined radical changes to behavioral and social habits,
that were reflected by a reduction in the transmission of all
respiratory pathogens and in the emissions of relevant air pollution
anthropogenic sources. Objective: This study aims to describe how
restrictions during SARS-CoV-2 pandemic impacted the PED referral for
asthma exacerbations and their potentially associated environmental
triggers in densely populated urban areas. Methods: PED referrals for
acute asthma from 2015 to 2020 were compared to air pollution and pollen
data. To this purpose, historical daily concentration records of PM2.5,
PM10 (including specific chemical tracers), as well as NO2, C6H6, tree,
grass and weed pollen were analyzed. Results: In 2020, asthma-related
PED referrals decreased up to 85%, compared to the average referral
rate of the previous 5 years (P<0.01). The drastic drop in PED
referrals was associated with a reduction of high-priority cases by
50-60%, unlike PED referrals for overall diagnoses, showing a larger
contribution for severe outcomes. A concomitant diminished contribution
of traffic-related air pollution was shown. Conclusions: The lower rate
of asthma exacerbations in childhood can be related to synergic
interactions of the multiple effects of lockdown measures which induced
lower viral infection rates and decreased exposure to outdoor allergens.
The reduction of traffic-related air pollution determined a weakening of
inflammatory properties of urban PM.
Understanding the environmental factors related to the decrease in Pediatric Emergency Department referrals for acute asthma during the SARS-CoV-2 pandemic
