The Role of Coronavirus Disease 2019 (or Lack Thereof) in Asthma Exacerbations
Historically, seasonal coronavirus infection is associated with asthma exacerbations in children. However, previous coronavirus epidemics have not been associated with a risk of asthma exacerbations. For example, with SARS, also a novel coronavirus epidemic, the incidence in children was low and symptoms were predominantly mild with low morbidity and mortality. SARS did not induce bronchial hyper-reactivity nor cause eosinophilic inflammation and was not associated with an increase in asthma exacerbations.
In keeping with previous coronavirus epidemics, there is actually some basis to suggest that children with atopic asthma may be at reduced risk of asthma exacerbations during COVID-19. A retrospective review of 212 children with confirmed atopic asthma in Spain found that, compared with those children with asthma who did not develop COVID-19, those who did had no significant difference in asthma treatment, lung function, asthma severity or asthma control. In fact, families did not report any worsening of symptoms compared with a similar time period in the previous year among the atopic children with asthma who developed COVID-19. During the first 5 weeks of the lockdown in Slovenia, there was a 71–78% decrease in pediatric asthma admissions compared with the same time periods in the last 3 years. At a large US tertiary care center during the spring of 2020, a 76% reduction in asthma emergency department (ED) visits was noted, with similar trends for children of all levels of acuity. The percentage of children with asthma subsequently admitted to the hospital also decreased (from 31 to 22%). Electronic health records from Children's Hospital of Philadelphia found that, compared with the 5 previous years, in-person asthma encounters decreased by 87 (outpatient) and 84% (emergency and inpatient), and asthma-related systemic steroid prescriptions decreased. A study of pediatric patients with asthma treated in the Children's Hospital of Orange County found 78, 90, 68% reductions in hospitalization, ED visits and asthma exacerbations, respectively, compared with pre-COVID-19 2020, and significant reductions in albuterol and inhaled corticosteroid use (P < 0.05). A retrospective chart review of children utilizing the pediatric ED in the Bronx from March to June 2020 found a significant reduction in asthma-related ED visits (P < 0.0001). While not specific to children, a cohort from a US database of healthcare claims for over 200 million privately insured patients found a significant decline in asthma exacerbations after the COVID-19 pandemic onset (P < 0.001).
It is possible that public health measures resulting in masking, reduced viral transmission, reduced outdoor aeroallergen exposure, reduced traffic/industrial pollution, and improved air quality overall are contributing to the reduction in asthma exacerbations. During the first spring of the pandemic in Slovenia, when a dramatic reduction in asthma exacerbations was noted, there was also a 51–58% decrease in admissions for acute respiratory tract infections and a 48–58% reduction in the air nitrogen dioxide level [although concentrations of particulate matter with a diameter of less than 10 micrometers (PM10) did not change substantially]. The Children's Hospital of Orange County study found a significant reduction in PM2.5 and influenza rates during the pandemic, as well as increased use of telehealth resources which may serve previously under-accessed populations (with greater use in the publicly insured group compared with the commercially insured group). Other possibilities include that patients and their families are avoiding seeking care during the pandemic, and/or that the pandemic has led to improved compliance with asthma medications.
Curr Opin Allergy Clin Immunol. 2022;22(2):95-100. © 2022 Lippincott Williams & Wilkins