Table 1.

Heterogeneity of Asthma and Potential Risk of Severe COVID-19

Characteristic of Subject with Asthma	No Increased Risk of COVID-19 (or Decreased Risk)	Increased Risk of COVID-19
Age	Children and adolescents	Older subjects
Asthma phenotype	Type 2–high asthma	Type 2–low asthma
Airway gene expression	Type 2 cytokines (e.g., IL-13)	IFN-stimulated genes
Systemic inflammation	Low IL-6	High IL-6
Comorbidities	Allergic sensitization	Obesity, diabetes, or hypertension
Asthma severity	Mild-to-moderate asthma: GINA steps 1–4	Severe asthma: GINA step 5
Lung function	Normal	Impaired
Asthma control	Well controlled	Uncontrolled
Exacerbation frequency	No exacerbations	Frequent exacerbations
Controller treatment	ICS	OCS: repetitive bursts or OCS maintenance treatment

Definition of abbreviations: COVID-19 = coronavirus disease; GINA = Global Initiative for Asthma; ICS = inhaled corticosteroids; OCS = oral corticosteroids.