ACE2 expression in allergic airway disease may decrease the risk and severity of COVID-19

At the start of the COVID-19 pandemic, allergic rhinitis, allergy, asthma, and chronic obstructive pulmonary disease were considered risk factors because they tend to aggravate during respiratory viral infections and upper respiratory tract symptoms viral infections, allergic rhinitis, and influenza overlap during COVID-19 early stages. This review aimed to revise recent studies published that do not prove that allergy and asthma are risk factors or increase severity for COVID-19.

Recent literature has not shown that airways allergic diseases are a high-risk factor or increase the severity of COVID-19. The reason is that there is a reduction in angiotensin-converting enzyme 2 (ACE2) gene expression in the nose and bronchial cells of allergic airway diseases.

Low ACE2 expression in airway cells of individuals with allergic rhinitis and allergic asthma decreases their susceptibility to COVID-19 and may not be a risk factor for severe infection. However, this is not true for the nonatopic asthma phenotype. More studies are needed to understand the impact of respiratory allergic diseases and T2 inflammatory response on COVID-19 severity and susceptibility. It is essential to continue asthma and allergic rhinitis treatments with inhaled corticosteroids, biologics, and allergen immunotherapy during the COVID-19 pandemic.