Coronavirus disease 2019 (COVID-19) is an infectious respiratory illness caused by the SARS-CoV-2 virus and is considered a pandemic in over 120 countries worldwide. Seniority, race, sex, comorbidities, and living situations were all indicated as risk factors for severe COVID-19. Although asthmatics and individuals with allergies were more likely to have catastrophic consequences from viral infections, COVID-19 has not been documented to have substantial comorbidity. However, there were also contradicting studies about the effect of asthma on COVID-19. These findings had partly been explained by the underlying immunological and molecular pathways. Furthermore, COVID-19 was affected by environmental variables such as air pollution, which negatively influences asthma and respiratory disorders.
The receptor for SARS-CoV-2 attachment and entrance into host cells, angiotensin-converting enzyme 2 (ACE2), was increased by Th1-mediated responses. ACE2 gene expression was frequently lower in asthmatics. Researchers found a negative association between ACE2 expression and levels of Th2 cytokines such as IL-4, IL-5, and IL-13 in airway epithelial cells and other types 2 biomarkers. Asthma’s putative protective function against COVID-19 may be explained in part by this. Researchers discussed the relationship between respiratory viral infections and asthma, the immune-molecular processes of SARS-CoV-2 disease, the influence of asthma on COVID-19 and SARS-CoV-2 on asthma and allergic rhinitis, and the impact of environmental variables on COVID-19, such as air pollution.
The inflammatory profile influences the expression of ACE2 in SARS-COV-2 airway epithelial cells. Respiratory allergy disorders, such as asthma appeared to protect against SARS-COV-2 infection. However, the clinical relationship between asthma and SARS-COV-2 has not been well established.