Why asthma might surprisingly protect against poor outcomes in COVID-19

We read with interest the study by Beurnier et al. [1] describing a lower prevalence of asthma (4.8%) in a cohort of 768 patients hospitalised with coronavirus disease 2019 (COVID-19) compared to the general population, none of whom presented with an asthma exacerbation and only one who was treated for bronchospasm. This subgroup also had significantly reduced mortality compared to a control group without asthma. These findings must be considered preliminary given that they arise from a relatively small, single-centre cohort. In particular, the control group differed significantly in age (older) and gender balance (greater male/female ratio); both characteristics are associated worse outcomes and this raises the possibility that the results represent a statistical artefact. Asthma may protect against poor outcomes in COVID-19 due to several possible mechanisms, including altered viral entry receptor expression, inhaled corticosteroid use, chronic inflammation, reduced exposure due to shielding and/or mucus hypersecretion https://bit.ly/3eiXOPP