COVID-19 and asthma: Much remains unknown
Viral-induced asthma exacerbations are common, but there has yet to be a published data set showing worse outcomes among asthmatics with COVID-19.
It is possible that inhaled corticosteroids (ICS) may provide some protection from viral infection. A 2014 study showed that ICS may reduce exacerbations by modulating inflammation and reducing airway viral receptors (Yamaya, et al.). Analysis from the SARP-3 database showed ICS use associated with reduced expression of both ACE2 and transmembrane protease serine 2 (TMPRSS2), two receptors used by SARS-CoV-2 (Peters, et al. Am J Respir Crit Care Med. 2020. Online ahead of print). Another study showed a similar effect of ICS on the seasonal coronavirus strain HCoV-229E (Yamaya M, et al. ), and one study reported decreased ACE2 expression in allergic asthma (Jackson, et al. J Allergy Clin Immunol. Article in press, 2020). While these findings could support a hypothesis of reduced risk for COVID-19 infection among asthmatics using ICS, one would generally expect those with underlying lung disease, such as asthma, to be at higher risk for more severe infection.
Despite physiologic hypotheses of protective mechanisms, clinical outcomes may suffer as clinical operations and the American economy are impacted by this pandemic. Reduced access to or utilization of outpatient care, loss of employment, loss of health insurance, or a new difficulty in affording or accessing medications may all result in worsening asthma control for patients. Poorly controlled asthmatics are at higher risk for a more severe exacerbation of disease triggered by viral infection. Current recommendations are for patients to continue all controller medications; the use of systemic corticosteroids in treatment of COVID pneumonia is controversial, but their use in treating a COVID-associated asthma exacerbation should be based on individual assessment. As we care for asthma patients through this pandemic, much remains unknown but may be elucidated by further study.
Megan Conroy, MD
Muhammad Adrish, MD, FCCP
Steering Committee Member