Asthma, Severe Acute Respiratory Syndrome Coronavirus-2 and Coronavirus Disease 2019

Dylan T. Timberlake; Kasey Strothman; Mitchell H. Grayson


Curr Opin Allergy Clin Immunol. 2021;21(2):182-187. 

In This Article

Coronavirus Disease 2019 Clinical Disease

The clinical course of COVID-19 has been described to occur in three phases with progression not occurring in all patients: an asymptomatic incubation phase, a second nonsevere symptomatic phase, and a tertiary severe respiratory disease phase.[8] This tertiary phase of severe respiratory disease is secondary to significant lung inflammation with ARDS.[9] The etiology of ARDS in COVID-19 is felt to be due to an over-exuberant inflammatory response caused by a release of IFN-α, IFN-γ, TNF-α, Il-1β, Il-6, Il-8, Il-12, and Il-18 cytokines, referred to as 'cytokine storm'.[10] The severity of this tertiary phase correlates with the degree of inflammation, demonstrated by the positive correlation between severe disease with COVID-19 and blood levels of Il-6 and CRP.[11,12] Risk factors for a more severe clinical disease may be better understood by taking into consideration the mechanism of action of the virus at a cellular level.