Asthma and severe acute respiratory syndrome coronavirus 2019: current evidence and knowledge gaps

Abstract

Purpose of reviewAlthough respiratory viruses are common triggers of asthma exacerbation, it is unknown whether this also applies to infection with SARS-CoV-2. Indeed, patients with asthma and allergy appear underrepresented in large reports of COVID-19 cases worldwide. In this review, we evaluate existing literature on this topic and potential underlying mechanisms for any interrelationship between asthma and COVID-19. Recent findingsData from several preclinical and clinical reports suggest a lower susceptibility for COVID-19 in patients with underlying type 2 airway inflammation including asthma that may be related to a reduced expression of ACE2 and TMPRSS2 receptors for SARS-CoV-2. Corticosteroids further decrease expression of the ACE2 and TMPRSS2 receptors, hence may also have a protective effect against infection with SARS-CoV-2. In addition, some studies suggest that the reported improvement in asthma control and a reduction in asthma exacerbations during the COVID-19 pandemic may be related to improvement in adherence to controller therapy and reduced exposure to triggers, such as other respiratory viruses and air pollutants. Recent data point towards differential susceptibility for COVID-19 among asthma patients based on their phenotype and/or endotype. On the basis of existing evidence, continuation with controller therapies is recommended for all patients with asthma. For patients with severe uncontrolled asthma infected by SARS-CoV-2, adjustment of controllers and biologics should be based on a multidisciplinary decision.

Impact of bronchiectasis on susceptibility to and severity of COVID-19: a nationwide cohort study

“…Interestingly, COVID-19 patients with bronchiectasis showed a significantly higher prevalence of COPD (57.6% versus 19.3%) and asthma (62.1% versus 17.2%) than the overall population with bronchiectasis in South Korea. 10 Although asthmatics were suggested to be protected from COVID-19, 12 this study showed significantly higher asthma rate in COVID-19 patients with bronchiectasis than those without bronchiectasis. Bronchiectasis may serve as a leverage to more severe COVID-19 in asthmatics; however, future research is necessary to clarify the mechanistic link.…”

Symptoms in patients with asthma infected by SARS-CoV-2

“…Recent data suggests differing susceptibility to COVID-19 among asthma patients based on their phenotype, with a lower susceptibility in patients with underlying type 2 airway inflammation [ 3 ]. In our series, wheezing was significantly more frequent in the non-T2 phenotype.…”

“…However, the organ tropism of SARS-CoV-2 to the respiratory tract could potentially aggravate asthma. In fact, although respiratory viruses are common triggers of asthma exacerbation, it has not yet been established whether this also applies to SARS-CoV-2 infection [ 3 ]. The susceptibility of patients with asthma to develop an exacerbation when they are infected with SARS-CoV-2 is unknown.…”

Asthma and COVID-19: a dangerous liaison?

“…Epidemiological studies of COVID-19 must include detailed information on asthma comorbidity and prior medication to help answer these questions [125]. Today, there is no evidence of an association of increased risk of COVID-19 infection in asthmatic patients regularly taking ICSs [126]. Asthma exacerbations have been markedly reduced especially in children during the COVID-19 pandemic, which may not only be due to a decrease in exposure to triggers, i.e.…”

“…In hospitals, the use of metered-dose inhalers (MDIs) and dry powder inhalers (DPI) is preferred to nebulizers if patients can perform the breathing maneuvers. If a nebulizer is used, a high-flow nasal cannula is preferable to a face mask and a mouthpiece should be used with a jet or mesh nebulizer, and viral filters or one-way valves should be attached to nebulizers to minimize the release of aerosols [126].…”