Is Asthma a Risk Factor for Coronavirus Disease-2019 Worse Outcomes?

The Answer Is No, But...

Priscila A. Franco; Sergio Jezler; Alvaro A. Cruz


Curr Opin Allergy Clin Immunol. 2021;21(3):223-228. 

In This Article

Management of Asthma and Allergic Rhinitis in Times of Coronavirus Disease

While managing patients with respiratory diseases in times of COVID-19, it is critical to identify those patients with comorbid conditions of risk of poor outcomes of COVID-19, such as diabetes, arterial hypertension and obesity, for a more careful evaluation, surveillance and early intervention, particularly among the elderly. It is essential, as well, to have a precise diagnosis of asthma and to optimize the management of patients with uncontrolled, difficult-to-treat and severe asthma, who may have a higher risk of worse outcomes, either because of the airway disease severity itself or because of the frequent requirement of systemic corticosteroids.[15] Patients with difficult-to-treat or severe asthma need high doses of inhaled controller therapy, which may be associated with risk of pneumonia, and are more vulnerable to exacerbations, having a higher risk of morbidity and mortality.[15]

A large study in the United Kingdom found that, overall, people with asthma are not at increased risk of COVID-19-related death. However, the risk of COVID-19 death was increased for people who had recently needed oral corticosteroids for their asthma.[16] Therefore, it is important to offer proper asthma management and improve adherence to treatment, with strategies to maintain good symptom control, reduce the risk of severe exacerbations and minimize the need for oral corticosteroids. Some reports have indicated having the asthma controlled may protect against complications of COVID-19, so that even patients using high doses of inhaled therapy with corticosteroids and biologic therapy, if controlled, may not have a worse prognosis. A large database analysis from Spain reports observations on 71 182 patients with asthma, 1006 (1.41%) of which have suffered from COVID-19. Patients with asthma and COVID-19 were older and at increased risk because of comorbidity-related factors. Inhaled corticosteroids and biologics were generally well tolerated and possibly associated with a protective effect against severe COVID-19 infection.[17] A report from France, describes observations on a cohort of patients hospitalized for COVID-19 (n = 768) having a history of asthma (n = 37). None of them presented with an asthma exacerbation. The conclusion is that asthma patients were not overrepresented among those with severe pneumonia because of SARSCoV-2 infection who required hospitalization. The worst outcomes were observed mainly in patients with other major comorbidities.[18]

The Global Initiative for Asthma (GINA) has advised patients with asthma must continue taking their prescribed asthma medications, including inhaled corticosteroids, and for the severe cases, oral corticosteroids and biologics during the pandemic, if required, as summarized in Table 1.[19] Oral corticosteroids may be used for exacerbations as needed. It advises the avoidance of nebulizers wherever possible, to reduce the risk of spreading viruses. Pressurized metered dose inhalers via a spacer are preferred except for life-threatening exacerbations. A mouthpiece or mask may be added to the spacer if required. The use of nebulization for patients who need beta-agonists in an emergency is commonly preferred by many emergency units but its use potentially increases the risk of aerosolization and as the nosocomial transmission of respiratory pathogens which is a major threat in the context of the SARS-CoV-2 pandemic. Early treatment of exacerbation in asthmatic patients with increased dose of maintenance therapy associated with rescue therapy and possibly oral corticosteroid, can help to ensure that patients are less likely to deteriorate to the stage when nebulizers or emergency units are needed. In case of asthma exacerbations because of COVID-19, one shall note that silent hypoxia ('Happy Hypoxemia') has been described, in which oxygen saturation is influenced and overestimated by respiratory alkalosis that often occurs in COVID-19 patients.[20] So far, it has been observed that asthma is associated with prolonged intubation, but it is not associated with higher mortality, when mechanical ventilation is required in patients infected with SARS-CoV2.[21]

Regarding biologics approved for asthma treatment, possible effects on the risk of COVID-19 may differ. However, omalizumab, mepolizumab, reslizumab, benralizumab, and dupilumab reduce asthma-related exacerbations and have all been approved for the treatment of severe asthma. Approximately 80% of asthma exacerbations are related to viral infections. Thus, these effects on overall exacerbations suggest that biologics used for the treatment of asthma may protect against virally exacerbated disease. This effect has been best established for omalizumab, which prevents IgE from binding to its receptor on plasmacytoid dendritic cells.[22]

With reference to allergic rhinitis, ARIA Initiative and the European Academy of Asthma and Clinical Immunology jointly recommend the regular use of intra-nasal corticosteroids in patients with chronic persistent allergic rhinitis, even when suffering from COVID-19 infection, as stopping the medication could result in more sneezing and increased spreading of the virus, in addition to the fact that exacerbation of allergic rhinitis might be confused with symptoms of COVID-19.[23]

It is noteworthy that adherence to treatment in patients with asthma and COPD during COVID-19 pandemic has increased.[24] The higher adherence to controller treatment among asthmatic patients seen during the pandemic may be one of the reasons why asthma has not been an important risk factor for worse outcomes of COVID-19 infection.