Asthma is not a risk factor for a severe course of COVID-19

Asthma needs to be kept under control

Although it might seem that asthma as a chronic respiratory disease could worsen the course of coronavirus pneumonia, it holds true that if the disease is well-controlled, lung function is normal, and the patient is long-term without exacerbations and acute attacks, asthmatics do not have a higher risk of severe COVID-19 lung infection than those without asthma. However, as noted by pediatric pulmonologist and director of the Czech Initiative for Asthma Prof. MUDr. Petr Pohunek, CSc., „the condition is that asthmatics follow the prescribed treatment regimen, prescribed doses of medications, and of course, preventive protective measures“.

Asthma treatment should continue diligently

Anti-inflammatory medications, most often inhaled corticosteroids, play a primary role in asthma treatment. There have been reports that corticosteroids can worsen the course of COVID-19. However, this concerns systemic corticosteroids, not inhaled ones, even in prescribed higher doses.

If a patient with asthma is using systemic corticosteroids for severe asthma, they must not be suddenly discontinued. Also, systemic corticosteroids should not be newly initiated in asthmatics due to the onset of COVID-19.

All other medications in asthma therapy should still be administered diligently and with the correct application technique, according to the Czech Initiative for Asthma. Discontinuing medications due to fears of weakening immunity is not justified and can lead to significant complications.

The absence of increased risk is due to reduced ACE2 receptor expression

In Chinese patients with COVID-19, asthma and respiratory allergies were not identified as significant risk factors for a severe course of the illness. The SARS-CoV-2 virus uses ACE2 receptors to enter cells. Increased expression of these receptors has been found in smokers and patients with diabetes or hypertension, conditions associated with a higher risk of severe COVID-19.

The authors of a recently published study tested the hypothesis that the absence of increased risk in individuals with asthma and respiratory allergies is due to reduced ACE2 receptor expression. Tests were conducted on a cohort of 318 children at risk of developing asthma within the URECA (Urban Environment and Childhood Asthma) study and two cohorts of adult patients with 24 and 23 probands, respectively. They demonstrated that respiratory allergy is associated with a significant reduction in ACE2 expression. The lowest expression was found in individuals with a high degree of allergic sensitization and asthma. They also note that the body's response to SARS-CoV-2 infection in patients with respiratory allergies is very likely influenced by other factors.

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Sources:
1. Czech Initiative for Asthma. Coronavirus SARS-CoV-2 does not threaten asthmatics more than the general population, but it is important to adhere to the treatment. ČIPA, April 2020.
2. Could asthma and allergy protect against severe COVID-19? Reuters Health Information, 2020 Apr 30.
3. Jackson D. J., Busse W. W., Bacharier L. B. et al. Association of respiratory allergy, asthma, and expression. J Allergy Clin Immunol 2020 Apr 22; S0091-6749(20)30551-0, doi: 10.1016/j.jaci.2020.04.009 [Epub ahead of print].