Asthma and Its Covid-19 Risks (or Not)

Updated 02/09/2021

Common asthma treatment reduces need for hospitalization in COVID-19 patients, study suggests

Without much ado, I'll refer you to read [1] to understand Asthma (see also the infographic provided in this article).

Figure 1.  Endothelial dysregulation by SARS-CoV-2. ^[5]

What's ACE2 Receptor?

The SARS-CoV-2 virus that causes COVID-19 enters lung cells by engaging with a type of protein on their surface called an ACE2 receptor.  Normally, this cell-surface receptor functions to regulate blood pressure, but SARS-CoV-2 has co-opted it as a means to gain entry into cells in the lungs and other organs. 

Patients in conditions like diabetes or hypertension, this receptor (i.e., ACE2) expression is increased. That's a possible reason why those comorbid diseases are at especially high risk for this infection.^[4]

Allergy-driven asthma vs non-allergic asthma

Allergy-driven asthma

"In the setting of an allergic type of inflammation, the expression of the ACE2 receptor appears to be downregulated. It appears to be lower. There's not as much receptor," Dr. Sandhya Khurana said.[4]

Because there aren't as many ACE2 receptors available, people with allergic asthma might not be as vulnerable to severe infection, Khurana said.

Non-allergic asthma

Some studies have suggested that people who have asthma (or non-allergic asthma) caused by something other than allergies -- exercise, stress, air pollution, weather conditions -- might have an increased risk of severe COVID-19.

However, their asthma could be caused by other lung ailments (e.g., COPD) that are associated with more serious cases of COVID, for instance, said Dr. Mitchell Grayson.

Everything that came out of the initial epidemic in China suggested that asthma was not a risk factor for life-threatening COVID, Grayson said, and the data continued to confirm that as the coronavirus spread across the globe.

Wrap It Up

The CDC^[3] does list moderate-to-severe asthma as a possible risk factor for severe COVID-19 disease, but there are no published data to support that at this time.

 "It's good practice to observe the recommended guidance on hand hygiene and social distancing and masking and avoiding any situation where you could be exposed, even though it's obviously welcome to see that allergic asthma is not as high-risk as some of the other comorbid diseases," Khurana said.

Image via: ShapeAble

References

1. Understanding Asthma 
2. Rosenthal JA, Awan SF, Fintzi J, Keswani A, Ein D. Asthma is associated with increased risk of intubation but not hospitalization or death in COVID-19. Published online October 12, 2020. Ann Allergy Asthma Immunol. doi:10.1016/j.anai.2020.10.002
3. People with Certain Medical Conditions (CDC)
4. Risk of Severe COVID May Hinge on Type of Asthma
5. Endothelial dysfunction in COVID-19: a position paper of the ESC Working Group for Atherosclerosis and Vascular Biology, and the ESC Council of Basic Cardiovascular Science
6. Inhaled budesonide in the treatment of early COVID-19 illness: a randomized controlled trial