Risk of Severe COVID May Hinge on Type of Asthma
Grayson agrees with Khurana that in the early days of the COVID-19 pandemic, there were great concerns that asthma could be a risk factor – a reasonable suspicion, given that the coronavirus attacks the lungs.
But everything that came out of the initial outbreak in China suggested asthma was not a life-threatening COVID risk factor, Grayson said, and the data continued to confirm this as the coronavirus spread across the world.
“It’s not there in the data. If it’s there, it’s extremely low risk. It’s nothing I can see,” he said.
Researchers have speculated that people with allergic asthma may have some protection against COVID, due to the way the coronavirus infects the body.
The SARS-CoV-2 virus that causes COVID-19 enters lung cells by engaging with a type of protein on their surface called the ACE2 receptor, Khurana said.
“In allergic-type inflammation, the expression of the ACE2 receptor appears to be downregulated. It appears to be lower. There is not as much receptor,” she said.
Since there aren’t as many ACE2 receptors available, people with allergic asthma might not be as vulnerable to serious infections, Khurana said. This theory could also help explain why other chronic diseases appear to increase the risk of COVID, she added.
“Patients with conditions like diabetes or hypertension, this receptor expression is increased,” Khurana said. “This is a possible reason why these concomitant diseases pose a particularly high risk of contracting this infection.
But that only explains why allergic asthma is not a major risk factor for severe COVID, Grayson said. This does not explain why some studies show an increased risk in people with non-allergic asthma.
Grayson suspects that the alleged link between non-allergic asthma and COVID found in these studies is actually a link between COVID and a host of different lung conditions, especially COPD.
“There are studies showing that COPD increases your risk of more severe COVID, not significantly but somewhat, not to the extent of things like hypertension and diabetes and [being] “I’m concerned that what they call non-allergic asthma is actually COPD, which would skew their data.”
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