Atopic Disease Does Not Increase Risk for Severe COVID-19

Ingrid Hein

November 14, 2020

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

COVID-19 is no more severe in patients with allergy and asthma than in those without these conditions, new research reveals.

"My patients will certainly be relieved," said Dylan Timberlake, MD, from Nationwide Children's Hospital in Columbus, Ohio.

Early in the pandemic, a statement warning that people with allergy and asthma were at elevated risk for severe coronavirus disease was issued by the Centers for Disease Control and Prevention. However, the basis for that warning was a study of people "infected with other respiratory viruses, not COVID-19," Timberlake told Medscape Medical News.

"At the time, it was the best information" available, he said.

Then, in August, a retrospective study showed that atopic disease has a protective affect against COVID-19.

Still, "we had to tell our patients to take extra precautions; that we didn't have enough data one way or another," said Timberlake.

But indications that atopic disease is protective have increased over time, "so we went into our study with an open mind," he explained at the American College of Allergy, Asthma & Immunology (ACAAI) 2020 Annual Scientific Meeting.

For their retrospective review, Timberlake and his colleagues assessed the charts of 275 patients who tested positive for SARS-CoV-2 and were admitted to the Nationwide Children's Hospital or to the Ohio State University Wexner Medical Center from March 1 to May 5.

Because only 13 pediatric patients were identified, their data were pooled with the adult data.

A total of 91 patients reported atopic disease — including asthma, atopic dermatitis, allergic rhinitis, and food allergy — but only 67 patients had a diagnosis documented. The majority of those — 60 patients — had a documented diagnosis of asthma.

"We know that food allergy and allergic rhinitis are over-reported, so we confirmed that patients had allergist blood testing or skin tests," Timberlake said.

Adjustment for COPD

COPD — a known variable for severe coronavirus disease — was more common in the 67 patients with atopic disease than in the 208 without (38.8% vs 17.3%; P < .001).

"COPD is a confounding condition," Timberlake confirmed.

The mortality trend was lower in patients with atopic disease than in those without, after adjustment for COPD (odds ratio [OR], 0.55; 95% CI, 0.23 - 1.28; P = 0.16), but overall, outcomes were similar in the two groups.

Outcomes in Hospitalized COVID-19 Patients With and Without Atopic Disease
Outcome Atopic Disease, % No Atopic Disease, %
ICU admission 43.0 44.7
Oxygen use 79.1 73.0
Intubation 35.8 36.5
Mortality 13.4 20.7

"There was no evidence of severe disease, and no evidence of protection," said Timberlake. "It doesn't look like having asthma or allergies puts you at any increased risk."

"We think that if we control for obesity, we might find that atopic disease offers some level of protection," he reported, explaining that the team plans to continue studying the data, with adjustment for that potential confounding factor.

Decreased ACE2 Potentially Protective

Atopic disease could very well have a protective effect, said ACAAI spokesperson Kevin McGrath, MD, from Wethersfield, Connecticut.

A recent Italian study showed that atopic disease offers protection from severe COVID-19 because of the angiotensin-converting enzyme 2 (ACE2).

"Patients with asthma and allergies have fewer ACE2 receptors in their lungs genetically," McGrath told Medscape Medical News. "This should put them at lower risk for having a severe outcome, as the COVID virus attaches to the ACE2 receptors," leading to pneumonia.

Patients taking inhaled steroids for asthma also have fewer ACE2 receptors in their lungs, "which may offer protection," he added. And "members of the American College of Allergy, Asthma & Immunology are not seeing worse outcomes in allergy and asthma patients."

A recent ACAAI press release cites yet another study that has shown that there is no association between asthma and risk for hospitalization after infection with the virus.

Timberlake and McGrath have disclosed no relevant financial relationships.

American College of Allergy, Asthma & Immunology (ACAAI) 2020 Annual Scientific Meeting: Poster P350.

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