At the onset of the COVID-19 pandemic, public health officials warned that those with asthma might be especially vulnerable to the rapidly spreading respiratory virus. But new research suggests that people with asthma suffered less severe infections and mortality than those without the lung disease.
Prior studies support that advanced age, obesity, and diabetes are risk factors for experiencing severe COVID-19 outcomes. But while physicians also encouraged those with chronic airway diseases like asthma and chronic obstructive pulmonary disease (COPD) to take extra precautions against COVID, this approach lumped people with very different lung conditions together and failed to consider variability in outcomes across patient groups. Now, one of the largest analyses to date of patients with chronic airway diseases and COVID-19 has found that while those with COPD were at a higher risk of severe infection during the first two waves of the pandemic, by contrast those with asthma showed better health outcomes than the general population. The authors published their findings in The Journal of Allergy and Clinical Immunology: In Practice on July 14.
“Our findings suggest that there may be a mechanism intrinsic to having asthma that actually may allow these patients to handle the virus better than a healthy individual,” says Geoffrey Chupp, MD, professor of medicine (pulmonary, critical care, and sleep medicine) at Yale School of Medicine and principal investigator of the study. Chupp is also the director of the Yale Center for Asthma and Airways Disease.
In 2020, Chupp admitted one of the first patients with asthma and COVID-19 into the intensive care unit at Yale New Haven Hospital. “From the moment COVID hit, I was struggling to figure out what to say to my patients and how to counsel them about the risks of COVID-19." Unexpectedly, Chupp started to notice that his patients with asthma and COVID-19 tended to have successful recoveries post-infection. But there was little existing research to support what he was seeing in the clinic.
Risk of Severe COVID-19 is Heightened by COPD But Lessened by Asthma
In their latest study, Chupp’s team used Yale’s electronic health record to identify more than 8,000 patients who were hospitalized with COVID-19 between March 2020 and April 2021. The researchers organized these patients into four groups based on their diagnostic codes: asthma, COPD, asthma plus COPD, and no airway disease. For each of the groups, they used patient sequential organ failure assessment (SOFA) scores to track the severity of COVID-19 infection over the course of hospitalization, and also looked at mortality across cohorts. The team adjusted their analyses to account for factors known to influence COVID-19 outcomes including age, sex, comorbid diseases, and race, and ethnicity.
The study found increased severity of COVID-19 in patients with COPD compared to the control group, but lessened severity in patients with asthma. Patients with both asthma and COPD experienced outcomes similar to those without a chronic airway disease. “This indicates a potential counterbalancing of the effects between asthma and COPD,” explains Yunqing Liu, PhD, who was first author of the paper.
Next, the team considered counts of eosinophils, white blood cells associated with allergic inflammation that can be associated with chronic lung disease. Their findings revealed that higher eosinophil counts and inflammation were significantly correlated with better health outcomes in all the patient groups, and especially for those with asthma. Intrigued, the researchers conducted a further analysis adjusting for eosinophil count and found that the improved outcomes in patients with asthma persisted. Thus, while this immune response may explain some of the improvement seen in this group, it does not tell the full story. “Our work demonstrates that we need to precisely understand a patient’s underlying airway disease to properly educate them about the risks of severe COVID,” Chupp says. That education includes distinguishing between asthma and COPD.
Chupp hopes this work will inspire future studies that explore the mechanisms underlying this boosted protection so that researchers may better understand how to help patients infected with SARS-CoV-2. In the meantime, patients with asthma should be reassured that they are not at an increased risk of severe infection. Still, Chupp encourages all patients to seek medical advice if they begin experiencing COVID-19 symptoms and get vaccinated if they haven’t already. “COVID is here to stay, and it’s going to continue to cause illness,” says Chupp. “So it’s important for public health advisories to be specific about the risks for those with airway diseases.”