After COVID-19 pandemic protocols were put into place, asthma exacerbations decreased and were lower than during the prior year through May 2021.


It has been anecdotally observed that severe asthma (SA) exacerbations have decreased following the implementation of COVID-19 protocols such as social distancing and exposure avoidance, explains Wendy C. Moore, MD. Since the impact of the COVID-19 pandemic on asthma exacerbations and hospitalizations in adults has not been well-documented, Dr. Moore and colleagues analyzed asthma exacerbation rates in the longitudinal CHRONICLE Study to gather and evaluate observational information on patients with SA before and during the pandemic. The study was published in the Journal of Asthma and Allergy.

Dr. Moore shared her concerns when the pandemic began. “As asthma specialists, many of us were quite worried that our patients would have high morbidity and mortality associated with the COVID pandemic,” she says. “For years, coronaviruses have triggered SA exacerbations in our patients, sometimes requiring ED visits and hospitalizations, so we were very concerned about a new coronavirus.”

COVID-19 Did Not Lead to Increased Asthma Exacerbations

What Dr. Moore and other specialists observed was that “COVID-19 turned out to be quite different from past coronaviruses and did not lead to increased asthma exacerbations. The decrease in asthma exacerbations was likely multifactorial—asthma patients staying home as advised and wearing masks because they were afraid of a circulating respiratory virus given their underlying respiratory disease. In general, they reported no (or very few) respiratory illnesses that are typically a trigger for an asthma exacerbation. Many of my patients will opt to continue to mask in public because they didn’t get the common cold during the pandemic.”

The CHRONICLE Study is a continuing noninterventional observational investigation of 3,100 subspecialist-treated patients with SA. Participants consist of adults who meet one of the following criteria: are taking an FDA-approved monoclonal antibody therapy for SA, use maintenance systemic corticosteroid or other systemic immunosuppressants for at least 6 of the past 12 months, or have persistently uncontrolled asthma while being treated with high-dosage inhaled corticosteroids with additional controllers.

Decreased in Asthma Exacerbations Has Led to Improved Asthma Control

The study found that in April 2020, after pandemic protocols were put into place, asthma exacerbations decreased and were lower than they were during the prior year through May 2021 (Figure). “The decrease in asthma exacerbations during the pandemic has led to improved asthma control in many of our most patients with SA,” Dr. Moore says. “As working remotely and universal masking comes to an end, asthma exacerbations will likely increase again.”

Dr. Moore cautions practitioners about the application of this information. “When making decisions about therapy including starting biologic therapy, physicians need to understand that the past 2 years will not be predictive of poor asthma outcomes and control going forward,” she says. “While asthma exacerbations decreased in all the patient groups in our study, patients with SA on biologic therapy had the lowest baseline asthma exacerbation rate and thus, had the lowest exacerbation rate during the pandemic. Lack of asthma exacerbations in the past 2 years should not exclude patients from consideration for biologic therapy if indicated.”

Vaccine Innovation May Lead to Vaccines for Other Respiratory Illnesses

More work is needed in this field of study, Dr. Moore notes. “This study exemplifies the power of preventing all respiratory illnesses (not merely COVID-19) driven by viruses on asthma exacerbation rates,” she says. “In this situation, which was accomplished by isolation and universal masking—ie, removing the patients from virus exposure—which is not compatible with regular life.

Research into further vaccines to prevent the portfolio of respiratory viral illnesses is needed. “The leap in innovation with RNA-based vaccines has created the possibility of vaccines for other viruses that cause respiratory illnesses in at-risk patients,” Dr. Moore says. “Patients with SA would benefit immensely from not getting viral infections as seen in our study.”