Relaxation of COVID-19 restrictions coincided with increase in asthma exacerbations
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Adults with asthma experienced more exacerbations and acute respiratory infections after COVID-19 restrictions were relaxed, according to study results published in Thorax.
“The findings highlight the potential importance of public health measures like mask wearing/reduced social mixing for cutting risk of respiratory infections, which are the main triggers of asthma attacks,” Adrian Martineau, MRCP, PhD, clinical professor of respiratory infection and immunity at Barts and the London School of Medicine and Dentistry, Queen Mary University of London, told Healio. “Obviously clinicians can’t advise asthma patients to live in isolation, but there may be a benefit for these patients to wear a higher-protection (eg, FFP-2) face mask in indoor public places. That would need to be confirmed in a clinical trial, though.”
Using data from the longitudinal population-based COVIDENCE UK study, Martineau and colleagues analyzed 2,312 adults (mean age, 58.9 years; 75.3% women; 13.8% at least one severe asthma exacerbation 1 year before enrollment) with asthma in the U.K. between November 2020 and April 2022, none of whom had had COVID-19, to observe how relaxation of COVID-19 restrictions is associated with asthma exacerbations and acute respiratory infections (ARIs).
Using online questionnaires sent out monthly, researchers obtained information on frequency of face covering use, social mixing, incident ARIs and severe asthma exacerbations. Researchers then assessed temporal changes in these measures using Poisson generalized additive models, and they assessed the relationship between ARI and asthma exacerbations using multilevel logistic regression.
During follow-up, 17.8% of patients had at least one severe asthma exacerbation, 28.4% had at least one positive SARS-CoV-2 swab test result and 48.2% had at least one episode of ARI symptoms with a negative SARS-CoV-2 swab test result, according to researchers.
Based on the patient questionnaires, researchers found that relaxation of COVID-19 restrictions beginning in April 2021 coincided with less use of face coverings (P < .001), more social mixing with visits to indoor public places (P < .001) and more incidences of COVID-19 (P < .001), non-COVID-19 ARI (P < .001) and severe asthma exacerbations (P = .007).
However, when the omicron variant surfaced in the U.K. from December 2021 to January 2022, researchers observed more use of face coverings, less use of public transport and less frequent travel outside the country.
After adjusting for several sociodemographic and clinical confounder variables, researchers found that increased risk for asthma exacerbations was associated with incident non-COVID-19 ARI (adjusted OR = 5.75; 95% CI, 4.75-6.97) as well as with incident COVID-19 before the omicron variant surfaced in December 2021 (aOR = 5.89; 95% CI, 3.45-10.04) and after (aOR = 5.69; 95% CI, 3.89-8.31).
“These findings highlight the importance of vaccination against SARS-CoV-2 and influenza, as they underline the importance of respiratory infections in triggering asthma attacks (5-fold increase in odds),” Martineau told Healio. “There is also a degree of reassurance here, in that SARS-CoV-2 does not appear to be more likely than other infections to trigger asthma attacks.
“We need clinical trials to determine whether behaviors like wearing higher-protection masks can protect the wearer from catching respiratory infections that trigger asthma attacks,” Martineau added. “The data in this paper are observational — ie, we show temporal associations between reduced mask wearing and increased risk of infections, but we cannot draw a cause-and-effect conclusion as there are other factors that may also be in play — eg, reduced air pollution during lockdown that may have lessened risk of asthma attacks.”
For more information:
Adrian R. Martineau, MRCP, PhD, can be reached at a.martineau@qmul.ac.uk.