Children born during COVID-19 pandemic lockdowns had fewer wheezing episodes and used less respiratory medication than those born before 2020, according to a research letter posted today in JAMA Network Open.
A University of Padua-led research team in Italy led a retrospective study comparing rates of wheezing and use of respiratory medicines in children born from February to April 2020 (lockdown cohort) with those in peers born during the same months in 2016 and 2017 (historical cohort). The children were enrolled in Pedianet, a database of 150 family pediatricians in Italy, and followed for 30 months.
"During the COVID-19 lockdown, bronchiolitis nearly disappeared," the study authors noted. "Bronchiolitis, caused by respiratory syncytial virus (RSV) in 50% to 80% of cases, is a recognized risk factor for wheezing illnesses and asthma."
9% of lockdown group wheezed vs 15% prepandemic
In total, 2,192 and 3,889 babies were born during the lockdown and historical periods, respectively. There were no differences in sex, area deprivation index score, gestational age, or family history of atopic (allergic) disease.
During the follow-up period, 9.4% of children in the lockdown cohort had at least 1 wheezing episode, compared with 15.0% in the historical cohort. Rates of wheezing episodes were 67.6 per 10,000 person-months during lockdowns and 110.0 per 10,000 during the historical period. The lockdown cohort had few (6.6 per 10,000 person-months) bronchiolitis cases, versus 82.4 per 10,000 before the pandemic.
This study underscores the potential role of a universal RSV immunoprophylaxis in preventing postbronchiolitis wheezing.
Thirty-month cumulative wheezing incidence curves revealed a significant difference between cohorts, which was confirmed at 45 months with a cumulative wheezing risk of 16% prepandemic and 13% during lockdowns.
The risk of wheezing fell 44% in children amid lockdowns, with an estimated 30% of episodes eliminated by COVID-19 public health measures alone, assuming bronchiolitis had no other positive link to wheezing risk (hazard ratio [HR], 4.43), the authors said.
The lockdown group received fewer nebulized β2 agonists (5.1 vs 7.9 per 1,000 person-months) and nebulized glucocorticosteroids (19.5 vs 23.5 per 1,000) than the historical group.
"In line with a large birth cohort study demonstrating that not being infected with RSV during the first year of life is associated with a 26% lower risk of 5-year current asthma, this study underscores the potential role of a universal RSV immunoprophylaxis in preventing postbronchiolitis wheezing," the researchers wrote.
