The impact of the COVID-19 pandemic on respiratory morbidity during infancy: A birth-cohort study

Objective To evaluate the incidence of wheezing and overall respiratory morbidity in healthy infants born during the first peak of the coronavirus disease-2019 (COVID-19) pandemic, compared with infants born during the preceding year. Methods This was a single-center retrospective birth cohort study to compare a cohort of children born between February and March 2020 (COVID-19 group) to a control group of children born between February and March 2019 (pre-COVID-19 group). At 1 year of age, we collected respiratory data using parental and telephone questionnaires. Primary outcome: wheezing incidence and/or bronchodilator use. Secondary outcomes: recurrent wheezing, emergency-room visits, hospital admissions, pneumonia diagnosis, and admissions due to lower-respiratory-tract-infections (LRTI). We included the following covariate risk factors in the logistic regression models; atopy, daycare attendance, breastmilk feeding, parental smoking, C-section, siblings, and gestational age. Results We enrolled 588 infants, 294 in each group (48% males). Demographic, perinatal, and atopic characteristics were similar between the groups. Compared to the pre-COVID-19 group, infants born during the COVID-19 period were significantly less likely to report wheezing and/or bronchodilator use (adjusted-odds ratio [OR], 0.4; 95% confidence interval [CI] 0.28-0.59), systemic steroid use, (adjusted-OR, 0.47; 95% CI 0.24-0.91), emergency-room visits (adjusted-OR, 0.36; 95% CI 0.17-0.72), LRTI admissions (adjusted-OR, 0.2; 95% CI 0.05-0.74), or pneumonia diagnosis (adjusted-OR, 0.22; 95% CI 0.09-0.53). Conclusions This study investigated wheezing and respiratory morbidity over the first year of the COVID-19 pandemic in infants born during the first peak of COVID-19. The study demonstrated a significant decrease in most aspects of respiratory morbidity. A longitudinal follow-up study to explore the subsequent impact of these findings is warranted.