Respiratory Morbidity Before and During the COVID-19 Pandemic From Birth to 18 Months in a Swedish Birth Cohort
Year: 2025
Type: conference-abstract
Abstract: This study aimed to investigate the incidence of respiratory illness and aeroallergen sensitization in young children born either before or during the COVID-19 pandemic.Two groups of Swedish children were included from population-based birth cohorts: 1661 children born between March 2020 and April 2021 (the COVID-19 group) and 1676 children born between May 2016 and August 2018 (the pre–COVID-19 group). In total, 3337 children were analyzed, with 1702 (51.0%) participating in a serology substudy based on parental consent for venipuncture, including 849 pre-COVID and 853 COVID. Of note, Sweden’s COVID-19 restrictions did not include forced quarantines for household members, masks were not recommended outside of the health care setting, and nursery schools (up to age 6 years) and schools for children up to age 16 years remained open, whereas upper secondary schools and universities practiced distance learning.This was an observational study using prospectively collected data from before and during the COVID-19 pandemic. Information was gathered via parent-completed questionnaires and national medical registries. Allergen-specific immunoglobulin E levels were measured at age 18 months.Children born during the COVID-19 pandemic had a decreased risk of wheeze, respiratory tract infections, bronchitis, and croup within the first 18 months of life. They also had reduced wheeze during the first 9 months and decreased antibiotic use compared with the pre-pandemic cohort. Aeroallergen sensitization rates were similar between both groups. Furthermore, the percentage of babies at age 9 months with no reported common cold symptoms was 5.7% in the COVID cohort compared with 26.6% in the pre-COVID cohort. The percentage of babies at age 9 months with no reported common cold symptoms was 5.7% in the pre-COVID cohort compared with 26.6% in the COVID cohort.Children born during the COVID-19 pandemic experienced a lower risk of respiratory infections and prescribed antibiotics until age 18 months, whereas rates of aeroallergen sensitization remained unchanged.The COVID-19 pandemic provided a unique opportunity to assess the effects of widespread infection-prevention measures on respiratory illnesses and allergic sensitization in early childhood. This study supports prior findings of reduced respiratory infections during the pandemic and accounts for potential confounders and effect modifiers. As expected for this age group, few children demonstrated laboratory evidence of allergic sensitization at 18 months. There was a lower prevalence of wheeze at age 9 months during the COVID cohort, but that difference was mitigated by age 18 months. Of note, participants in this study were from a specified geographic area, which may limit the generalizability of these findings, and as mentioned above, Sweden had unique COVID precautions compared with other countries. The COVID pandemic may also influence the manner in which many individuals view illness and the health care system, which can skew parent-reported symptoms and the likelihood to present to care. Continued longitudinal follow-up of these cohorts will be valuable in assessing long-term risks of allergies and asthma. Such research may help clarify the complex relationship between early-life viral infections and allergic disease development, which remains uncertain—particularly regarding whether infections have a protective or detrimental effect on later allergic outcomes.
Source: PEDIATRICS
Language: English
Subfield: Physiology
Field: Medicine
Domain: Health Sciences
Open Access status: bronze
OpenAlex ID: W4416832629
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