Ambient air pollution is associated with respiratory infection burden in the first year of life, according to preliminary findings from the Immune Development in Early Life (IDEaL) Rome Cohort. Findings from the cohort will be presented during the Pediatric Academic Societies (PAS) 2026 Meeting, taking place April 24-27 in Boston.
Environmental exposures during infancy may influence immune development and respiratory health. While the harms of tobacco smoke are well established, the broader effects of ambient air pollution on susceptibility to respiratory infections remain poorly defined. The IDEaL Rome cohort (Ospedale Pediatrico Bambino Gesù (OPBG); Rome, Italy), part of a National Institutes of Health (NIH)/National Institute of Allergy and Infectious Diseases (NIAID)-supported longitudinal study led by the Precision Vaccines Program at Boston Children’s Hospital, investigates early-life risk factors and immunologic pathways contributing to infection vulnerability, asthma development and vaccine responsiveness. Airborne pollutants are increasingly recognized as potential disruptors of immune maturation during critical developmental windows, yet high-quality population data in infants remains limited.
“Our findings from the IDEaL Rome cohort suggest that the air infants breathe in their first year of life does more than just affect their lungs,” said Donato Amodio, MD, PhD, Assistant Professor at OPBG and lead author of the study.
It may fundamentally shape their immune resilience. We found a clear, significant link between common urban pollutants and a higher burden of respiratory infections and wheezing. This research underscores the urgent need for environmental protections to safeguard our children during their most critical developmental windows.”
Donato Amodio, Ospedale Pediatrico Bambino Gesù
Infants enrolled in the IDEaL Rome cohort underwent clinical assessments at 2, 5, 9 and 12 months, with additional structured follow-ups via phone interviews. Physician-diagnosed respiratory infections and wheezing episodes were recorded in a dedicated eCRF. Residential postal codes were linked to the closest government air quality monitoring station to estimate exposure to particulate matter (PM₁₀), nitrogen oxides (NOₓ), and nitrogen dioxide (NO₂). Cumulative pollutant exposure was computed up to each visit. Pairwise Spearman correlations were evaluated between exposure metrics and infection outcomes.
Higher cumulative exposure to air pollutants was associated with an increased number of respiratory infections in the first year of life. Significant positive correlations were observed for PM₁₀ (r=0.47, p< 0.001), NOₓ (r=0.39, p< 0.001), and NO₂ (r=0.39, p< 0.001) with total recurrent respiratory infections (RRI). Similar associations were found with wheezing episodes (PM₁₀ r=0.25; NOₓ r=0.24; NO₂ r=0.23; all p< 0.001). Individual infections, including bronchiolitis, bronchitis, acute otitis media, SARS-CoV-2 infection, and tonsillitis, also demonstrated significant but more modest effects (average r~0.20) (Fig. 1).
The findings support an association and potential role for ambient air pollution in increasing respiratory infection burden in early childhood. Integration of high-resolution environmental monitoring data will refine exposure estimates and help clarify mechanisms linking pollutants to impaired infant immune defenses. This work raises the possibility that early environmental health protections may reduce infection vulnerability in infancy.
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