Ambient air pollution is associated with the burden of respiratory infections in the first year of life, according to preliminary findings from the Immune Development in Early Life (IDEAL) Rome Cohort. The group’s findings will be presented during the Pediatric Academic Societies (PAS) 2026 meeting, taking place April 24-27 in Boston.
Environmental exposures during infancy can affect 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 are poorly defined. Model Rome Group (Ospedale Pediatrico Bambino Gesu (OPBG); Rome, Italy), part of a National Institutes of Health (NIH)/National Institute of Allergy and Infectious Diseases (NIAID)-supported longitudinal study. precision vaccines program At Boston Children’s Hospital, early life risk factors and immunological pathways that contribute to infection susceptibility, asthma development, and vaccine response are examined. Airborne pollutants are increasingly recognized as having potential disruption in immune maturation during critical developmental windows, yet high-quality population data in infants is limited.
“Our findings from the IDEAL Rome group show that the way infants breathe in the 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.
This may fundamentally shape their immune resilience. We found a clear, significant association between common urban pollutants and a higher burden of respiratory infections and wheezing. “This research underlines the urgent need for environmental protection to protect our children during their most critical developmental period.”
Donato Amodio, Ospedale Pediatrico Bambino Gesu
Infants enrolled in the IDEaL ROM group underwent clinical assessment at 2, 5, 9, and 12 months, including additional structured follow-up via phone interview. Physician-diagnosed respiratory infections and wheezing events were recorded in a dedicated eCRF. Residential postal codes were linked to the nearest government air quality monitoring station to estimate exposure to particulate matter (PM₁₀), nitrogen oxides (NOₓ), and nitrogen dioxide (NO₂). Cumulative pollutant exposure up to each visit was calculated. Pairwise Spearman correlations between exposure metrics and infection outcomes were evaluated.
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 (RRIs). 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) (Figure 1).
The findings support the association and potential role of ambient air pollution in increasing the burden of respiratory infections in childhood. Integration of high-resolution environmental monitoring data will refine exposure estimates and help clarify mechanisms linking pollutants to weakened infant immune defenses. This work raises the possibility that early environmental health protection may reduce susceptibility to infection in infancy.
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