Peer-reviewed article
Direct and indirect effects of COVID-19 on infant bronchiolitis: a population-wide registry study from Northern Italy
Valeria Nazzari, Albert Navarro Gallinad, Laura Ghirardi, Claudia Gianbartolomei, Anna Maria Paganoni et al. ·
Summary
Written by AI, not yet AICS's view · claude-sonnet-5-5This registry study used health records from Lombardy, Northern Italy, to look at emergency room visits for bronchiolitis in infants aged 0-6 months between 2012 and 2023. The rate of visits doubled after the COVID-19 pandemic, from about 2 to 4 or more per 100 person-time in 2021-2023. The rise was not explained by infant age at the visit, clinical severity or the shape of the epidemic peak. Infant routine vaccination and maternal COVID-19 vaccination showed little association with bronchiolitis episodes. The authors conclude that several changes together, not one factor, probably drove the increase.
Key points
- The study covered almost 1 million births in Lombardy, Italy, using administrative health data from 2012-2023.
- Incidence rates of bronchiolitis ER presentations in 0-6 month olds doubled in 2021-2023 compared with pre-pandemic levels (from 2 to ≥4/100 person-time).
- The surge was not explained by changes in infant age at ER visit, clinical severity or the shape of the epidemic peak.
- Infant routine vaccination (hazard ratio 1.09, 95%CI 0.98-1.22) and maternal COVID-19 vaccination (odds ratio 0.91, 95%CI 0.76-1.09) showed little association with bronchiolitis episodes.
- The post-pandemic increase is likely driven by multiple epidemiological changes rather than a single factor.
Limitations
Only the abstract is available, so details on data quality, how the contributing factors were measured, and the other mechanisms involved are not given. As an observational study of administrative data, it cannot show what caused the increase, and it is about one region of Italy.
Abstract
Abstract Background COVID-19 pandemic modified trends of infant bronchiolitis, leading cause of emergency room (ER) attendance in infants in high income countries, primarily due to Respiratory Syncytial Virus. Understanding recent pandemic-related epidemiological shifts could inform affordable prevention efforts to improve sustainability and coverage of prophylactic treatments beyond maternal vaccines and infant monoclonal antibodies. Methods We estimated incidence rates (IR) of bronchiolitis ER presentations in 0-6month olds in 2012-2023 in a region-wide cohort of almost 1 million births using administrative health data from Lombardy, Italy. To assess potential contributors, we investigated direct and indirect COVID-19-related factors, including disease severity, shape of the epidemic peak, parental health seeking behaviour and vaccine coverage. We estimated COVID-19 maternal vaccination associations using mothers-infants data linkages and multivariable-adjusted logistic regression. Findings Compared to pre-pandemic levels, IRs doubled in 2021-2023 (from 2 to ≥ 4/100 person-time). The surge could not be explained by changes in infant age at ER visit, clinical severity or in the shape of the epidemic peak. Adjusted models showed little support for a role of infant routine or maternal COVID-19 vaccination on bronchiolitis episodes (respectively hazard ratio 1.09, 95%CI: 0.98–1.22 and odds ratio 0.91, 95%CI: 0.76–1.09). Interpretation The post-pandemic increase in infant bronchiolitis is likely driven by multiple epidemiological changes rather than a single factor. As maternal RSV vaccination and infant RSV monoclonal antibodies are introduced and scale up, identifying these mechanisms will be critical to maximise their public health impact, inform complementary prevention strategies, and improve preparedness for future RSV epidemics.