RSV in Young Children: Altered Seasonality and More Severe Courses After COVID-19

The Publication of the Month for March 2025 highlights important insights into the development of severe RSV infections in young children in the years following the onset of the SARS-CoV-2 pandemic. In a study published in the European Journal of Pediatrics, BREATH researchers Prof. Dr. Christine Happle, Grit Barten-Neiner, and PD Dr. Martin Wetzke, among others, present findings from the multicenter observational study PAPI (Pediatric Airway Pathogen Incident), which was launched in 2020. The study investigated how the pandemic affected the seasonality and severity of RSV infections in children under the age of two.

The data show that, following the pandemic, a higher proportion of children with RSV infections required oxygen therapy (59.4% post-pandemic vs. 54.8% pre-pandemic), and the use of non-invasive ventilation methods increased significantly (12.4% post-pandemic vs. 7.2% pre-pandemic). In addition, more children were diagnosed with hypoxemia, indicating more severe respiratory impairment. While the overall number of hospitalizations and the duration of the RSV seasons remained comparable to previous years, these findings suggest a significant shift in disease burden toward more severe courses.

The authors suggest that the altered exposure to respiratory viruses during the pandemic played a key role. Many children had little or no prior exposure to RSV by the age of two, leaving them potentially less immunologically prepared. This so-called "immunity gap" may explain the observed increase in severe cases and the higher demand for respiratory support. “Our data clearly demonstrate how profoundly RSV seasonality and disease burden were influenced by the SARS-CoV-2 pandemic,” explains Prof. Dr. Christine Happle, BREATH researcher at the Department of Pediatric Pneumology, Allergology, and Neonatology at Hannover Medical School (MHH) and senior author of the study. “Especially among the youngest children, we are seeing more frequent severe cases with oxygen deficiency, underlining the need for adapted monitoring strategies and preventive measures,” adds PD Dr. Martin Wetzke, initiator of the PAPI study.

The PAPI study, launched in 2020, is a joint project of the Department of Pediatric Pneumology, Allergology, and Neonatology at Hannover Medical School (MHH) and the CAPNETZ STIFTUNG. As a partner of the German Center for Lung Research (DZL), CAPNETZ STIFTUNG provides its nationwide research infrastructure for the study, including standardized data collection, centralized biomaterial management, and quality-assured data management. The statistical analyses are carried out by the principal investigators of the PAPI network together with the researchers from BREATH. Just a few months ago, the team demonstrated that RSV is the most common cause of severe respiratory infections in infants and young children (more information here).
 

Original publication

 

Text: BREATH

Photo: MHH/ Tom Figiel
 

Last author of the publication: Prof. Dr. Christine Happle from the Department of Pediatric Pneumology, Allergology, and Neonatology at Hannover Medical School (MHH)