Young children with chronic conditions are more likely to be hospitalized for respiratory syncytial virus (RSV) than healthy children, according to a new study. The research will be presented at the Pediatric Academic Societies (PAS) 2025 Meeting, held April 24-28 in Honolulu.
Toddlers with chronic conditions are hospitalized for RSV at twice the rate as healthy toddlers over their first two seasons. The risk was highest for children born very prematurely under 28 weeks of gestation, or with conditions affecting multiple organs, the lungs, heart, or digestive system.
Researchers recommend that children with those specific conditions receive immunization against RSV in their first season to increase protection, even if their mother was vaccinated. Current guidelines suggest pregnant women should receive vaccination before birth to pass on antibodies.
“Our research finds that many children with chronic conditions require seasonal RSV immunization beyond the period of protection that can be achieved with maternal vaccination. It expands current definitions from traditionally defined high-risk groups to other children with chronic conditions that could equally benefit from RSV immunization, up to two years of age,” said Marina Viñeta Páramo, graduate student at the University of British Columbia Faculty of Medicine and presenting author. “Our study underscores the importance of children with chronic conditions getting immunized against RSV in their second season, and in their first season even if their mother was vaccinated.”
This study analyzed data from 431,937 infants born in British Columbia, Canada, between 2013 and 2023, including 25,452 infants with chronic health conditions.
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EDITOR:
Marina Viñeta Páramo will present “RSV Hospitalizations in Children with Chronic Medical Conditions During Their First and Second Seasons: A Retrospective Population, Season-Stratified Cohort Study” on Sun., April 27 from 4:45-5:00 PM ET.
Reporters interested in an interview with Marina should contact Amber Fraley at amber.fraley@pasmeeting.org.
The PAS Meeting connects thousands of pediatricians and other health care providers worldwide. For more information about the PAS Meeting, please visit www.pas-meeting.org.
About the Pediatric Academic Societies Meeting
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Abstract: RSV Hospitalizations in Children with Chronic Medical Conditions During Their First and Second Seasons: A Retrospective Population, Season-Stratified Cohort Study
Presenting Author: Marina Viñeta Páramo
Organization
University of British Columbia Faculty of Medicine
Topic
Public Health & Prevention
Background
Advisory immunization committees across jurisdictions recommend long-acting RSV monoclonal antibody therapy in groups of children who are at high risk of severe RSV disease in their second season, and in children who remain at high risk late in their first season even if their mother received RSV vaccination. However, these recommendations are imprecise due to a lack of data on chronic medical conditions (CMCs) associated with increased risk beyond traditional risk groups.
Objective
To determine population-level incidence rates for RSV hospitalization in groups of children with CMC in their first and second seasons.
Design/Methods
We conducted a retrospective population cohort analysis using health administrative data in all children born in British Columbia (BC), Canada (5.7 million population in 2024), enrolled in BC public health care over 10 years (2013-2023) with or without a CMC (defined using the Pediatric Complex Chronic Condition, PCCC classification). Children were followed until the day preceding their third RSV season or April 1, 2024, whichever came first. The main outcome was RSV hospitalization based on ICD-10 codes, stratified by season of RSV exposure. Subgroup analyses examined effects based on the body system affected by CMC and by specific conditions in children with CMC.
Results
The cohort included 431,937 children with a median follow-up of 728 days, of whom 25,452 (5.9%) were diagnosed with CMC within their first two years of life. A total of 4,567 (1.1%) children experienced 4,593 hospitalizations over their first and second seasons. RSV hospitalization rates in children with CMC exceeded those in healthy children for the first two seasons (Table 1). Children with CMC had significantly longer hospital and PICU stays and required more mechanical ventilation (Table 1). In the second RSV season, children with CMC had higher RSV hospitalization rates than those in the first season, especially when their conditions affected the respiratory, cardiovascular, or gastrointestinal systems, involved congenital anomalies, or affected multiple body systems, including Down syndrome (Figures 1 and 2).
Conclusion(s)
Children with CMCs remain at high risk of severe RSV outcomes in their second season. Specifically, second-season hospitalization incidence rates exceeded first-season rates overall in children with CMC affecting multiple body systems or those with Down syndrome. This population season-stratified cohort analysis provides data that can directly inform the use of long-acting monoclonal antibody therapy in high-risk groups of children for a second RSV season.
Tables and Images
Table 1
Figure 1
Figure 2
