Increased respiratory syncytial virus-associated hospitalizations and ambulatory visits in very preterm infants in the first year of life following discontinuation of access to palivizumab

Yolanda Evong; Jiaxin Luo; Lingyun Ye; John Fahey; Janis Breeze; Rebecca Attenborough; Kenny Wong; Joanne Marie Langley

doi:10.1055/a-2512-9453

Increased respiratory syncytial virus-associated hospitalizations and ambulatory visits in very preterm infants in the first year of life following discontinuation of access to palivizumab

Am J Perinatol. 2025 Jan 9. doi: 10.1055/a-2512-9453. Online ahead of print.

Authors

Yolanda Evong¹, Jiaxin Luo², Lingyun Ye², John Fahey³, Janis Breeze⁴, Rebecca Attenborough³, Kenny Wong¹, Joanne Marie Langley¹

Affiliations

¹ Pediatrics, Dalhousie University, Halifax, Canada.
² Canadian Center for Vaccinology, Dalhousie University, Halifax, Canada.
³ Reproductive Care Program of Nova Scotia, Halifax, Canada.
⁴ Pediatrics, Canadian Center for Vaccinology, Dalhousie University, Halifax, Canada.

PMID: 39788540
DOI: 10.1055/a-2512-9453

Abstract

Background: From 2002 to 2023, palivizumab was the only intervention to reduce RSV-associated hospitalizations in high-risk infants in Canada, but advances in RSV prevention are drastically changing this landscape. Eligibility criteria for this monoclonal antibody for preterm infants varied over time across each of 10 Canadian provinces and 3 territories. The national professional pediatric association (Canadian Paediatric Society) revised its eligibility recommendations in 2015, removing access for preterm infants 30 to 32 weeks gestation (WG). The province of Nova Scotia (NS) followed these recommendations the next season.

Objectives: To determine if the removal of access to palivizumab in these previously infants was associated with a change in hospital admissions, deaths or ambulatory visits associated with RSV.

Methods: We identified a retrospective cohort of NS infants born between 30 and 32 WG, without other risk factors for RSV-H, from April 2012 to September 2019 by linking 6 population-based provincial databases, and followed each infant through the first year of life. Episodes of RSV-associated hospitalization, ambulatory visits or death were identified by International Statistical Classification of Diseases and Related Health Disorders (ICD) RSV- associated diagnostic codes.

Results: Of 4835 infants born during the study period, 250 were 30-32 WG were eligible for the cohort. RSV-H increased about 10-fold following restricted access to palivizumab (0/123, to 9.4%; (95% CI 5.0, 15.9, risk difference 9.4), but no RSV-associated deaths occurred. RSV-A also increased from 5.7% to 17.3% (risk difference 11.6).

Conclusions: Discontinuation of access to a prophylactic anti-RSV monoclonal antibody in very preterm infants was associated with a higher risk of RSV-H and RSV-A. Evaluation of healthcare policy change on patient well-being is essential to assess impact and guide future decision making at the population level.