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

From 2002 to 2023, palivizumab was the only intervention to reduce respiratory syncytial virus (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 Pediatric Society) revised its eligibility recommendations in 2015, removing access for preterm infants 30 to 32 weeks gestation (WG). The province of Nova Scotia followed these recommendations the next season. This study aimed to determine if the removal of access to palivizumab in these previously eligible infants was associated with a change in hospital admissions, deaths, or ambulatory visits associated with RSV.We identified a retrospective cohort of Nova Scotia infants born between 30 and 32 WG, without other risk factors for RSV-H, from April 2012 to September 2019 by linking six population-based provincial databases, and followed each infant through the first year of life. Episodes of RSV-associated hospitalization (RSV-H), ambulatory visits (RSV-A), or death were identified by the International Statistical Classification of Diseases and Related Health Disorders (ICD) RSV-associated diagnostic codes.Of 4,835 infants born during the study period, 250 were 30 to 32 WG and eligible for the cohort. RSV-H increased approximately 10-fold following restricted access to palivizumab (from no RSV-H (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).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 health care policy change on patient well-being is essential to assess the impact and guide future decision-making at the population level. · Discontinuation of access to a prophylactic anti-RSV monoclonal antibody in very preterm infants 30 to 32 WG was associated with a higher risk of RSV-H and RSV-A. Evaluation of changes to health care policy on patient well-being is essential to assess impact and guide future decision-making at the population level.. · Removing access to palivizumab led to higher RSV admissions in 30 to 32 WG infants.. · The effect of health care policy changes on child well-being should be assessed routinely.. · No deaths associated with RSV were identified prior to or after the policy change..