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

Abstract

Objective

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.

Study Design

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.

Results

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).

Conclusion

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.

Key Points

• 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.

Keywords

infant - premature - antibodies - monoclonal - respiratory syncytial virus - health policy

• References

• 1 Hall CB, Weinberg GA, Iwane MK. et al. The burden of respiratory syncytial virus infection in young children. N Engl J Med 2009; 360 (06) 588-598
• 2 Li Y, Wang X, Blau DM. et al; Respiratory Virus Global Epidemiology Network, RESCEU investigators. Global, regional, and national disease burden estimates of acute lower respiratory infections due to respiratory syncytial virus in children younger than 5 years in 2019: a systematic analysis. Lancet 2022; 399 (10340): 2047-2064
• 3 Government of Canada. Statement on the prevention of respiratory syncytial virus (RSV) disease in infants. 2024 . Vol. 67
• 4 American Academy of Pediatrics Committee on Infectious Diseases, American Academy of Pediatrics Bronchiolitis Guidelines Committee. Updated guidance for palivizumab prophylaxis among infants and young children at increased risk of hospitalization for respiratory syncytial virus infection. Pediatrics 2014; 134 (02) 415-420
• 5 American Academy of Pediatrics Committee on Infectious Diseases, American Academy of Pediatrics Bronchiolitis Guidelines Committee. Updated guidance for palivizumab prophylaxis among infants and young children at increased risk of hospitalization for respiratory syncytial virus infection. Pediatrics 2014; 134 (02) e620-e638
• 6 Fergie J, Goldstein M, Krilov LR, Wade SW, Kong AM, Brannman L. Update on respiratory syncytial virus hospitalizations among U.S. preterm and term infants before and after the 2014 American Academy of Pediatrics policy on immunoprophylaxis: 2011-2017. Hum Vaccin Immunother 2021; 17 (05) 1536-1545
• 7 Fergie J, Suh M, Jiang X, Fryzek JP, Gonzales T. Respiratory syncytial virus and all-cause bronchiolitis hospitalizations among preterm infants using the Pediatric Health Information System (PHIS). J Infect Dis 2022; 225 (07) 1197-1204
• 8 Kong AM, Winer IH, Zimmerman NM. et al. Increasing rates of RSV hospitalization among preterm infants: a decade of data. Am J Perinatol 2023; 40 (14) 1529-1536
• 9 Moore D, Sinilaite A, Killikelly A. Summary of the National Advisory Committee on Immunization (NACI) statement update on the recommended use of palivizumab to reduce complications of respiratory syncytial virus infection in infants. Can Commun Dis Rep 2022; 48 (7-8): 363-366