Restricted Palivizumab Recommendations and the Impact on RSV Hospitalizations among Infants Born at > 29 Weeks of Gestational Age: An Italian Multicenter Study

Abstract

Objective: Premature infants have the highest risk of being hospitalized with respiratory syncytial virus (RSV) infections. Palivizumab is the only licensed agent for RSVhospitalization (RSVH) prophylaxis in infants born at < 35 weeks of gestational age (wGA). In 2016, the Italian Drug Agency (Agenzia Italiana del Farmaco [AIFA]) has restricted the eligibility for reimbursement to infants at high risk of RSVH, ruling out palivizumab administration for infants born at > 29 wGA. The aim of the present study was to compare the incidence of RSVH in two consecutive epidemic seasons (2015-2016 vs. 2016-2017), that is, before and after the new AIFA recommendations on palivizumab eligibility. Study Design; This was a noninterventional retrospective cohort study conducted at three neonatal intensive care units (NICUs) in northern Italy. Infants born at 29 and 35 wGA between March 15, 2015 and March 14, 2017 were enrolled for this study. Electronic medical charts were reviewed and parents were interviewed by telephone. Data were collected on neonatal course during NICU stay, palivizumab administration, and hospitalizations related to respiratory infections during the 1st year of life, comparing the infants born in season 1 with season 2. Results: Of 632 eligible infants, data were available for 536 (262 in season 1 and 274 in season 2). Overall, RSVH occurred 1.9 and 5.1% in infants in seasons 1 and 2, respectively (odds ratio [OR] = 2.77; 95% confidence interval [CI]: 0.98-7.8, p = 0.045). When the analysis was limited to patients not exposed to palivizumab, RSVHs were recorded for 1.8 and 5.9% infants in seasons 1 and 2, respectively (OR = 3.42; 95% CI: 0.96-12.20, p = 0.045). It is noteworthy that the incidence of hospital admissions for respiratory viruses other than RSV did not differ between the two seasons. Conclusion: Restricting eligibility for palivizumab reimbursement led to a significant increase in RSVH but had no impact on hospitalizations for other respiratory viruses. Future decisions on palivizumab prescription and coverage rules should be driven by a careful assessment of the cost-benefit ratio.