Efficacy of Palivizumab Immunoprophylaxis for Reducing Severe RSV Outcomes in Children with Immunodeficiencies: A Systematic Review

Background Palivizumab is recommended for prevention of severe respiratory syncytial virus (RSV) disease in immunocompromised children, despite a lack of strong supporting evidence. The recent approval of substitute RSV-neutralizing monoclonal antibodies against RSV, offers an opportunity to synthesize the most current evidence supporting the palivizumab standard of care.Objective To evaluate the efficacy of palivizumab in preventing acute respiratory tract infection- or RSV-related hospitalization, or mortality in immunocompromised children.Methods We searched Ovid MEDLINE and EMBASE for published clinical studies that investigated outcomes of palivizumab use in children. We included clinical trials, cohort studies, and case-control studies. The primary outcomes were RSV-related or respiratory viral infection-related hospitalizations, or RSV-related mortality. This systematic review was registered in PROSPERO (ID CRD42021248619) and is reported in accordance with the PRISMA guidelines.Results From the 1993 records, six studies were eligible and included, for a total of 625 immunocompromised children with an heterogeneous composition of primary and acquired immunodeficiencies enrolled from palivizumab programs. There were no intervention studies. None of the studies included a control group. RSV hospitalizations were infrequent (0%-3.1% of children). Most children included received palivizumab, although one study (n = 56) did not specify how many received palivizumab. RSV mortality was neither observed, in three studies, nor reported, in three other studies.Conclusions The evidence supporting the use of palivizumab for prevention of severe RSV disease in immunocompromised children remains extremely limited and appears insufficient to justify prioritizing this intervention as the current standard of care over alternative interventions. The approval of new long-acting monoclonal antibody interventions for respiratory syncytial virus prevention offers an opportunity to review the evidence supporting the current standard of care. This systematic review examined the evidence supporting the use of palivizumab in immunocompromised children.