Influenza Vaccine in Pediatric Recipients of Hematopoietic-Cell Transplants
Jennifer E. Schuster, Lubna Hamdan, Daniel E. Dulek, Carrie L. Kitko, Einas Batarseh, Zaid Haddadin, Laura S Stewart, Anna Stahl, Molly Potter, Herdi Rahman, Spyros A. Kalams, Susan Coffin, Monica I. Ardura, Rachel L Wattier, Gabriela Marón, Claire Bocchini, Elizabeth A. Moulton, Michael Grimley, Grant Paulsen, Christopher J. Harrison, Jason L. Freedman, Paul A. Carpenter, Janet A. Englund, Flor M. Muñoz, Lara Danziger‐Isakov, Andrew J. Spieker, Natasha Halasa
Abstract
To the Editor: Pediatric recipients of hematopoietic-cell transplants (HCT) are at high risk for influenza-related illness and death. They also have weaker humoral immune responses to influenza vaccination than healthy children, which suggests that alternative vaccine regimens are needed. 1 Previous phase 1 studies showed that high-dose influenza vaccines are immunogenic in some high-risk populations without evident safety concerns, but data are lacking for pediatric recipients of HCT. 2-4 We conducted a phase 2, multicenter, doubleblind, randomized, controlled trial (Pediatric HCT Flu Study; ClinicalTrials.gov number, NCT02860039) that compared immunogenicity and safety between high-dose trivalent influenza vaccine (HD-TIV) and standard-dose quadrivalent influenza vaccine (SD-QIV) in children and adolescents 3 to 17 years of age who had received an allogeneic HCT 3 to 35 months earlier. The trial was conducted over three influenza seasons (2016 through 2019). The protocol (available with the full text of this letter at NEJM.org) was approved by the institutional review board at each site, and writ-