Comparing Two Doses of High-Dose and Standard-Dose Influenza Vaccines in Children and Teens Who Have Received Organ Transplants

What this Trial Is About

Pediatric solid organ transplant SOT recipients face challenges with influenza virus infections, as they typically have weaker responses to the standard-dose SD inactivated influenza vaccine IIV. Previous studies in adults and small pediatric groups suggest high-dose HD IIV or two doses of SD-IIV may improve immune responses, but these have not been tested extensively in children within 24 months post-transplant. This trial aims to determine if two doses of HD quadrivalent inactivated influenza vaccine QIV are safe and generate stronger immune responses than two doses of SD-QIV in this vulnerable pediatric population. This phase II, multi-center, double-blind randomized trial will compare two doses of SD-QIV 0.5 mL 15bcg of each influenza antigen against two doses of HD-QIV 0.7 mL 60bcg of each influenza antigen given 28 to 42 days apart. Approximately 312 pediatric heart, liver, and kidney transplant recipients between 1 and 23 months post-transplant will be enrolled and randomized to one of the two vaccine groups. Active influenza surveillance will monitor symptoms and nasal swabs will be collected before and after vaccination during the influenza season. Participants will undergo safety monitoring for local and systemic reactions within 7 days after each vaccine dose and have blood drawn to measure immune response four weeks after the second dose. Additional assessments include antibody levels after each dose and durability of response 180 days post second vaccination. Weekly communication during influenza season will track illness symptoms. Participation is expected to last through the vaccination and follow-up periods to evaluate vaccine safety and immune response in these pediatric transplant recipients.

High vs.Standard Dose Influenza Vaccine in Pediatric Solid Organ Transplant (SOT) Recipients