# Comparison of High vs. Standard Dose Influenza Vaccine in Pediatric Solid Organ Transplant Recipients

> **NIH NIH U01** · VANDERBILT UNIVERSITY MEDICAL CENTER · 2024 · $1,669,617

## Abstract

PROJECT SUMMARY
Influenza virus is a significant pathogen in pediatric solid organ transplant (SOT) recipients. However, these
individuals respond poorly to standard-dose (SD) inactivated influenza vaccine (IIV). Recent studies have
investigated two strategies to overcome poor immune responses in SOT recipients: (1) administration of high-
dose (HD)-IIV compared to SD-IIV and (2) two doses of SD-IIV compared to one dose of SD-IIV in the same
influenza season. One study compared HD-IIV vs. SD-IIV in adult SOT recipients and noted that HD-IIV was
safe and more immunogenic; however, the median post-transplant period was 38 months. A phase I pediatric
study comparing a single dose of HD-IIV vs. SD-IIV was safe with higher immunogenicity, but the study was
limited by small sample size and median post-transplant vaccine administration was 26 months. In another
phase II trial of adult SOT recipients, two doses of SD-IIV one month apart compared to one-dose of SD-IIV
revealed modestly increased immunogenicity when given at a median of 18 months post-transplant. Therefore,
these studies lack both evaluation in the early post-transplant period and substantive pediatric populations.
Additionally, the administration of two-doses of HD-IIV in the same influenza season has not been evaluated in
pediatric SOT recipients. Thus, the optimal immunization strategy for pediatric SOT recipients less than 24
months post-transplant is unknown. In addition, immunologic predictors and correlates of influenza vaccine
immunogenicity in pediatric SOT recipients have not been well-defined. The central hypothesis of our
proposal is that pediatric SOT recipients 1-23 months post-transplant who receive two doses of HD-
quadrivalent inactivated influenza vaccine (QIV) will have similar safety but higher HAI geometric mean
titers (GMTs) to influenza antigens compared to pediatric SOT recipients receiving two doses of SD-
QIV. To test this hypothesis and address the critical knowledge gaps outlined above, we propose to conduct a
phase II, multi-center, randomized-controlled immunogenicity and safety trial comparing two doses of HD-QIV
to two doses of SD-QIV in pediatric kidney, heart, and/or liver SOT recipients 1-23 months post-transplant. The
results of this study will address significant knowledge gaps regarding influenza vaccine strategies and
immune responses in pediatric SOT recipients and will guide vaccine recommendations in the early post-
transplant period.

## Key facts

- **NIH application ID:** 10863881
- **Project number:** 5U01AI167799-02
- **Recipient organization:** VANDERBILT UNIVERSITY MEDICAL CENTER
- **Principal Investigator:** Lara A DANZIGER-ISAKOV
- **Activity code:** U01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $1,669,617
- **Award type:** 5
- **Project period:** 2023-06-09 → 2028-03-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10863881

## Citation

> US National Institutes of Health, RePORTER application 10863881, Comparison of High vs. Standard Dose Influenza Vaccine in Pediatric Solid Organ Transplant Recipients (5U01AI167799-02). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10863881. Licensed CC0.

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