# Comparison of High Dose vs. Standard Dose Influenza Vaccines in Lung Allograft Recipients

> **NIH NIH U01** · VANDERBILT UNIVERSITY MEDICAL CENTER · 2024 · $828,717

## Abstract

PROJECT SUMMARY
Influenza virus is a significant pathogen in solid organ transplant (SOT) recipients, including lung allograft
recipients. Moreover, compared to other SOT, lung allograft recipients have more severe influenza disease.
However, due to requisite immunosuppression, 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. The first study, conducted in adult SOT
recipients, reported that HD-IIV was safe and more immunogenic; however, the median post-transplant period
was 38 months. The second study, another phase II trial in adult SOT recipients with a median post-transplant
period of 18 months, reported that two doses of SD-IIV administered one month apart was more immunogenic
than one-dose of SD-IIV. While promising, these studies lack evaluation in the early post-transplant period,
when SOT patients are most vulnerable to influenza. Moreover, these studies had limited inclusion of lung
transplant recipients, a population that is most at risk for influenza-related comorbidities, including respiratory
failure, acute cellular rejection, and chronic lung allograft dysfunction. Finally, the administration of two doses
of HD-IIV in the same influenza season has not previously been evaluated in SOT recipients. Thus, the optimal
immunization strategy for lung allograft recipients in the early post-transplant period remains unknown. In
addition, the immunologic predictors and correlates of influenza vaccine immunogenicity in lung allograft
recipients have not been well-defined. The central hypothesis of our proposal is that lung allograft
recipients who are 1-35 months post-transplant and receiving two doses of HD-quadrivalent
inactivated influenza vaccine (QIV) will have higher HAI geometric mean titers (GMTs) to influenza
antigens compared to those 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 HD-QIV to two doses SD-QIV administered one month
apart in lung allograft recipients who are ≥16 years and 1-35 months post-transplant. This study will be
conducted at five lung transplant centers—Vanderbilt University Medical Center, Duke University,
Northwestern University, University of Alabama in Birmingham, and University of Washington. The results of
this study will illuminate immune responses in adult lung allograft recipients and help guide vaccine
recommendations during the early post-transplant period. Moreover, our findings may help guide optimal
vaccine strategies in other immunosuppressed populations.

## Key facts

- **NIH application ID:** 10770519
- **Project number:** 5U01AI167789-03
- **Recipient organization:** VANDERBILT UNIVERSITY MEDICAL CENTER
- **Principal Investigator:** NATASHA Bassam HALASA
- **Activity code:** U01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2024
- **Award amount:** $828,717
- **Award type:** 5
- **Project period:** 2022-02-18 → 2027-01-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10770519

## Citation

> US National Institutes of Health, RePORTER application 10770519, Comparison of High Dose vs. Standard Dose Influenza Vaccines in Lung Allograft Recipients (5U01AI167789-03). Retrieved via AI Analytics 2026-05-23 from https://api.ai-analytics.org/grant/nih/10770519. Licensed CC0.

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