The influenza virus is a significant cause of morbidity in adult solid organ transplant (SOT) recipients. However, these individuals show a suboptimal response to vaccines including the 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 compared HD-IIV vs. SD-IIV in adult SOT and noted HD-IIV was safe and reported higher immunogenicity; however, the median post-transplant period was 38 months. In another phase II trial of adult SOT recipients, two doses of SD-IIV a month apart compared to one-dose SD-IIV revealed increased immunogenicity, with a median post-transplantation period of 18 months. Therefore, these studies lack evaluation in the early post-transplantation period in this vulnerable population when influenza disease is most severe. The administration of two-doses of HD-IIV in the same influenza season has also not been studied in SOT recipients. Moreover, the vast majority of SOT influenza vaccinations studies have not substantively evaluated prolonged immunogenicity. Thus, the optimal immunization strategy for SOT recipients less than 12 months post-transplant is poorly-defined. In addition, the immunologic predictors and correlates of influenza vaccine immunogenicity in SOT recipients have not been defined. The investigators hypothesize that adult solid organ transplant recipients that are 1-11 months out from transplant and are receiving high-dose inactivated influenza vaccine will have higher hemagglutination inhibition (HAI) geometric mean titers to influenza A antigens compared to adult SOT recipients receiving standard-dose inactivated influenza vaccine. To test this hypothesis and address the above critical knowledge gaps, The investigators propose to conduct a phase II multicenter randomized controlled trial comparing either two doses HD-IIV, two doses of SD-IIV, or one-dose of HD-IIV in adult kidney, heart, and liver SOT recipients 1-11 months post-transplantation. The results of this study will address significant gaps in knowledge regarding influenza vaccine strategies and immune responses in adult SOT recipients and will guide vaccine recommendations in this vulnerable population.
Age range
18 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
Geometric Mean Titers of influenza vaccine antibodies.
Timeframe: Day 56 (post-vaccination)
The number of participants reporting solicited injection site reactions and systemic reactions.
Timeframe: Within 7 days post-vaccination