CI

At a glance

ClinicalIndex Comparison Record
Phase 4Completed· 23 enrolled
Drug / intervention
Influenza Fluzone vaccinebiological
Likely dose
Not stated in record
Structured eligibility isn't available for this trial yet — see the full criteria in the Eligibility tab below.

Standardized by ClinicalIndex from the ClinicalTrials.gov record · verify against the source.

Search/NCT06567860
NCT06567860Phase 4Completed

Characterizing Late-season Influenza Vaccine Responses to Compare the 2023 and 2024 Vaccine Formulations

La Jolla Institute for Immunology·interventional·Posted Aug 23, 2024·Updated Feb 12, 2026

In Brief

A Phase 4 clinical trial evaluating Influenza Fluzone vaccine for Influenza A. Completed, enrolled 23 participants across 1 site.

Detailed Summary

Every 1-2 years, the seasonal influenza vaccine composition changes to include updated viruses, yet the precise effects of updating the vaccine remain understudied. Since the vaccine formulation for each season (with a season defined as starting in July and ending the following June) expires on June 30, vaccine formulations cannot be compared head-to-head. Thus, the 2023 and 2024 vaccines have only been compared by analyzing people given the former vaccine in the fall of 2023 and people given the latter vaccine in the fall of 2024, and baseline repertoires may have greatly changed over the course of that year. To that end, the investigators will vaccinate a cohort with the 2023 influenza vaccine between May-June 2024, in order to compare responses between individuals receiving the 2023 vaccine last fall, the 2023 vaccine late in the season (this cohort), and the 2024 vaccine next fall. The investigators will further assess whether the late-season 2023 vaccine primed this cohort to respond better to the standard 2024 vaccine with standard timing (vaccine administered around September-October).

Study Details

Study Typeinterventional
Allocation--
Masking--
Primary Purpose--
ConditionsInfluenza A
CountriesUnited States
Collaborators--

Timeline

Phase 4CompletedFinished
20252026
First PostedAug 23, 2024
Enrollment StartMay 21, 2024
Primary CompletionFeb 6, 2025
TodayJul 2, 2026
Enrollment to primary: 9 monthsPosted 1.9 years ago

Interventions

Influenza Fluzone vaccinebiological

Fluzone vaccine administered in both May-June and in September-October for each participant.