Evaluation of Human Immune Responses to Influenza Virus Vaccination in Healthy Volunteers

This was an open label, single arm, Phase IV study of longitudinal immunologic responses to influenza vaccine in healthy adult participants. This study enrolled males and non-pregnant females, 18-49 years old. The primary objective of the study was to characterize hemagglutinin (HA)-specific plasmablasts and memory B cells after influenza vaccination. The secondary objective was to investigate the longevity of humoral immunity to influenza virus in humans. Total enrollment was 60 participants. This was a multi-year study. Participant duration in this study was 180 days. Participants were screened at enrollment with a history and physical exam and laboratory testing to ensure they were healthy enough to participate. Qualifying participants were vaccinated with an FDA approved seasonal inactivated influenza vaccine (IIV) according to the package insert. Approximately 450 ml of blood was collected for the research assays during the course of the study. Specifically, 16 ml was be collected for screening; 48ml was collected at enrollment; 96ml was collected at visit Days 7 and 14; and 64 ml was collected at 28, 90, and 180 days post vaccination. A total of 60 participants were enrolled over the course of the study. Participants who completed the study were given the option to re-enroll in subsequent years as long as they continued to meet all inclusion/exclusion criteria. Re-enrolling participants were re-consented, given new participants identifiers, and counted towards the enrollment number goal for each year of participation. Safety was assessed from the time of study enrollment through the last study visit, via monitoring of vital signs, and querying for change in health status. Note: Due to the Coronavirus Disease 2019 (COVID-19) pandemic, all non-essential research was halted in mid-March 2020. New enrollments were placed on hold for this study. Follow-up visits were also halted, which impacted the timing of participants' subsequent follow-up visits. Five participants had their Day 180 visits halted due to the COVID-19 pandemic. A request was submitted to the Emory University Institutional Review Board to extend the missed visit windows for the Day 180 visit for a maximum of up to 90 days, to ensure that ample time would be available to bring participants back for their missed visits. Enrollment for this study ended on September 30, 2020, before research activities could resume at Emory.