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, with the aim of enrolling up to 70 participants. This study enrolled males and non-pregnant females, 18-49 years old, inclusive. The participants were screened at enrollment with a history and physical exam and laboratory testing to ensure they were healthy enough to participate. Total enrollment was 60 participants. Qualifying participants were vaccinated with an FDA approved seasonal inactivated influenza vaccine (IIV) according to the package insert. The study enrolled a total 60 participants. The primary objective of the study was to characterize HA-specific plasmablasts and memory B cells after influenza vaccination. 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.