The Impact of Imprinting and Repeated Influenza Vaccination on Adaptive Immunity, Transcriptomics, and Metabolomics

Seasonal influenza outbreaks continue to cause substantial disease burden, with an estimated 3-5 million cases of severe illness, and 250,000 to 500,000 deaths worldwide each year. In the United States, the Centers for Disease Control and Prevention (CDC) reports that influenza has resulted in 9.2-35.6 million illnesses with 12,000-56,000 deaths annually since 2010. There is an urgent need to better understand the immunologic responses to current licensed vaccines in order to develop a more effective vaccine that does not rely on annual updates, provides broad protection, and is durable; i.e., a universal influenza vaccine. The immune response to the influenza vaccine is affected by many parameters, including prior imprinting to a specific influenza strain based on birth cohort, as well as prior influenza vaccination. The FDA-approved, quadrivalent seasonal influenza vaccine that will be administered contains four distinct strains, two influenza A viruses (IAVs) and two influenza B viruses (IBVs). The approved seasonal influenza vaccine will be given for each season of influenza: 2018-2019, 2019-2020, and 2020-2021. This study is a prospective pilot study conducted over the course of three years (with three specific influenza seasons studied). For each year (2018-2019, 2019-2020, and 2020-2021), two cohorts of 10 participants each, who are in good health and meet all eligibility criteria, will be recruited. The influenza A virus subtype H3N2 cohort (N=30 total, 10 per year) will consist of participants born between 1968-1977, and the influenza A virus subtype H1N1 cohort (N=30 total, 10 per year) will consist of participants born between 1948-1957. Each participant will make a total of six visits to the Hope Clinic. Day 1 will include the informed consent process, and screening to ensure the subject meets all inclusion criteria and meets no exclusion criteria. For the consenting and eligible subject, the visit will also include pre-vaccination phlebotomy for baseline immunogenicity laboratory assays. After baseline sample collection, the participants will receive the FDA-approved seasonal influenza vaccine. Subsequent study visits up to 180 days post-vaccination will include collection for immunogenicity assays. This study is not powered to test a formal null hypothesis. Rather, it is a hypothesis-generating investigation that will hopefully lead to larger trials based on the findings. The study will be conducted over the course of three years to increase the total sample population size and to validate the findings over different influenza seasons.