PET-CT Scans in Healthy Volunteers After Flu Vaccination

Until recently, all recipients of influenza vaccine received a killed form of virus, typically in the same nondominant arm, each year before flu season. We hypothesize that natural infection, and some forms of vaccination, could allow vaccine induced responses to spread beyond the local lymph nodes near the vaccination site. From a practical perspective, if vaccine induced proliferation of specific immune cells in sites distant from the vaccination site lead to beneficial immune memory, it would suggest vaccination strategies that could be as simple as alternating the injected arm from year to year, or alternating inhaled vs. injected forms of vaccine. This will be a 4 armed prospective study of individuals receiving unilateral FluShield i.m. Healthy adult volunteers 21-55 will be grouped according to the following criteria: I. Documented history of prior natural infection with influenza A or B within the past 5 years (diagnostic test or high titer hemagglutinin HA Ab in absence of vaccination); II. History of FluMist vaccination within the past 2 years; III. History of TIV (Trivalent (Inactivated) Influenza Vaccine) vaccination, any number of times, but only in a single (e.g., non-dominant) arm. Within one month of screening and baseline blood draws for PBMCs (Peripheral blood mononuclear cells) and Ab (antibody) titers, individuals will receive FluShield injections. For those individuals with prior history of unilateral TIV injections, half will receive their shots in the same arm that has always been injected (Group IIIa). The other half of these individuals will receive Flushield in the opposite (dominant) arm (Group IIIb). Upon entering the study, 50cc of heparinized blood and 10 cc of serum will be drawn by antecubital venipuncture. Within 4 weeks of this blood draw, volunteers will receive a standard dose of i.m. TIV (FluShield). Four-seven days later they will have an FDG PET-CT scan performed after an 8 hour fast. Additional blood draws of 50cc heparinized blood and 10 cc serum will be obtained at 2, 4, and 6 weeks post vaccination, and at 10-12 months post vaccination. After the last blood draw, volunteers will also be asked questions pertaining to flu-like symptoms during the past 10 months.