Flu Vaccine Response in Patients on Biologic Therapies

This proposed study will assess the immunogenicity, safety, and clinical efficacy of an influenza vaccine booster dose strategy in patients with autoimmune diseases who are receiving immunosuppressive therapies. Investigators will compare serologic responses to single versus a booster dose of influenza vaccine in patients with inflammatory bowel disease (IBD- Crohn's Disease or Ulcerative Colitis) or rheumatologic diseases who are receiving immunosuppressive therapies. Subjects will be randomized to receive either one or two doses of influenza vaccination in year #1. In year# 2, all participants will be given two doses of influenza vaccine. Serologic responses will be measured pre and 4-6 weeks post vaccination. This study will also assess the immunogenicity and safety of a booster vaccine strategy in the prevention of influenza-like illness (ILI). Investigators anticipate that booster dose strategy will improve both clinical and serologic responses in this vulnerable population.