Immunogenicity of Fluzone High Dose in Immunocompromised Children and Young Adults

Inclusion Criteria: * Age ≥ 5 years and ≤ 35 years * Receiving influenza vaccination in Children's Hospital Colorado (CHC) clinic as part of routine clinical care * Only supposed to receive one dose of influenza vaccine * Rheumatology patients: must be on some type of immunosuppressive or immunomodulatory medication at the time of immunization and considered at least moderately immunosuppressed in the opinion of the primary rheumatologist. Basic guidelines for rheumatology patients: (1) Any patient receiving monoclonal antibody therapy (i.e., infliximab, etanercept, tocilizumab, anakinra) must also be taking another immunosuppressive/immunomodulatory medication; (2) Patients taking steroids as monotherapy must be on a dose of ≥ 2mg/kg/day OR ≥ 20mg/day; (3) Patients on combination therapy where the dose of a single drug may not be very high, but the combination is considered moderately or severely immunosuppressive will be eligible. * Bone Marrow Transplant patients: all patients in clinic eligible * Oncology patients: must be on some type of chemotherapy * Hemodialysis patients: must be on dialysis * Child Health Immunodeficiency Program (CHIP) patients: must have a known diagnosis of HIV * Solid Organ Transplant patients: post-transplant, influenza vaccine recommended by primary transplant physician Exclusion Criteria: * Rheumatology patients: if receiving any of the monoclonal antibodies, etanercept, infliximab, adalimumab, tocilizumab, atlizumab, or anakinra, must also be taking at least one other immunosuppressive/immunomodulatory medication * Unable to come for scheduled follow-up appointments * History of anaphylaxis reaction to influenza vaccination in the past * Severe allergic reaction to any component of the vaccine, including egg protein, or after previous dose of any influenza vaccine * History of Guillain-Barre syndrome ever in the past in the subject or in a parent or a sibling of the subject * Allergy to latex * Intravenous immuneglobulin (IVIG) within in 4 weeks preceding any blood draw * Receiving an investigational agent as part of another study or other medical treatment (investigational = not-FDA approved for any indication) * Subject not enrolled in other studies that prohibit him/her from enrolling in this study * Blood draw contraindicated * Pregnancy * Breastfeeding * Received a polysaccharide vaccine (pneumovax) w/in 3 weeks of the vaccination * Absolute neutrophil count (ANC) \< 500/uL at the time of vaccination or could potentially have ANC 500/uL during the 5 days after vaccination * Platelet count \< 50,000/uL at the time of vaccination * If a subject has a temperature ≥ 100.4°F at the time of enrollment, then the subject must choose to not enroll or delay immunization until afebrile. * Receiving influenza vaccination past December 15 of influenza season.