Comparison of Full-dose Flu Vaccine to Half-dose Flu Vaccine

This study compared full-dose Flu vaccine to half-dose Flu-vaccine during the 2004-2005 flu season.

This was a Phase II prospective, single-blind to dose, randomized study that compared the immunogenicity of subjects receiving half-dose Fluzone® compared to full-dose Fluzone®, 2004-2005 formulation. 1440 healthy subjects, ages 18-64 years old and not currently indicated for influenza vaccination under the interim ACIP guidelines, were divided into 8 strata based on age, gender, and previous exposure to influenza vaccine, and randomized to receive either half-dose (0.25mL) Fluzone® or full-dose (0.5mL) Fluzone® by intramuscular injection into the deltoid muscle.

Eligibility Criteria:
Inclusion Criteria:

* Able to understand and comply with all study procedures including availability for all study visits and follow up surveys within 6 months following study enrollment.
* DEERS eligible beneficiaries eligible for influenza vaccination and able to give informed consent.
* Age 18-49

  * Patients presenting to travel clinic with no exclusion criteria;
  * Household contacts and out-of-home caretakers of infants from 6-23 months of age;
  * Hospital and/or employees providing service to the public who are not eligible for the post-October 5th recommendations for priority immunization;
  * DOD employees eligible for influenza vaccination prior to October 5th but excluded in the post October 5th guidelines;
  * People living in dormitories or under other crowded conditions, to prevent outbreaks;
* Ages 50-64 years of age who are not eligible for the post-October 5th recommendations for priority immunization and with no standard of care contraindications to vaccination.
* Eligible in the Department of Defense for influenza vaccination

Exclusion Criteria:

* all children aged \< 18 years (includes children aged 6 months-18 years on chronic aspirin therapy);
* adults aged \>65 years;
* persons aged 2-64 years with underlying chronic medical conditions:

  * includes persons with chronic cardiac or pulmonary disease, diabetes mellitus, hemoglobinopathy, or immunosuppressive illness;
  * any acute or chronic condition that, in the opinion of the investigator, would render vaccination unsafe or interfere with the evaluation of response.
* use of experimental vaccines or medications within 30 days of study entry;
* receipt of parenteral immunoglobulin within 60 days of study entry;
* all women who will be pregnant during the influenza season;
* residents of nursing homes and long-term care facilities;
* health-care workers involved in direct patient care and included in DOD priority 1; and;
* military recruits;
* out-of-home caregivers and household contacts of children aged \<6 months.
* Anyone with clinical contraindications for receiving the inactivated influenza vaccine such as a history of severe allergic reaction to prior influenza vaccinations, severe allergy to egg and/or egg proteins and gelatin.
* DOD Priority 1: Deployed or deploying (with orders) service members and others designated as critical to national defense.
* DOD Priority 2: Medically high risk in accordance with ACIP guidelines (includes health-care workers with direct patient contact)
* Any acute or chronic condition that, in the opinion of the investigator or her provider designee would render vaccination unsafe or interfere with the evaluation of the response.