Needle-free Jet Injection of Reduced-dose, Intradermal, Influenza Vaccine in >= 6 to < 24-month-old Children

This is a sequential phase I and II, controlled, double-blinded study to determine whether immune responses suggesting protection against influenza can safely be induced in young children by two reduced doses one month apart of 0.1 mL of a trivalent inactivated influenza vaccine (INF) administered by the intradermal (ID) route with an investigational ID spacer on a United States (U.S.)-licensed needle-free jet injector (JI), compared to two standard intramuscular (IM) 0.25 mL doses by needle-syringe (N-S) in this age group. The locale is a developing country where financial restraints for the use of full-dose influenza vaccine would limit protection from an influenza pandemic threat, where N-Ss pose dangers and drawbacks in clinical use, and where Mantoux-type N-S ID injections are difficult to administer during mass campaigns.