CT18 Infant Influenza Priming Study in Vaccine Naive Infants

This study evaluates whether priming influenza naive infants, age six to 23 months, with a MF59-adjuvanted (oil in water emulsion) influenza vaccine is preferred to priming with an inactivated unadjuvanted influenza vaccine. All participants will receive a priming vaccine, either MF59-adjuvanted trivalent influenza vaccine (aTIV) or unadjuvanted quadrivalent influenza vaccine (QIV). For the booster shot the following year, two thirds of participants will receive QIV and one third will receive MF59-adjuvanted vaccine.