This is an observational and descriptive study that will provide preliminary comparative information about the safety and immunogenicity of Fluzone® vaccine among children aged 6 to 12 weeks (the investigational group, also referred to as the 2-month-old group) versus children aged 24 to 36 weeks (the control group, also referred to as the 6-month-old group). The study is not designed to achieve any preset statistical power, and no hypotheses will be tested.