Clinical Study to Evaluate Safety, Immunogenicity of Investigational Flu Vaccine Compared to an Approved Flu Vaccine in Children Previously Vaccinated in Trial V118_05 (NCT01964989)

A Phase III, Randomized, Observer Blind, Multicenter Study to Evaluate the Safety and Immunogenicity of Repeated Exposure to Either the Same or Alternate Type of Vaccine, Adjuvanted or Non-adjuvanted Quadrivalent Subunit Influenza Virus Vaccine (aQIV or QIV), Administered to Subjects Previously Vaccinated in Trial V118_05 (NCT01964989)

Safety, Immunogenicity of an Adjuvanted Quadrivalent Subunit Influenza Virus Vaccine Compared to Non-Adjuvanted Comparator Influenza Vaccine in Children Previously vaccinated in Trial V118_05. Subjects will receive either the Same or Alternate Type of Vaccine.

Inclusion Criteria:

In order to participate in this study, all subjects must meet ALL of the inclusion criteria described.

• Subject's parent/legal guardian has voluntarily given written informed consent after the nature of the study has been explained according to local regulatory requirements, prior to study entry.
• Male or female subject who has completed their Visit 13 (Study Day 366 for non-naïve subjects) or clinic Visit 15 (Day 390 for naïve subjects) in parent trial V118_05.
• For naïve subjects in parent trial V118_05 to have received two doses of the same study vaccine (i.e. 2 doses of aQIV or 2 doses of QIV).

Exclusion Criteria:

• Previous immunization with any influenza vaccine (licensed or investigational) within 6 months prior to enrollment.
• Subjects with a clinical condition representing a contraindication to intramuscular vaccination or blood draws.
• Unwillingness of the parent(s)/ legal guardian(s) of the subject to refuse to participate in another clinical trial while enrolled in V118-05E3.

Additional eligibility criteria may be discussed by contacting the site.