Collection of Serum Samples From Children and Older Adults Receiving the 2019-2020 Formulations of Fluzone® Quadrivalent and Fluzone® High-Dose Influenza Vaccines, Respectively

All participants received 1 intramuscular injection of the study vaccine associated with their assigned group at Visit 1. For participants 6 months to \< 9 years of age for whom 2 doses of influenza vaccine are recommended per Advisory Committee on Immunization Practices (ACIP) guidance, a second intramuscular injection of Fluzone Quadrivalent vaccine was administered at Visit 2 (28 days after Visit 1).

Blood specimens were obtained from all participants prior to the first vaccination:

* At Visit 1 (Day 0) and 28 days following the final vaccination (Visit 2, if no study vaccine was administered at Visit 2; or Visit 3, if a second dose of study vaccine was administered at Visit 2), for participants 6 months to \< 9 years of age (Group 1 and Group 2) * At Visit 1 and 21 (window, 21-28) days post-vaccination (Visit 2), for participants greater than or equal to (\>=) 65 years of age (Group 3) Serious Adverse Events (SAEs), suspected unexpected serious adverse reactions (SUSARs), or Adverse Event of Special Interests (AESIs) were collected from Visit 1 through Visit 2 for participants receiving 1 dose of study vaccine, and from Visit 1 through Visit 3 for participants receiving 2 doses of study vaccine.

Study duration per participant was approximately 28 days for participants 6 months to less than (\<) 9 years of age, and 21 days for participants \>= 65 years of age.