Safety and Immunogenicity of High-Dose Quadrivalent Influenza Vaccine in Participants ≥65 Years in the US

This randomized, modified double-blind, active-controlled, multi-center trial will be
conducted in healthy adults (≥ 65 years) to assess the safety and immunogenicity (geometric
mean titers and seroconversion for the 4 virus strains at 28 days post vaccination) of the
high-dose quadrivalent influenza vaccine (QIV-HD) compared to one of the high-dose trivalent
influenza vaccines (TIV-HDs) containing either the B strain from the primary lineage
(TIV-HD1; licensed vaccine [Fluzone® High-Dose] for the 2017-2018 Northern Hemisphere [NH]
influenza season) or the B strain from the alternate lineage (TIV-HD2, investigational TIV-HD
containing an alternate B strain).

Inclusion Criteria:

- Aged ≥ 65 years on the day of inclusion

- Informed consent form has been signed and dated

- Able to attend all scheduled visits and to comply with all trial procedures

Exclusion Criteria:

- Participation at the time of trial enrollment (or in the 4 weeks preceding the trial
vaccination) or planned participation during the present trial period in another
clinical trial investigating a vaccine, drug, medical device, or medical procedure

- Receipt of any vaccine in the 4 weeks (28 days) preceding the trial vaccination or
planned receipt of any vaccine prior to Visit 2

- Previous vaccination against influenza (in the preceding 6 months) with either the
trial vaccine or another vaccine

- Receipt of immune globulins, blood or blood-derived products in the past 3 months

- Known or suspected congenital or acquired immunodeficiency; or receipt of
immunosuppressive therapy, such as anti-cancer chemotherapy or radiation therapy,
within the preceding 6 months; or long-term systemic corticosteroid therapy
(prednisone or equivalent for more than 2 consecutive weeks within the past 3 months)

- Known systemic hypersensitivity to any of the vaccine components, or history of a
life-threatening reaction to the vaccines used in the trial or to a vaccine containing
any of the same substances

- Thrombocytopenia or bleeding disorder, contraindicating IM vaccination based on
investigator's judgment

- Deprived of freedom by an administrative or court order, or in an emergency setting,
or hospitalized involuntarily

- Alcohol or substance abuse that, in the opinion of the investigator, might interfere
with the trial conduct or completion

- Chronic illness that, in the opinion of the investigator, is at a stage where it might
interfere with trial conduct or completion

- Identified as an Investigator or employee of the Investigator or trial center with
direct involvement in the proposed trial, or identified as an immediate family member
(i.e., parent, spouse, natural or adopted child) of the Investigator or employee with
direct involvement in the proposed trial

- Personal or family history of Guillain-Barré syndrome

- Neoplastic disease or any hematologic malignancy (except localized skin or prostate
cancer that is stable at the time of vaccination in the absence of therapy and
subjects who have a history of neoplastic disease and have been disease free for ≥ 5
years)

- Moderate or severe acute illness/infection (according to Investigator judgment) on the
day of vaccination or febrile illness (temperature ≥ 38.0°C [≥ 100.4°F]). A
prospective participant should not be included in the trial until the condition has
resolved or the febrile event has subsided