Safety and Immunogenicity of RSVpreF Coadministered With SIIV in Adults ≥65 Years of Age

The purpose of this study is to assess the safety and immunogenicity of RSVpreF when coadministered with SIIV compared to sequential administration of the vaccines when given 1 month apart (SIIV followed by RSVpreF). Additionally, the study will contribute data supporting the development of RSVpreF as a prophylactic vaccine against RSV disease in infants through maternal immunization and in older adults through active vaccination.

This Phase 3, multicenter, parallel-group, placebo-controlled, randomized, double-blind study will be conducted in Australia and/or another southern hemisphere country.

Healthy adults ≥65 years of age will be randomized 1:1 to either the coadministration group (RSVpreF + SIIV)/placebo or the sequential-administration group (placebo + SIIV)/RSVpreF. This study design intends to use a single lot of NIP SIIV that is specifically indicated for use in adults ≥65 years of age.

There are 3 scheduled study visits each 1 month apart. To assess immunogenicity, 30 mL blood will be collected prior to vaccination at Visit 1 and Visit 2, and at Visit 3.

Local reactions (redness, swelling, and pain at the injection site) occurring at the RSVpreF or placebo injection site (left deltoid) and systemic events (fever, headache, fatigue, nausea, vomiting, diarrhea, muscle pain, and joint pain) occurring within 7 days after each vaccination visit (Visit 1 and Visit 2) will be prompted for and collected daily by the participant in an e-diary device or smartphone app. SIIV injection site reactions will not be routinely collected in the e-diary.

AEs and SAEs will be collected from the signing of informed consent through Visit 3.

Eligibility Criteria:
Inclusion Criteria:

1. Male and female participants ≥65 years of age at the time of consent.
2. Participants who are willing and able to comply with scheduled visits, laboratory tests, lifestyle considerations, and other study procedures, including daily completion of the e diary for 7 days after each study vaccination.
3. Healthy participants who are determined by medical history, physical examination and clinical judgment of the investigator to be eligible for inclusion in the study.
4. Capable of giving signed informed consent

Exclusion Criteria:

1. Bleeding diathesis or condition associated with prolonged bleeding time that may contraindicate IM injection.
2. History of severe adverse reaction associated with a vaccine and/or severe allergic reaction (eg, anaphylaxis) to any component of the study intervention or any related vaccine.
3. Allergy to egg proteins (egg or egg products) or chicken proteins.
4. History of Guillain-Barré syndrome.
5. Serious chronic disorder, including metastatic malignancy, end-stage renal disease with or without dialysis, clinically unstable cardiac disease, or any other disorder that, in the investigator's opinion, excludes the participant from participating in the study.
6. Immunocompromised individuals with known or suspected immunodeficiency, as determined by history and/or laboratory/physical examination.
7. Other medical or psychiatric condition, including recent (within the past year) or active suicidal ideation/behavior, or laboratory abnormality that may increase the risk of study participation or, in the investigator's judgment, make the participant inappropriate for the study.
8. Previous vaccination with any licensed or investigational RSV vaccine at any time prior to enrollment, or planned receipt throughout the study of nonstudy RSV vaccine.
9. Previous vaccination with any influenza vaccine within 6 months before study intervention administration, or planned receipt of any nonstudy licensed or investigational influenza vaccine during study participation.
10. Receipt of any blood/plasma products or immunoglobulin, from 60 days before study intervention administration, or planned receipt throughout the study.
11. Individuals who receive chronic treatment with immunosuppressive therapy, including cytotoxic agents, monoclonal antibodies, systemic corticosteroids, or radiotherapy, eg, for cancer or an autoimmune disease, from 60 days before study intervention administration or planned receipt throughout the study. If systemic corticosteroids (\<20 mg/day of prednisone or equivalent) have been administered short term (\<14 days) for treatment of an acute illness, participants should not be enrolled in the study until corticosteroid therapy has been discontinued for at least 28 days before study intervention administration. Inhaled/nebulized, intra articular, intrabursal, or topical (skin or eyes) corticosteroid use is permitted.
12. Current alcohol abuse or illicit drug use.
13. Current use of any prohibited concomitant medication(s) or those unwilling/unable to use a permitted concomitant medication(s)
14. Participation in other studies involving investigational product(s) within 28 days prior to consent and/or during study participation
15. Investigator site staff or Pfizer employees directly involved in the conduct of the study, site staff otherwise supervised by the investigator, and their respective family members