A Study to Evaluate the Efficacy of MEDI7510 in Older Adults

A Phase 2b, double-blind, randomized, and controlled study to evaluate the efficacy of
MEDI7510 in approximately 1,900 adult participants, globally, 60 years or older. Participants
will be randomized in a 1:1 ratio to receive a single intramuscular dose of each of 2 study
vaccines in contralateral arms: MEDI7510 + IIV or placebo + IIV in Season 1.

Participants who receive MEDI7510 in the Northern Hemisphere will be re-randomized and
blinded in Season 2 to receive either MEDI7510 + IIV or placebo + IIV in a 1:1 ratio.
Clinical efficacy will not be assessed in Season 2; however the safety of revaccination will
be assessed in Season 2.

Inclusion Criteria:

- Age ≥ 60 years at the time of screening.

- Medically stable such that, according to the judgment of the investigator,
hospitalization within the study period is not anticipated and the subject appears
likely to be able to remain in follow-up through the end of protocol-specified
follow-up.

- (Season 2): Subject received MEDI7510 and IIV in the Northern Hemisphere in Season 1.

Exclusion Criteria:

- History of allergy to any component of the vaccine.

- Receipt of seasonal influenza vaccine within 6 months prior to Season 1 dosing.

- History of allergy to or intolerance of IIV.

- Pregnancy or potential to become pregnant during the study. Females who (1) have had a
menstrual period within the 12 months prior to study enrollment or (2) are undergoing
any fertility treatment or who plan to undergo fertility treatments during the study
period are excluded.

- History of Guillain-Barré syndrome.

- Previous vaccination against RSV.

- History of allergy to eggs in adulthood.

- History of or current autoimmune disorder, with the exception of stable, treated
hypothyroidism caused by autoimmune thyroiditis, which is acceptable.

- Immunosuppression caused by disease, including human immunodeficiency virus infection
(assessed by history), or medications. Any receipt of oral or intravenous
glucocorticoid therapy within 30 days prior to enrollment or planned dosing within the
follow-up period would disqualify. Topical, intranasal, inhaled, or intra-articular
corticosteroids do not disqualify. Expected need for immunosuppressive medications
during the follow-up period would disqualify.

- History of cancer within preceding 5 years other than treated non-melanoma skin
cancer, locally-treated cervical cancer or in situ carcinoma of the breast.

- Receipt of any non-study vaccine within 28 days prior to study dosing or expected
receipt of non-study vaccine prior to the Day 29 visit in Season 1.

- Receipt of any investigational product (IP) in the 90 days prior to randomization or
expected receipt of IP during the period of study follow-up.

- Receipt of immunoglobulins or blood products within 4 months of study dosing (120
days) or expected receipt of immunoglobulins or blood products during the period of
study follow-up.

- Current bleeding or clotting disorder including use of anticoagulants other than drugs
with anti-platelet activity (such as nonsteroidal anti-inflammatory drugs,
clopidogrel, ticagrelor or aspirin).

- History of alcohol or drug abuse or psychiatric disorder that, in the opinion of the
investigator, would affect the subject's safety or compliance with study.

- (Season 2): Related Grade 3 or 4 adverse event (AE) including Grade 3 or 4 local
reaction to either MEDI7510 or IIV, any adverse event of special interest (AESI) for
an adjuvanted vaccine, or any related serious adverse event (SAE).