Flu Clinical Trials

∙ The main inclusion criteria include but are not limited to the following:

∙ Primary Stratum A (non-immunocompromised participants who have chronic stable medical conditions) and Primary Stratum B (participants who are immunocompromised either due to underlying disease or receipt of immunosuppressive medications)

• Has negative rapid antigen tests for influenza and severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) prior to dosing at Day 1

• Weight is ≥ 40 kg

∙ Primary Stratum A only

• Has a history of pulmonary disease

• Has moderate to severe asthma, as defined by the Global Initiative for Asthma (GINA 2025)

• Has existing cardiac disease

• Has insulin-dependent diabetes

• Has moderate renal impairment

• Is ≥ 65 years of age at the time of randomization but does not meet any of the above criteria for Primary Stratum A, and is otherwise healthy

∙ Primary Stratum B only

• Has a solid tumor diagnosis AND has received chemotherapy and/or immunotherapy within 1 year of screening

• Has a diagnosis of a hematologic malignancy within 5 years of screening AND has received any chemotherapy or biologic therapy within 1 year of screening

• Participants who have had a solid organ transplant (SOT) must satisfy all of the following:

‣ Has received a kidney, liver, heart, or lung transplant more than 6 months prior to screening

⁃ Is currently receiving at least two immunosuppressive medications

• Participants who have had a hematopoietic stem cell transplant (HSCT) must satisfy at least one of the following:

‣ Has a history of hematopoietic stem cell transplantation (HSCT) (i.e., autologous, allogeneic, bone marrow, peripheral blood stem cell, tandem \[peripheral blood and marrow\]) within 1 year of screening

⁃ Has a history of non-autologous HSCT with graft-versus-host disease (GvHD) requiring active treatment with immunosuppressants (e.g., systemic corticosteroids ≥1 mg/kg at screening), regardless of the duration of time since HSCT

• Is receiving immunosuppressive medicines

• Has received chimeric antigen receptor-modified T-cell therapy

• Has received B-cell depleting therapies (e.g., rituximab, ocrelizumab, ofatumumab, alemtuzumab) within the 12 months prior to screening

• Has a diagnosis of any primary immunodeficiency except immunoglobulin A (IgA) deficiency

• Has advanced or untreated human immunodeficiency virus (HIV) infection