Study to Assess the Safety, Pharmacokinetics, and Efficacy of Baloxavir Marboxil in Chinese Pediatric Participants 1 to <12 Years of Age With Influenza Symptoms

Exclusion Criteria

• •A participant having severe influenza virus infection symptoms requiring inpatient treatment
• •Received systemic corticosteroid or immunosuppressive therapy
• •Primary immunodeficiency syndrome
• •History of organ transplantation
• •Human immunodeficiency virus (HIV) infection
• •Immunization with a live/attenuated influenza vaccine in 2 weeks prior to randomization
• •Previous malignancy within the last 5 years or has an active cancer at any site
• •A participant who received any medications with anti-flu effect such as baloxavir, peramivir, oseltamivir, zanamivir, favipiravir, arbidol, amantadine or traditional Chinese anti-influenza medicines within 30 days before screening
• •Diagnosed with or suspected SARS-CoV-2 infection, or close contacts of diagnosed or suspected SARS-CoV-2 infected patients
• •Severe underlying disease or condition potentially affecting study evaluation in the opinion of the investigator/sub-investigator
• •A participant who received an investigational or unapproved drug product within 30 days or 5 x the half-life before screening, whichever is longer