Flu Clinical Trials

⁃ Index Participants (Participants With Influenza Virus Infection):

• First participant in a household with influenza virus infection in the current influenza season

• Fewer than 6 HHCs

• Agreement by all household members to participate in the study and comply with the study protocol for the duration of the study

• Diagnosed as having influenza with positive rapid influenza diagnostic test (RIDT) or polymerase chain reaction (PCR) result

• Onset of symptoms within 48 hours or less at time of signing Informed Consent Form (ICF)/Assent Form

• PCR (-) or antigen test (-) for severe acute respiratory virus-coronavirus 2 (SARS-CoV-2) using point-of-care or local laboratory test

⁃ HHCs of Index Participants:

• Lived with the index participant for 48 hours or more prior to informed consent/assent

• Meet all the following criteria and are judged not to have influenza virus infection by the investigator: body temperature (tympanic) \<37.5 degrees Celsius (°C); no influenza-like symptoms (cough, sore throat, headache, nasal discharge/nasal congestion, feverishness or chills, muscle or joint pain, or fatigue) at screening; negative RIDT or PCR result for influenza

• For participants 12 years of age or older, ability to evaluate influenza symptoms by using a participant influenza symptoms diary; For participants under 12 years of age, capability of parents/caregivers to evaluate influenza symptoms by using a participant influenza symptoms diary

• PCR (-) or antigen test (-) for SARS-CoV-2 using point-of-care or local laboratory test