Pilot Influenza Challenge Study

This is a research study to understand what happens when a person is infected with influenza ("flu") and how the body controls the infection. Healthy participants (challenge) will be infected with a strain of flu (H3N2), and followed to see what symptoms occur and when they occur. Blood will be drawn and nasopharyngeal (NP) swabs will be collected before participants are infected to understand if having antibodies can protect participants from flu infection or lead to a milder flu illness. Blood will also be drawn and NP swabs collected after participants are infected to understand how and when the body's immune response to flu occurs. Participants will also breathe through a device for virus collection every other day. Participants will be screened during one or more visits and will stay in the inpatient challenge unit for at least 10 days, maybe longer. Participants will complete a FLU PRO Diary Card daily. Blood will be drawn before the challenge and on Days 2, 4, and 8 while in the inpatient unit. NP samples will be taken every day to check for viruses and on certain days, immune responses such as antibodies. If on Day 8 (7 days after the challenge) the participant still has flu virus, medicine will be offered to treat the flu and the participant will be asked to stay in the challenge unit until NP swabs are negative for 2 consecutive days. Once the participant is discharged from the challenge unit, they will be asked to return to the clinic for 3 more visits. At the end of the study will be a final phone call.