Background: Influenza A H3N2 is a flu virus. Symptoms include fever, cough, and runny nose. It can also be more serious. Researchers want to know more about how influenza causes disease in people. They hope to develop new vaccines and treatments for flu infection. Objective: To find the smallest amount of Influenza A H3N2 virus that causes a mild to moderate flu infection in healthy people. Also, to study the body s immune response to this virus and how the infection develops. Eligibility: Healthy people ages 18 50 who are: Non-smokers or non-habitual smokers Willing to not smoke for at least 9 days Design: Participants will be screened under NIAID protocol #11-I-0183 Participants will stay at an isolation unit at the clinic for at least 9 days. They will remain in the isolation unit except for study-specific activities. The influenza virus will be sprayed into the nose. Participants will be monitored 24 hours a day. They will have tests, including: Medical history Physical exam Daily questionnaires about symptoms Blood and urine tests Nasal wash and swab: A small tube of salt water is placed in the nose to wash it. It then collects the fluid. Or the inside of the nose is rubbed with a swab. ECG: Measures the heart s electrical signals ECHO: Sound waves take pictures of the heart PFTs/Spirometry: They will blow into a machine that measures the air they blow. Participants will be discharged after they test negative for influenza A. Participants will return to the clinic for 4 follow-up visits over 8 weeks. They may complete questionnaires at home.
Age range
18 Years – 50 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.
Determine the minimally to moderately infective dose (MMID) of influenza A H3N2 human challenge virus, defined as the dose that induces uncomplicated mild to moderate influenza infection in at least 60% of healthy volunteers.
Timeframe: 2 yr