Safety Study of a Human Metapneumovirus Challenge Virus in Healthy Adults

Human metapneumovirus (HMPV), a virus that causes respiratory illness, was first discovered in 2001, although humans have been infected with it for at least 50 years. HMPV may cause upper respiratory illness or no symptoms at all in healthy adults, but older adults, adults with asthma, and children may be at risk of more serious illness. HMPV is a leading cause of viral lower respiratory infection (LRI) in children, so finding a vaccine for this virus could substantially reduce the instances of childhood respiratory illnesses. The National Institute of Allergy and Infectious Diseases (NIAID) is developing a vaccine for HMPV for use in infants, but before starting clinical trials with potential HMPV vaccines, researchers need to study how wild HMPV affects healthy adults. This study will expose healthy adults to a dose of the HMPV virus to assess its ability to infect, cause disease, and create an immune system response. Participation in this study will last approximately 6 months. Participants will be admitted to an inpatient unit, where they will stay for 10 full days. On their second day in the unit, participants will receive a single dose of the virus, delivered via nose drops. Twice each day while participants are inpatients, they will undergo physical exams and have their vital signs recorded. Nasal washes and blood samples will be collected before participants receive the virus, and then daily nasal washes will be collected until they are discharged from the inpatient unit. Participants will be discharged from the unit on the 9th day after receiving virus if their nasal wash from Day 8 was free of virus. Follow-up visits will occur 28, 120, and 180 days after participants receive the virus. During follow-up visits nasal washes and blood samples will be collected.