Study of the Infectivity, Safety and Immunogenicity of Two Recombinant, Live-Attenuated, B/HPIV3 Vectored Vaccines Expressing the Fusion Glycoprotein of HMPV Delivered by Nasal Spray to HPIV3-Seropositive Children 24 to <60 Months of Age
HPIV3 and HMPV are viruses that can cause breathing problems in children. The goal of this clinical trial is to look at the safety of 2 experimental HPIV3/HMPV vaccines in HPIV3-seropositive children ≥ 24 months to \< 60 months of age. Children will receive B/HPIV3/HMPV-PreF-A vaccine, B/HPIV3/HMPV-F-B365 vaccine, or placebo, and participants will not know which study product they have received.
The main goals of the study are to find out whether these vaccines are well-tolerated and infectious in HPIV3-seropositive children.
The general procedures include daily temperature measurements and daily contact with the participant for the first 28 days, giving a single dose of one of the 2 study vaccines or placebo delivered by nasal sprayer, about 9 in-person visits, a physical examination, 7 clinical assessments, 2 blood samples, 9 nasal swabs and monthly contacts with the participant between Days 29-180.
Additional visits may occur if the child has a respiratory illness, fever, or ear infections. The illness visit will include a nasal swab and a clinical assessment.
Gender: All
Ages: 24 Months - 59 Months
Human Metapneumovirus
Human Parainfluenza Virus Type 3