THE NEED for and the present status of parainfluenza virus vaccines have been described in published reports.1 With one exception, the antigens have been administered as monovalent vaccines and antibody responses measured.1 The desired goal of respiratory virus immunization is the administration of a multivalent preparation containing the principal agents producing respiratory illness in infants and children.2 This report details the results of a vaccine trial in young infants employing three parainfluenza monovalent vaccines administered simultaneously.
Materials and Methods
Population.—An established well-baby clinic located at General Rose Memorial Hospital in Denver was chosen for the vaccine trial. All infants were born at this hospital and admitted to the Well-Baby Clinic at 6 weeks of age. Candidates for the vaccine program were healthy infants between 3 and 14 months of age, whose parents volunteered them for the study and signed a written consent for participation after full