A live human parainfluenza type 3 virus vaccine is attenuated and immunogenic in healthy infants and children.
The safety, infectivity, immunogenicity, and phenotypic stability of the cold-passaged (cp) candidate vaccine cp-45, a cold-adapted (ca), temperature-sensitive (ts) mutant of the JS strain of human parainfluenza virus type 3 (HPIV-3), was evaluated in 114 children 6 months to 10 years old in a randomized, placebo-controlled, double-blind trial. The cp-45 vaccine was well tolerated when given intranasally to parainfluenza virus type 3 (PIV-3)-seropositive and -seronegative children. With 10(4) or 10(5) TCID50 of cp-45 vaccine, 86% of seronegative vaccines were infected, 83% of whom shed virus at a mean peak titer of 10(22) pfu/mL. Virus present in respiratory specimens retained the ts phenotype, and each of 86 PIV-3 isolates tested retained both the ca and ts phenotypes. One dose of 10(5) TCID50 of vaccine induced a serum hemagglutination-inhibiting antibody response in 81% of vaccinees; the geometric mean titer was 1:32. These studies indicate that the cp-45 HPIV-3 vaccine is satisfactorily attenuated, infectious, immunogenic, and phenotypically stable and merits further evaluation in infants and young children.
Karron
R A
RA
Department of International Health, School of Hygiene and Public Health, Johns Hopkins University, Baltimore, MD 21205, USA.
Wright
P F
PF
Newman
F K
FK
Makhene
M
M
Thompson
J
J
Samorodin
R
R
Wilson
M H
MH
Anderson
E L
EL
Clements
M L
ML
Murphy
B R
BR
D000914:Antibodies, Viral / Q000097:blood; D002648:Child; D002675:Child, Preschool; D004311:Double-Blind Method; D006385:Hemagglutination Inhibition Tests; D006801:Humans; D007223:Infant; D010224:Parainfluenza Virus 3, Human / Q000276:immunology*; D014611:Vaccination; D014613:Vaccines, Attenuated / Q000276:immunology; D014765:Viral Vaccines / Q000276:immunology*
D000914:Antibodies, Viral; D014613:Vaccines, Attenuated; D014765:Viral Vaccines