Transmissibility, infectivity and immunogenicity of a live human parainfluenza type 3 virus vaccine (HPIV3cp45) among susceptible infants and toddlers.
BACKGROUND
This study examined the transmissibility between young children of an intranasally administered live attenuated human parainfluenza virus type 3 (HPIV3)-cp45 vaccine candidate.


METHODS
Eighty subjects were enrolled in playgroups among whom there was at least one infected vaccinee in close contact with a seronegative placebo recipient over 21 days without a confounding infection with wtHPIV3. Following vaccination viral cultures were obtained on nine occasions to detect shedding and transmission of HPIV3cp45. Serum antibody titers were measured before and 7 weeks after vaccination.


RESULTS
No child fulfilled the criteria for transmission of HPIV3cp45 giving a risk of transmission of 0.04 (95% CI 0.01-0.19), hence establishing that HPIV3cp45 is less infectious than wtHPIV3 and risk of transmission is not a limitation to further clinical development of this vaccine candidate.
Madhi
Shabir A
SA
University of the Witwatersrand/Medical Research Council Respiratory and Meningeal Pathogens Research Unit, South Africa. madhis@hivsa.com
Cutland
Clare
C
Zhu
Yuwei
Y
Hackell
Jill G
JG
Newman
Frances
F
Blackburn
Nigel
N
Murphy
Brian R
BR
Belshe
Robert B
RB
Karron
Ruth A
RA
Deatly
Anne M
AM
Gruber
William C
WC
Bernstein
David I
DI
Wright
Peter F
PF
D000914:Antibodies, Viral / Q000097:blood; D002675:Child, Preschool; D004311:Double-Blind Method; D004797:Enzyme-Linked Immunosorbent Assay; D006801:Humans; D007223:Infant; D010224:Parainfluenza Virus 3, Human / Q000276:immunology* / Q000472:pathogenicity; D010253:Respirovirus Infections / Q000635:transmission*; D014611:Vaccination; D014613:Vaccines, Attenuated / Q000276:immunology; D014765:Viral Vaccines / Q000276:immunology*
D000914:Antibodies, Viral; D014613:Vaccines, Attenuated; D014765:Viral Vaccines