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A live human parainfluenza type 3 virus vaccine is attenuated and immunogenic in young infants

Ruth A Karron, Robert B Belshe, Peter F Wright

    The Pediatric Infectious Disease Journal
    |June 7, 2003
    PubMed

    Insights

    A new intranasal parainfluenza type 3 virus (PIV-3) vaccine, cp-45, shows promise for preventing respiratory illness. This live attenuated vaccine is safe and immunogenic in infants as young as one month old.

    Area of Science:

    • Virology
    • Vaccinology
    • Pediatric Infectious Diseases

    Background:

    • Parainfluenza type 3 virus (PIV-3) is a significant cause of pediatric lower respiratory tract infections globally.
    • Currently, no licensed PIV-3 vaccine is available to prevent these infections.

    Purpose of the Study:

    • To evaluate the safety, infectivity, immunogenicity, and phenotypic stability of a live attenuated cold-adapted (ca) and temperature-sensitive (ts) PIV-3 vaccine (cp-45).
    • To assess the vaccine's efficacy in various age groups, including adults, seronegative children, and infants as young as one month old.

    Main Methods:

    • Sequential open-label and placebo-controlled, double-blind studies were conducted in 20 adults, 24 PIV-3-seropositive children, 52 PIV-3-seronegative infants and children, and 49 infants (1-2 months old).
    • Intranasal administration of a single dose of cp-45 vaccine was used in adults and seropositive children, while seronegative children received higher doses.
    • Infants received two doses of vaccine at 1- or 3-month intervals. Safety, infectivity, immunogenicity, and phenotypic stability were assessed.

    Main Results:

    • The cp-45 vaccine was well-tolerated across all age groups.
    • Vaccine infection rates were high (94%) in seronegative children and infants.
    • Antibody responses were detected, with IgA to hemagglutinin-neuraminidase being a key indicator in young infants. Temperature-sensitive intermediate (tsi) viruses were transient and not clinically significant. Cold-adapted revertants were not detected.

    Conclusions:

    • The cp-45 vaccine is appropriately attenuated and demonstrates immunogenicity in infants as young as one month.
    • The findings support further development of the cp-45 vaccine for PIV-3 prevention.
    Abstract

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