Evaluation of a live, cold-passaged, temperature-sensitive, respiratory syncytial virus vaccine candidate in infancy

J Infect Dis. 2000 Nov;182(5):1331-42. doi: 10.1086/315859. Epub 2000 Sep 22.


A live-attenuated, intranasal respiratory syncytial virus (RSV) candidate vaccine, cpts-248/404, was tested in phase 1 trials in 114 children, including 37 1-2-month-old infants-a target age for RSV vaccines. The cpts-248/404 vaccine was infectious at 104 and 105 plaque-forming units in RSV-naive children and was broadly immunogenic in children >6 months old. Serum and nasal antibody responses in 1-2 month olds were restricted to IgA, had a dominant response to RSV G protein, and had no increase in neutralizing activity. Nevertheless, there was restricted virus shedding on challenge with a second vaccine dose and preliminary evidence for protection from symptomatic disease on natural reexposure. The cpts-248/404 vaccine candidate did not cause fever or lower respiratory tract illness. In the youngest infants, however, cpts-248/404 was unacceptable because of upper respiratory tract congestion associated with peak virus recovery. A live attenuated RSV vaccine for the youngest infant will use cpts-248/404 modified by additional attenuating mutations.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antibodies, Viral / blood
  • Breast Feeding
  • Child, Preschool
  • Enzyme-Linked Immunosorbent Assay
  • Humans
  • Immunization
  • Immunoglobulin A / blood
  • Infant
  • Respiratory Syncytial Viruses / immunology*
  • Temperature
  • Vaccines, Attenuated / immunology
  • Viral Vaccines / immunology*
  • Virus Shedding


  • Antibodies, Viral
  • Immunoglobulin A
  • Vaccines, Attenuated
  • Viral Vaccines