Effectiveness and safety of an Haemophilus influenzae type b conjugate vaccine (PRP-T) in young infants

C. M. Vadheim, D. P. Greenberg, S. Partridge, J. Jing, J. I. Ward, S. M. Marcy, J. Gates, E. Steinberg, B. Ackerson, V. Wong, W. Luciano, M. Sultan, C. Balakrishnan, J. Heywood, J. Miller, T. Cashmore, C. Preskill, M. Tan

Research output: Contribution to journalArticlepeer-review

49 Scopus citations


Objective. To study the safety, immunogenicity, and protective efficacy of the Haemophilus influenzae capsular polysaccharide tetanus conjugate vaccine (PRP-T). Design. Randomized, double-blind, controlled clinical trial. Setting. Southern California Kaiser-Permanente Health Plan. Participants. 10 317 infants 6 to 15 weeks of age, with no known immune dysfunction, exposure to hepatitis B, or contraindication to diphtheria-tetanus-pertussis (DTP) vaccination were enrolled between August 1989 and September 1990. Intervention. Infants were randomized to receive either PRP-T or a recombinant hepatitis B control vaccine (in addition to DTP) at approximately 2, 4, and 6 months of age. Outcome measures. Adverse reactions occurring during the first 72 hours and between doses (including hospitalizations and outpatient visits) were measured using parental reporting/interviews and review of records. Invasive disease caused by H influenzae was ascertained from the time of enrollment until December 31, 1990. Results. In October 1990, the study was prematurely terminated because of licensure of other H influenzae vaccines recommended for routine infant use. The rates of systemic and local reactions occurring within 72 hours of each vaccine dose were generally similar for infants given PRP-T and hepatitis B, but some reaction rates (local reactions, fever ≥ 102°F, irritability, crying) were significantly higher in the PRP-T group. In the month following receipt of vaccine, PRP-T-vaccinated infants experienced five definite seizures compared with three in the hepatitis B control group. Within 48 hours of vaccination, three seizures (two definite and one possible), which were thought to be related to vaccination, occurred in the PRP-T group, compared with none in the control group (P < .13). Overall morbidity, mortality, and hospitalization rates were similar in the two vaccine groups. Three cases of invasive disease caused by H influenzae occurred in the control group; none occurred in the PRP-T group. Conclusions. The PRP-T vaccine is safe and appears to be effective in preventing invasive disease caused by H influenzae type b.

Original languageEnglish
Pages (from-to)272-279
Number of pages8
Issue number2 I
StatePublished - 1 Jan 1993
Externally publishedYes


  • Haemophilus influenzae type b
  • vaccine efficacy
  • vaccine safety

ASJC Scopus subject areas

  • Pediatrics, Perinatology, and Child Health


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