Protective Efficacy of Haemophilus influenzae Type b Polysaccharide Vaccine

PEDIATRICS ◽  
1990 ◽  
Vol 85 (4) ◽  
pp. 643-647
Author(s):  
Eugene D. Shapiro ◽  
Anne T. Berg
Keyword(s):  
United States ◽  
Haemophilus Influenzae ◽  
Protective Efficacy ◽  
The United States ◽  
Invasive Disease ◽  
Polysaccharide Vaccine ◽  
Haemophilus Influenzae Type ◽  
Haemophilus Influenzae Type B ◽  
Type B ◽  
Increased Risk

There has been uncertainty and controversy about the protective efficacy of Haemophilus influenzae type b polysaccharide vaccine almost since it first was licensed in the United States. This article will briefly review the available epidemiologic data about the protective efficacy of this vaccine in children with no recognized underlying illnesses. H influenzae type b polysaccharide vaccine was licensed in the United States in April 1985, based on the results of a randomized clinical trial that was conducted in Finland.1 That study indicated that the vaccine's protective efficacy was 90% against invasive disease caused by H influenzae type b in children 18 to 71 months of age. Authorities recommended that all children receive the vaccine at 2 years of age and that it be administered to children up to the age of 60 months.2,3 The Immunization Practices Advisory Committee also recommended that children at increased risk (such as those who attend group day care) receive the vaccine at 18 months and again at 24 months of age because of its inconsistent immunogenicity when administered to 18-month-old children.2 Soon after its licensure, however, reports of vaccine failures began to appear. In some instances the vaccine failure could be attributed to an identifiable immune deficiency.4,5 However, Granoff et al6 reported 54 apparently normal children who had received the H influenzae type b polysaccharide vaccine but subsequently developed invasive disease caused by H influenzae type b. The majority of these children had normal serum concentrations of total immunoglobulins, IgG2, hemolytic complement, and antibody to tetanus toxoid (a T-cell-dependent antigen).

Disease Caused by Haemophilus influenzae Type b in the Immediate Period After Homologous Immunization: Immunologic Investigation

PEDIATRICS ◽  
1990 ◽  
Vol 85 (4) ◽  
pp. 698-704
Author(s):  
Sunil K. Sood ◽  
Robert S. Daum
Keyword(s):  
United States ◽  
Haemophilus Influenzae ◽  
Capsular Polysaccharide ◽  
The United States ◽  
Invasive Disease ◽  
Haemophilus Influenzae Type ◽  
Haemophilus Influenzae Type B ◽  
Type B ◽  
Background Rate ◽  
Protein Conjugate

Several Haemophilus influenzae type b vaccines have been licensed and recommended for administration to children in the United States. These vaccines have consisted of purified polyribosylribitol-phosphate (PRP), the capsular polysaccharide of H influenzae type b,1 alone or covalently bound to one of several carrier proteins. Two of these saccharide-protein conjugate vaccines are now licensed, a polysaccharide-diphtheria toxoid conjugate (PRP-D)2 and an oligosaccharide-mutant diphtheria toxin conjugate (HbOC).3 Two others, a polysaccharide- Neisseria meningitidis outer membrane protein conjugate (PRP-OMPC)4 and a polysaccharide-tetanus toxoid conjugate (PRP-T),5 are currently in clinical trials. One concern with the use of PRP vaccine was the suggestion that the incidence of invasive disease caused by H influenzae type b in the immediate period after immunization might be increased; this idea was supported by evidence from several sources. In a case-control study of the efficacy of PRP vaccine, Black et al6 found that 4 children were hospitalized for invasive disease within 1 week of immunization, a rate of invasive disease 6.4 times greater (95% confidence interval [CI], 2.1 to 19.2) than the background rate in unvaccinated children. In Minnesota, the relative risk for invasive disease in the first week after immunization was 6.2 (95% CI, 0.6 to 45.9),7 and the results of a study conducted by the Centers for Disease Control in six areas of the United States revealed a 1.8-fold (95% CI, 0.3 to 10.2) increase in the occurrence of invasive disease caused by H influenzae type b in the first week after immunization.8 Moreover, among 16 cases of disease caused by H influenzae type b occurring within 14 days of immunization that were passively reported to the FDA,9 10 were clustered within the first 72 hours.

Safety and Efficacy of Haemophilus influenzae Type b Polysaccharide Vaccine

PEDIATRICS ◽  
1987 ◽  
Vol 80 (4) ◽  
pp. 590-592
Author(s):  
DAN M. GRANOFF ◽  
MICHAEL T. OSTERHOLM
Keyword(s):  
United States ◽  
Confidence Interval ◽  
Haemophilus Influenzae ◽  
The United States ◽  
Polysaccharide Vaccine ◽  
Haemophilus Influenzae Type ◽  
Haemophilus Influenzae Type B ◽  
Type B ◽  
Efficacy Trial ◽  
Safety And Efficacy

Haemophilus influenzae type b vaccine was licensed in the United States in the spring of 1985. Prior to licensure, extensive data had accumulated, indicating that this vaccine was safe and was immunogenic in children >18 to 23 months of age. Furthermore, in a large efficacy trial conducted in Finland, the vaccine also was found to be approximately 80% protective in preventing invasive type b Haemophilus disease in children 24 to 35 months of age (95% confidence interval 8, 95).1,2 Unfortunately, it was ineffective in children <18 months of age, the group most susceptible to Haemophilus disease, and it was of uncertain efficacy in those 18 to 23 months of age.

scholarly journals Haemophilus influenzae Type b Polysaccharide Vaccine: An Efficacy Study

PEDIATRICS ◽  
1989 ◽  
Vol 84 (2) ◽  
pp. 255-261
Author(s):  
Lee H. Harrison ◽  
Claire V. Broome ◽  
Allen W. Hightower
Keyword(s):  
Haemophilus Influenzae ◽  
Day Care ◽  
Protective Efficacy ◽  
Conditional Logistic Regression ◽  
The United States ◽  
Polysaccharide Vaccine ◽  
Haemophilus Influenzae Type ◽  
Haemophilus Influenzae Type B ◽  
Type B ◽  
Additional Information

The Haemophilus influenzae type b polysaccharide vaccine was licensed for use in the United States in April 1985. Postlicensure case-control efficacy studies have yielded markedly different estimates of efficacy, leading to contradictory recommendations to practicing physicians. To obtain additional information about the efficacy of the vaccine, we studied cases of invasive Haemophilus influenzae type b disease ascertained through active surveillance in areas with a total population of 34 million. We enrolled children 24 to 59 months of age who did not attend day-care centers. (Data from our day-care study have been published elsewhere.) For each case child, as many as three 24- to 59-month-old control children were chosen from a roster of acquaintances supplied by the child's parent. Conditional logistic regression was used, and vaccine efficacy was estimated to be 62% (95% confidence interval = 0%, 85%), which did not change significantly after adjusting for age and parental smoking, variables that were significantly different for case and control children. Results of this study support our previous finding of a positive protective efficacy, albeit lower than the efficacy of 90% found in children 18 to 71 months of age in the Finnish prelicensure trial.

Comparative Immune Responses to Haemophilus influenzae Type b Polysaccharide and a Polysaccharide-Protein Conjugate Vaccine

PEDIATRICS ◽  
1990 ◽  
Vol 85 (4) ◽  
pp. 648-650
Author(s):  
Kwang Sik Kim ◽  
Victor K. Wong ◽  
Robert Adler ◽  
Evan A. Steinberg
Keyword(s):  
United States ◽  
Los Angeles ◽  
Haemophilus Influenzae ◽  
Conjugate Vaccine ◽  
The United States ◽  
Invasive Disease ◽  
Haemophilus Influenzae Type ◽  
Haemophilus Influenzae Type B ◽  
Healthy Children ◽  
Type B

Haemophilus influenzae type b is the most common cause of bacterial meningitis in children in the United States. Antibody to the capsular polysaccharide of this organism, polyribosylribitol-phosphate (PRP), is important in protecting against invasive disease. In 1985, H influenzae type b vaccine containing only PRP was licensed in the United States for use in children 24 to 59 months of age. Studies conducted in the United States and Finland have shown that PRP vaccine is safe and immunogenic in children older than 18 months of age.1,2 In Finland, an efficacy of approximately 80% was obtained when PRP vaccine was used to prevent invasive disease caused by H influenzae type b in children older than 24 months of age.3 The immunogenicity of the PRP vaccine in children 18 to 23 months of age, however, was not clearly established. Reported rates of seroconversion after receipt of a single dose of PRP vaccine ranged from 20% to 75%1.3-5 The purpose of our studies was to evaluate the immunogenicity y of PRP vaccines and of conjugate vaccine (PRP-Neisseria meningitidis outer membrane protein complex [PRP-OMPC]) in children from the Los Angeles area. First, we conducted a randomized, prospective study to compare the immunogenicity of the PRP vaccines produced by three manufacturers. A total of 147 healthy children between the ages of 18 and 58 months were recruited from Childrens Hospital of Los Angeles and Kaiser Foundation Hospital, Los Angeles, to receive, according to a prepared randomization schedule, 25 µg of the following PRP vaccines: Hib-Immune, lot 184-669, 190-654; Hib-Vax, lot 7L91071, 7D91043; or b-CAPSA I, lot M087BD, M068BC.

Commentary: Results of Efficacy Trials in Alaska and Finland of Haemophilus influenzae Type b Conjugate Vaccine

PEDIATRICS ◽  
1990 ◽  
Vol 85 (4) ◽  
pp. 667-667
Author(s):  
Joel Ward
Keyword(s):  
Haemophilus Influenzae ◽  
Protective Efficacy ◽  
Invasive Disease ◽  
Haemophilus Influenzae Type ◽  
High Risk Population ◽  
Haemophilus Influenzae Type B ◽  
Age Group ◽  
Type B ◽  
Double Blind ◽  
Younger Age

One of the currently licensed Haemophilus influenzae type b polysaccharide conjugate vaccines currently recommended for use in children 18 months of age and older, polyribosylribitol-phosphate-diphtheria toxoid (PRP-D, Connaught Laboratories), has been evaluated in two studies for its protective efficacy in children immunized before 6 months of age.1 The peak incidence of invasive disease caused by H. influenzae type b occurs in children 6 to 18 months of age; therefore, prevention of this disease depends on the efficacy of vaccines in this younger age group. In a large, randomized, unblinded trial conducted in Finland, relatively low levels of antibody were induced after a series of three primary PRP-D immunizations at 3, 4, and 6 months of age. Despite these limited immunogenicity results, a high level of protective efficacy was shown during a 3-year period (protective efficacy of 87%, 95% confidence intervals 50% to 96%). Another trial, which was randomized, double blind, and placebo controlled, was conducted among 2113 Native Alaskan infants immunized (20 µg/0.5 mL) at 2, 4, and 6 months of age as part of their routine childhood immunizations. This population was chosen for the trial because it has the highest known incidence of invasive disease caused by H influenzae type b, and a trial in such a high-risk population could be conducted more carefully, with fewer study subjects, and in a shorter period of time. As in the Finnish trial, in this younger age group immune responses to PRP-D vaccine were meager, apparent only after the third dose of vaccine at 6 months of age.

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