Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0348321 (Haemophilus)
 15,372 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The incidence of acute epiglottitis in children is declining in the province of Quebec, Canada. In 1988, a PRP-D anti-Haemophilus type B vaccine was introduced into the routine vaccination schedule of 18-month-old children. A substantial reduction in the occurrence of acute epiglottitis was perceived by clinicians. Since 1992, improved new vaccines (PRP-T, HbOC, PRP-OMPC), given to 2-month-old infants, have been expected to increase the efficacy of the immunization program. The impact of the immunization program on preventing acute epiglottitis was verified using a provincial database system called Med-Echo. In the presumably vaccinated target population (0 to 6 years old), 15 children suffered acute epiglottitis in 1993, whereas 97 cases were reported on the average for each yearly period from 1984 to 1987, just before the program's inception. Thus, the incidence of acute epiglottitis in preschoolers was reduced to 15.4% of its former level. The overall efficacy of the immunization program in preventing acute epiglottitis, therefore, is estimated to be 84.6%.
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PMID:Acute epiglottitis in children: results of a large-scale anti-Haemophilus type B immunization program. 760 78

The concentration of serum antibody to the Haemophilus influenzae type b polysaccharide sufficient to confer protection against Hib disease has been estimated to range from 0.15 to 1.0 microgram/ml as measured by conventional antigen binding assays. However, the ability of these serologic tests to predict vaccine equivalence and/or protective efficacy is limited since there are important qualitative differences in vaccine-induced anti-PRP antibody, such as isotype, variable region usage, and antibody avidity. These differences may profoundly affect the biologic activity of the antibody. Also, Hib conjugate vaccination primes infants for memory antibody responses to a subsequent encounter with PRP, and immunologic priming can occur in infants with very low serum anti-PRP antibody responses to conjugate vaccination, or in those whose antibody concentrations have declined after vaccination. Primed infants are likely to be protected against Hib disease in the absence of "protective" serum antibody concentrations because priming permits a rapid serum anti-PRP antibody response upon encountering the organism. Thus, quantitative assessment of immunogenicity, by itself, is insufficient to predict vaccine equivalence or protective efficacy. In defining surrogate serologic tests for prediction of vaccine efficacy, assessments of antibody avidity and induction of immunologic memory should be included. Ideally, these assessments should be supplemented with antibody functional assays such as complement-mediated bactericidal activity, opsonic activity, or passive protection in animal models of disease.
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PMID:Laboratory correlates of protection against Haemophilus influenzae type b disease. Importance of assessment of antibody avidity and immunologic memory. 762 64

Luminol-enhanced chemiluminescence (CL) of heterologous neutrophils was used to assess the capacity of a 1-ng/ml concentration of Haemophilus influenzae type b (Hib)-specific antibodies to induce opsonization of Hib with autologous heat-inactivated sera from children immunized with Hib capsular polysaccharide-polyribosylribitolphosphate (Hib-PRP) conjugate vaccine. Serum samples from 15 of 36 children (42%) vaccinated with Hib-PRP conjugate vaccine had protective levels of Hib-specific antibodies of > or = 1,000 ng/ml. Ten of these 15 (67%) had poor or nonfunctional opsonic activity. Of the 10 children whose sera lacked opsonic activity, 5 (50%) presented with recurrent Hib infection. In contrast, none of the sera of 20 healthy adults lacked opsonic capability. CL intensity was proportional to the concentration of anti-Hib antibodies used for opsonization. Furthermore, the titers of Hib-PRP-specific antibody in children and adults did not correlate with opsonic activity. These results suggest that luminol-enhanced CL as described here with minute concentrations of antibody for opsonization can be used to assess functional capacity of anti-Hib antibodies after vaccination or natural infection in the evaluation of patients with recurrent infections.
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PMID:A rapid and sensitive chemiluminescence assay for evaluation of functional opsonic activity of Haemophilus influenzae type b-specific antibodies. 766 73

A booster dose of Haemophilus influenzae type b conjugate vaccine in the second year of life is the final step in the recommended series of doses to protect infants from invasive infection. This study assessed the safety and immunogenicity of PRP-T conjugate vaccine booster doses (Act-HIB, Connaught Laboratories Ltd). The participants were 367 healthy children who had taken part in a study of primary immunization with PRP-T. At 18-19 months old, subjects were randomly assigned to receive diphtheria-pertussis-tetanus (DPT) and PRP-T vaccines either mixed in one syringe (n = 183) or separately in opposite limbs (n = 184). Adverse events were monitored for 48 h after immunization. Blood was obtained prior to vaccination in half of the subjects (combined injections group) and following vaccination in all subjects to test for antibodies to each of the antigens administered. Local adverse reactions were infrequent with PRP-T alone and equally frequent at sites of DPT or DPT/PRP-T injection, except for redness > or = 25 mm in diameter which was more frequent after the combined vaccines (25.1 versus 14.1%, p < 0.01). Systemic adverse events did not differ in type or frequency between groups. Before immunization, the geometric mean anti-PRP level in those tested was 0.41 micrograms ml-1; 26.7% had levels below 0.15 micrograms ml-1. Both treatment groups responded strongly to vaccination. In those serially tested, anti-PRP levels rose by over 90-fold, to 38.1 micrograms ml-1.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Evaluation of booster doses of Haemophilus influenzae type b-tetanus toxoid conjugate vaccine in 18-month-old children. 776 65

Conjugate vaccines against Haemophilus influenzae type b (Hib) may modify Hib pharyngeal colonization. Hib colonization was compared in 371 infants and their families. In Oxfordshire, infants received PRP-T (polyribosylribitol phosphate conjugated to tetanus toxoid) and in Buckinghamshire they did not (controls). Infants were followed at 6, 9, and 12 months of age. Also, 6 unvaccinated Hib carriers were vaccinated and followed for 6 weeks. Hib acquisition was lower in vaccinees than controls (P < .01). During surveillance, 1.5% of vaccinees and 6.3% of controls carried Hib (P = .04). Among those with family Hib exposure, the carriage rates were 8.7% and 38.5% (P = .07), respectively. Hiv carriage rates were lower among vaccinees' unvaccinated siblings. Giving conjugate vaccine to a child carrying Hib did not rapidly terminate carriage. Thus, a primary means by which herd immunity to Hib is induced in a vaccinated population may be through reduction or delay in the initial acquisition of Hib.
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PMID:The impact of conjugate vaccine on carriage of Haemophilus influenzae type b. 779 87

Passive transfer of antibody to infants born to women immunized during the third trimester of pregnancy with a Haemophilus influenzae type b (Hib) vaccine (PRP polysaccharide or Hib conjugates PRP-D or HbOC) was studied in 50 mothers and infants and 47 nonimmunized mother-infant pairs. Geometric mean total PRP antibody by RIA was 1.2 micrograms/mL at delivery in unimmunized women and 21, 149, and 171 micrograms/mL in women who received PRP, PRP-D, and HbOC, respectively. Mean cord PRP antibody levels were 0.29, 3.0, 17.5, and 29.3 micrograms/mL for the corresponding groups. Postimmunization and cord PRP antibody levels were higher after maternal immunization with conjugate vaccines than with PRP vaccine (P < .01). PRP IgG1 subclass was transmitted more efficiently than IgG2 (56% vs. 35%, P < .01). The proportion of anti-PRP IgG transmitted from immunized mothers to infants correlated with time between immunization and delivery. Administration of PRP conjugate vaccines to women during pregnancy resulted in higher levels of PRP antibodies in infants than did polysaccharide or no vaccine.
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PMID:Transplacental antibody transfer following maternal immunization with polysaccharide and conjugate Haemophilus influenzae type b vaccines. 779 88

In Sukuta, Gambia, in 1989, 128 newborns were randomly allocated to receive the liquid form of the Haemophilus influenzae type b (Hib) polysaccharide-tetanus toxoid (PRP-T) vaccine at 1 and 3 months (group A), 2 and 4 months (group B), or not to receive the vaccine (group C). All these children also received the oral polio vaccine and the diphtheria-pertussis-tetanus (DPT) vaccine. In 1990, in Bakau, Gambia, 66 infants received the lyophilized form of the PRP-T vaccine at the same time as they received DPT vaccine: 2, 3, and 4 months. The investigators aimed to determine the safety and immunogenicity of PRP-T as a forerunner to the upcoming PRP-T efficacy trial in Gambia. In the 1989 study, the geometric mean titer (GMT) of anti-PRP antibody 1 month after the second dose was higher in group B than in group A (0.41 vs. 0.26 mcg/ml). In the 1990 study, the GMT of anti-PRP antibody was 0.09 mcg/ml after the first dose, 0.74 mcg/ml after the second dose, and 2.32 mcg/ml after the third dose. One month after the final dose, the lyophilized PRP-T vaccine yielded higher antibody levels than the liquid form. For example, 72% of infants in the lyophilized group had an antibody level greater than 1 mcg/ml compared with 18% for the liquid group. 93% of all infants in groups A and B had antibody levels above 0.15 mcg/ml, the level considered to provide immediate protection, compared with 53% for the liquid group. Serious side effects were not observed. The rate of adverse reactions correlated with the concurrent delivery of DPT vaccine. Advantages of the PRP-T vaccine include: it mixes well with DPT; if administered in a three-dose schedule to Gambian infants, it is safe and elicits a protective antibody response in most infants; and it also protects against Hib infection, a major cause of meningitis and pneumonia in infants and an important cause of major childhood-acquired disability in developing countries.
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PMID:The immunogenicity and safety of Haemophilus influenzae type b-tetanus toxoid conjugate vaccine in Gambian infants. 782 90

We randomly assigned 150 newborn infants to receive diphtheria and tetanus toxoids (DT) or Hib oligosaccharide conjugate (HbOC) at birth to determine whether exposure to the Haemophilus influenzae type b (Hib) conjugate vaccines' carrier proteins would enhance immune responses to subsequent administrations of HbOC or PRP-tetanus toxoid conjugate (PRP-T) at 2, 4, and 6 months of age. Their antibody responses were compared with those of 100 children immunized with HbOC or PRP-T beginning at 2 months of age. No serious adverse reactions were associated with neonatal vaccination. Administration of HbOC at birth did not lead to earlier or higher antibody levels. Newborn immunization with DT did not prime children for enhanced antibody responses. Moreover, Hib antibody levels were lower in DT-primed children than in children immunized beginning at 2 months of age. Diphtheria antibody levels, but not tetanus antibody levels, were also lower in children immunized with DT at birth. We conclude that neonatal immunization with Hib conjugate vaccines is not a means to provide earlier protection against invasive Hib disease. Newborn DT administration does not enhance subsequent antibody responses to Hib conjugate vaccines, and may lead to suppression of Hib and diphtheria antibody responses.
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PMID:Effect of neonatal immunization with diphtheria and tetanus toxoids on antibody responses to Haemophilus influenzae type b conjugate vaccines. 784 65

To evaluate the safety and immunogenicity of differing sequences of heterogeneous Haemophilus influenzae type b (Hib) conjugate vaccines, we randomly assigned 300 infants to one of six vaccination schedules. At 2, 4, and 6 months of age, subjects were given single or heterogeneous vaccines: Hib polysaccharide (PRP) conjugated to mutant diphtheria toxin (HbOC), PRP conjugated to outer-membrane protein of Neisseria meningitidis (PRP-OMP), or PRP conjugated to tetanus toxoid (PRP-T). No serious reactions were attributable to immunization with heterogeneous vaccines, and there were few significant differences in the rates of minor adverse reactions among groups. PRP-OMP was the only vaccine that induced an antibody response after the first dose, but significant booster responses were not seen after the second and third doses. Subjects given PRP-T vaccine responded well after two doses, but three doses of HbOC vaccine were needed for an equivalent antibody response. All the Hib vaccine schedules evaluated were immunogenic, and schedules initiated by PRP-OMP vaccine at 2 months of age, followed by two doses of either HbOC or PRP-T vaccine at 4 and 6 months of age, induced the highest antibody levels after each dose. Such schedules may be the best for protecting infants and children who are at greatest risk of having invasive Hib disease, such as American Indian children.
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PMID:Enhanced antibody responses in infants given different sequences of heterogeneous Haemophilus influenzae type b conjugate vaccines. 784 66

Efficacy of the Haemophilus influenzae type b (Hib) conjugate vaccine PRP-T (Pasteur-Merieux) was evaluated in a controlled community intervention study in the Oxford region, UK. PRP-T was offered to infants from May 1, 1991 in three of the region's eight districts and from July 1, 1991, in a fourth district. It was given by separate injection in addition to the standard diphtheria, tetanus, and pertussis vaccine according to an accelerated 2, 3, and 4 month schedule without a booster dose in the second year of life. By October 1, 1992, more than 90% of infants in vaccine districts had received at least one dose of PRP-T. None of the infants given three doses had developed Hib infection, whereas 11 infections occurred in the control population (vaccine efficacy 100%, 95% CI 80-100%). Intention-to-treat analysis also showed a high estimate of efficacy for the vaccine (90%, 50-99%). Follow-up of study children until November 1, 1993, has shown only 1 vaccine failure in an infant, and no invasive infections in those older than 1 year (average age 22 months). PRP-T vaccine had high protective efficacy with an accelerated immunisation schedule. Furthermore, the vaccine appears to remain protective through the second year of life without a booster dose. These findings provide encouragement for use of PRP-T in the Expanded Programme of Immunisation.
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PMID:Efficacy of Haemophilus influenzae type b conjugate vaccine PRP-T. 791 12


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