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 antibody response to three Haemophilus influenzae type b vaccines was examined in 134 infants 17 to 22 months of age. Sera were collected from each subject before and 1 month after vaccination with either purified H. influenzae type b capsular polysaccharide (polyribosyl-ribitol phosphate (PRP] or one of two protein-conjugated vaccines (PRP-D or HbOC). Comparison of the two conjugate vaccines revealed that HbOC produced an antibody response greater than or equal to 1.0 micrograms/ml in 96% compared with 72% who were vaccinated with PRP-D (P less than 0.05). The isotype distribution of the antibodies produced by the two vaccines was similar. While all of the vaccines resulted in higher concentrations of anticapsular IgG1 than IgG2, the IgG1:IgG2 ratio was significantly higher in subjects immunized with HbOC. The IgG1:IgG2 ratio was similar in subjects immunized with PRP or PRP-D. The clinical significance of these observations remains to be determined.
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PMID:Prospective comparison of the immune response of infants to three Haemophilus influenzae type b vaccines. 206 19

The safety and immunogenicity of the HbOC conjugate vaccine have been evaluated in a study population of 61,080 children in the Kaiser Permanente Medical Care Program of Northern California. Half of the population served as controls. The vaccine was given as part of a three-dose regimen in the first year of life with the first dose given between 6 weeks and 6 months of age, a minimum interval of 1 month between doses and with the third dose given by 1 year of age. The vaccine was highly immunogenic with 97% of infants developing 1 microgram/ml or more of anti-polyribosyl phosphate antibody as measured by Farr assay 1 month after completion of the three-dose series and with 71% maintaining this concentration until a booster dose was given at approximately 18 months of age. There were three cases of Haemophilus influenzae type b disease after the first dose of vaccine and two of these children died. However, there was no statistically significant difference between either the incidence of H. influenzae type b disease or the mortality rate in infants after one dose of HbOC vaccine when compared with H. influenzae type b disease incidence and mortality in unvaccinated children of the same age. The rate of sudden infant death syndrome following HbOC vaccine was lower than that observed within the Kaiser Permanente Medical Care Program as a whole or in the three counties in which sudden infant death syndrome surveillance was tabulated. Immediate local and systemic reactions were evaluated by telephone interviews of 6887 infants within 72 hours of vaccine.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Safety and immunogenicity of oligosaccharide conjugate Haemophilus influenzae type b (HbOC) vaccine in infancy. The Northern California Kaiser Permanente Vaccine Study Center Pediatrics Group. 206 19

Haemophilus influenzae type b is responsible for an estimated 15,000 to 20,000 cases of meningitis per year in the United States, mainly in children 2 months to 5 years old. The mortality rate from meningitis due to H influenzae type b infections ranges from 5% to 10%. Despite antibiotic treatment, up to 35% of survivors have permanent neurologic sequelae. In addition to meningitis, H. influenzae type b is responsible for other invasive infections, including epiglottitis, septicemia, cellulitis, septic arthritis, osteomyelitis, pneumonia, pericarditis, and otitis media; approximately 30,000 cases H influenzae diseases occur annually in the United States. The diseases peak in incidence between 6 and 12 months of age, with almost one half of the cases occurring before 1 year of age. About 75% of disease caused by H influenzae type b occurs in children younger than 24 months old. The incidence of disease is higher in children of certain groups, including blacks, Hispanics, Eskimos and Native Americans, young children attending day-care facilities, patients with asplenia or antibody-deficiency syndromes, and children of lower socioeconomic status. There is considerable evidence that antibody to the capsular polysaccharide (polyribosylribitol-phosphate [PRP] of H influenzae type b is protective.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Immunogenicity of a new Haemophilus influenzae type b conjugate vaccine (meningococcal protein conjugate) (PedvaxHIB). 210 17

In 1985, the first capsular polysaccharide (polyribosylribitol-phosphate [PRP]) vaccine for Haemophilus influenzae type b was licensed and recommended for routine use in children between 24 and 60 months of age. In the United States, approximately 75% to 90% of invasive disease due to H influenzae type b occurs in infants younger than 24 months, a population for whom H influenzae type b polysaccharide vaccine is inadequately immunogenic and protective. In an effort to enhance the immunogenicity of H influenzae type b polysaccharide vaccine for children in the most susceptible age groups, conjugate vaccines have been developed in which the capsular PRP of H influenzae type b has been bound to a variety of carrier proteins, thereby conferring the vaccines with thymic-dependent attributes. One such conjugate vaccine, in which the carrier protein is diphtheria toxoid (PRP-D), was licensed in 1987 and has been recommended since 1988 for routine use in children 18 months of age and older. A second conjugate vaccine, in which an oligosaccharide derivative of H influenzae type b capsular PRP is coupled to CRM, a nontoxic mutant diphtheria toxin (oligo-CRM), was licensed in 1988 and is a sanctioned alternative to PRP-D. Another investigational conjugate vaccine, in which the polysaccharide is linked to the outer membrane protein of Neisseria meningitidis group B (PRP-OMPC), has been demonstrated to be both safe and immunogenic when administered in a two-dose schedule to 2- to 6-month-old infants. However, anti-PRP antibody levels decline significantly during the ensuing 10 to 15 months; they rise significantly in response to booster doses of either PRP or PRP-OMPC administered 10 to 15 months after the initial priming doses of PRP-OMPC.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Safety, tolerability, and immunogenicity of concurrent administration of Haemophilus influenzae type b conjugate vaccine (meningococcal protein conjugate) with either measles-mumps-rubella vaccine or diphtheria-tetanus-pertussis and oral poliovirus vaccines in 14- to 23-month-old infants. 210 19

The Haemophilus influenzae vaccine consisting of purified type b capsular polysaccharide (polyribosylribitol-phosphate [PRP]) was shown in Finland to be protective, with 90% efficacy in children older than 18 to 23 months of age. However, a wide range of estimates of vaccine efficacy has been reported in the United States after its licensure in 1985. These estimates range from -55% to +89%. In addition, the PRP vaccine was not effective in children younger than 18 months of age, in whom 70% to 80% of meningitis cases occur. A further development was the introduction of H influenzae type b polysaccharide-protein conjugate vaccines such as the PRP-D. These conjugate vaccines were found to be more immunogenic than PRP vaccine in children of all ages. Two doses of PRP-D in infants 7 months of age and older induced antibody levels equal to or greater than levels in infants 24 months of age who received the PRP vaccine alone. Recently, Eskola et al reported that repeat vaccinations with PRP-D at 3, 4, 6, and 14 months of age was 83% protective (95% confidence interval, 26% to 96%). Yet PRP-D vaccine elicits only low serum antibody levels in infants younger than 7 months of age. Because of the discrepancy in efficacy results for the PRP vaccine in the United States and Finland and the lack of data about the protective efficacy of PRP-D vaccine in infants in the United States, the PRP-D vaccine is currently recommended only for children 18 months of age or older.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Haemophilus influenzae type b conjugate vaccine (meningococcal protein conjugate): immunogenicity and safety at various doses. 210 20

Immunization with Haemophilus influenzae type b capsular polysaccharide (polyribosylribitol-phosphate [PRP]) has resulted in limited and variable antibody radioimmunoassay in infants younger than 2 years of age. Although an H influenzae type B vaccine has been in use for several years, it is not used now for the age group at greatest risk for disease. In an effort to enhance immunogenicity, PRP has been coupled to various carrier proteins and to an outer membrane protein complex (OMPC) from Neisseria meningitidis group B. The latter approach has yielded a vaccine that elicits a good antibody response after a single 15-micrograms dose of vaccine in infants as young as 2 months of age, as measured by radioimmunoassay and immune bacteriolysis. In this report we describe the results of a pilot study using this H influenzae type B conjugate vaccine, PedvaxHIB, in children from 2 months to 4 years of age. Three different vaccine lots were examined for consistency of response. Sera were measured for antibody levels by radioimmunoassay and for functional activity using an opsonophagocytic assay using human adult neutrophils. These assays correlated well and demonstrated the excellent immune response and biologic activity of sera from infants vaccinated with this unique H influenzae type B conjugate vaccine.
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PMID:Opsonophagocidal activity in sera from infants and children immunized with Haemophilus influenzae type b conjugate vaccine (meningococcal protein conjugate). 210 21

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, 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) and an oligosaccharide-mutant diphtheria toxin conjugate (HbOC). Two others, a polysaccharide-Neisseria meningitidis outer membrane protein conjugate (PRP-OMPC) and a polysaccharide-tetanus toxoid conjugate (PRP-T), 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 al 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), 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.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Disease caused by Haemophilus influenzae type b in the immediate period after homologous immunization: immunologic investigation. 210 22

The first vaccines licensed in the United States for prevention of Haemophilus influenzae type b (Hib) disease were composed of the capsular polysaccharide of Hib, polyribosylribitol phosphate (PRP). The vaccines, licensed in 1985, were moderately effective in preventing Hib disease in children aged 24-59 months. In December 1987, the first Hib conjugate vaccine was licensed. The vaccine was recommended for use in children aged 18-59 months to prevent meningitis and other forms of invasive disease caused by Hib. This report summarizes surveillance for Hib meningitis and provides data on the use of Hib vaccine in Seattle-King County, Washington, where Hib meningitis surveillance methods have remained the same since 1984.
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PMID:Decline in Haemophilus influenzae type b meningitis--Seattle-King County, Washington, 1984-1989. 212 16

The importance of Haemophilus influenzae type b as the main cause of serious bacteremic infections in young children and the consequent need for preventive measures have been widely appreciated since the 1970s. The knowledge that serum antibodies to the polysaccharide capsule of H influenzae type b increase with age and correlate with resistance to this infection encouraged work toward a vaccine based on the H influenzae type b polysaccharide. Such a vaccine was used in 1974 in a field trial in Finland. Two important lessons were learned. First, vaccine-induced antibodies to the polyribosylribitol-phosphate (PRP) polysaccharide correlated with protection from disease caused by H influenzae type b, so that the serum anti-PRP concentration predicting protection could be estimated as 1 microgram/mL. Second, the vaccine was not effective in infancy; protection and serum antibody concentrations above 1 microgram/mL were not observed before 18 to 24 months of age. The poor immunogenicity of PRP in infancy has been observed in a large number of studies and is shared by other bacterial polysaccharides. Although the reason for this is not known, the most likely hypothesis associates poor immunizing ability in infancy with the "T-independent" nature of these polysaccharide antigens. Such antigens would be unable to stimulate T lymphocytes; therefore, immunity to them would depend exclusively on B cells and antibodies produced by them. If infants, by and large, lack B cells that could be stimulated directly by a polysaccharide antigen, they cannot respond to the polysaccharide vaccine. This hypothesis immediately suggests possibilities for improvement of the vaccine.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Clinical experience with Haemophilus influenzae type b conjugate vaccines. 217 55

Haemophilus influenzae type b is a major cause of bacterial meningitis and other invasive diseases in children under four years of age. One surface antigen, the type b capsular polysaccharide, polyribosylribitol phosphate (PRP), is a primary virulence factor of the organism. Antibody directed against PRP is protective; however, the purified polysaccharide is poorly immunogenic in young children. Polysaccharide-protein conjugate vaccines have been prepared which are significantly more immunogenic and efficacious in young children compared to the plain polysaccharide vaccine. Noncapsular surface antigens may also play a role in the virulence of H. influenzae. Some mutants (or phase variants) which differ in lipooligosaccharide (LOS) structure exhibit decreased virulence in the infant rat model of bacteremia. Proteins including the IgA protease, pili, a 98K outer membrane protein (OMP) as well as OMPs P1, P2 and P6 have also been examined in considerable detail, but whether they have a role in the virulence of the organism remains to be determined. However, antibody directed against the 98K OMP as well as P1, P2 and P6 is protective in the infant rat model of bacteremia. The role of antibody directed against LOS epitopes in protection is less clear, due at least in part, to phase variation in LOS antigens. Characterization of one surface antigen of H. influenzae type b, the capsular polysaccharide, already has led to the prevention of many cases of Haemophilus disease. Characterization of the noncapsular antigens together with a more detailed understanding of the mechanisms of virulence, most likely will permit development of even better vaccines, and possibly better treatment modalities, in the future.
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PMID:Haemophilus influenzae: surface antigens and aspects of virulence. 219 7


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