Conjugate vaccines for preventing Haemophilus influenzae type B infections

University of Cape Town, ICH Building, Red Cross Childlren's Hospital, School of Child and Adolescent Health, Klipfontein Road, Rondebosch, Cape Town, South Africa 7700.
Cochrane database of systematic reviews (Online) (Impact Factor: 6.03). 02/2007; 18(2):CD001729. DOI: 10.1002/14651858.CD001729.pub2
Source: PubMed


Haemophilus influenzae (H. influenzae) type b (Hib) usually affects children under the age of five. It can cause life-threatening meningitis (inflammation of the membrane around the brain) or pneumonia (serious lung infection). Hib vaccine has been introduced in high income countries, but the cost of the vaccine has prevented it being introduced into routine childhood immunisation schedules in low income countries. The review found that a large number of children have now been involved in trials of the Hib vaccine. The vaccine can reduce Hib disease and no serious adverse effects have been reported in the trials.

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    • "Shift in the infectious disease etiology from gram positive to gram negative organisms is not well-recognized by health care providers who often under utilize novel rapid diagnostic methods and/or irrationally use antibiotics leading to increased burden of ARI. Although a few studies have claimed efficacy and impact of vaccines (Hemophilus influenza (Hib), pneumococcal vaccines) in reducing the respiratory infections,[1234] ignorance and other competing priorities are major hurdles against implementing the newer vaccines in control of ARI. Within these circumstances, this review is focused toward the sensitization on disease burden, etiology, and state of newer vaccines against ARI in India. "
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    ABSTRACT: Acute respiratory infections (ARIs) are the leading cause of death among children less than 5 years in India. Emergence of newer pathogenic organisms, reemergence of disease previously controlled, wide spread antibiotic resistance, and suboptimal immunization coverage even after many innovative efforts are major factors responsible for high incidence of ARI. Drastic reduction in the burden of ARI by low-cost interventions such as hand washing, breast feeding, availability of rapid and feasible array of diagnostics, and introduction of pentavalent vaccine under National Immunization Schedule which are ongoing are necessary for reduction of ARI.
    03/2014; 5(1):15-20. DOI:10.4103/0976-9668.127275
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    • "Thus, at this stage, production and characterization of antigenic components for a S. aureus vaccine is still based on empirical approaches. Therefore, we chose to incorporate into our candidate vaccine the three known major surface polysaccharides, PNAG, CP5 and CP8, as representative of antigens that have been used successfully in other bacterial vaccines [53], [54], and three proteins, non-toxic Hla, IsdB and ClfB, due to support from other studies of protective efficacy in animal settings [5], [16], [21]. In addition, PNAG was tested because of the range of bacterial pathogens that produce this antigen, making it an attractive vaccine candidate due to its potential to protect against multiple, important human pathogens [11], [12], [55], [56], [57], [58], [59]. "
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    ABSTRACT: Staphylococcus aureus is a major cause of nosocomial and community-acquired infections for which a vaccine is greatly desired. Antigens found on the S. aureus outer surface include the capsular polysaccharides (CP) of serotype 5 (CP5) or 8 (CP8) and/or a second antigen, a β-(1→6)-polymer of N-acetyl-D-glucosamine (PNAG). Antibodies specific for either CP or PNAG antigens have excellent in vitro opsonic killing activity (OPKA), but when mixed together have potent interference in OPKA and murine protection. To ascertain if this interference could be abrogated by using a synthetic non-acetylated oligosaccharide fragment of PNAG, 9GlcNH(2), in place of chemically partially deacetylated PNAG, three conjugate vaccines consisting of 9GlcNH(2) conjugated to a non-toxic mutant of alpha-hemolysin (Hla H35L), CP5 conjugated to clumping factor B (ClfB), or CP8 conjugated to iron-surface determinant B (IsdB) were used separately to immunize rabbits. Opsonic antibodies mediating killing of multiple S. aureus strains were elicited for all three vaccines and showed carbohydrate antigen-specific reductions in the tissue bacterial burdens in animal models of S. aureus skin abscesses, pneumonia, and nasal colonization. Carrier-protein specific immunity was also shown to be effective in reducing bacterial levels in infected lungs and in nasal colonization. However, use of synthetic 9GlcNH(2) to induce antibody to PNAG did not overcome the interference in OPKA engendered when these were combined with antibody to either CP5 or CP8. Whereas each individual vaccine showed efficacy, combining antisera to CP antigens and PNAG still abrogated individual OPKA activities, indicating difficulty in achieving a multi-valent vaccine targeting both the CP and PNAG antigens.
    PLoS ONE 10/2012; 7(10):e46648. DOI:10.1371/journal.pone.0046648 · 3.23 Impact Factor
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    • "HibCV has been confirmed to be effective for healthy children [2, 16, 17]. Our research shows that HibCV is immunogenic in asplenic children and young adults; however, the measured immune response is only modest. "
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    ABSTRACT: Absence of the spleen constitutes a risk of infection caused by encapsulated bacteria. The aim of our study was to determine the immune response to Haemophilus influenzae type-b (Hib) conjugate vaccine (HibCV) in asplenic individuals, considering the cause of asplenia, the age when splenectomy was carried out, and previous Hib vaccinations. Twenty asplenic patients, aged five to 25 years, were immunized with a single dose of HibCV. The specific antibody concentrations against HibCV were measured by enzyme-linked immunosorbent assay. Before vaccinations, the geometric mean antibody concentration (GMC) had an average value of 3.21 μg/ml and was comparable for all of the patients, regardless of the causes of asplenia. After vaccinations, the GMC was significantly higher, with an average of 6.78 μg/ml. Further, 4.5 years after vaccinations, the GMC was comparable to that of previously unvaccinated children. Moreover, 17/20 patients had GMC ≥ 1.0 μg/ml, which included all of the children with congenital asplenia, children splenectomized before the age of six years, and only 57% of children splenectomized after that age. HibCV gives asplenic patients long-term protection. Hence, HibCV should be administered regardless of previous vaccinations and time from splenectomy, even if antibody evaluation is not available.
    European Journal of Clinical Microbiology 08/2011; 31(5):805-9. DOI:10.1007/s10096-011-1378-8 · 2.67 Impact Factor
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