Protective efficacy of Haemophilus influenzae type b polysaccharide and conjugate vaccines in children 18 months of age and older

Article Abstract:

The first vaccine to protect against Haemophilus influenzae type b (Hib) disease was licensed in the United States in April 1985 and was a polyribosylribitol phosphate (PRP) polysaccharide. The vaccine was shown to provide 90 percent protection for children immunized between eighteen months and six years of age. However, results of five additional studies varied, indicating that the vaccine was between completely ineffective and 88 percent effective. Other lines of evidence suggesting that the PRP vaccine was ineffective included: frequent reports of vaccine failure; limited immunogenicity of the vaccine, or its inability to activate the immune system; and lack of a reduction in incidence of Hib disease. The Hib vaccine has since been modified to improve its immunogenicity by linking the PRP polysaccharide to a protein. The first Hib conjugate vaccine, licensed in December 1987, consisted of the PRP linked to diphtheria toxoid, and was called the PRP-D vaccine. The new PRP-D vaccine is capable of increasing the antibody response 5 to 10 times that provoked by the PRP vaccine in young children aged 15 to 30 months. The antibody response involves the production by immune B cells of immune proteins (antibodies) that are specifically directed against the Hib. The efficacy of the new PRP-D vaccine was not assessed before the vaccine was licensed. Hence, the effectiveness of PRP and PRP-D vaccines in protecting against Hib disease was assessed in 79 children aged 18 to 59 months with Hib disease and 212 subjects without the illness. There were 17 PRP vaccine failures and 2 PRP-D vaccine failures more than two weeks after immunization. These findings show that the PRP vaccine was ineffective and the PRP-D vaccine was 88 percent effective in protecting against Hib disease. (Consumer Summary produced by Reliance Medical Information, Inc.)

Evaluation, Hemophilus infections

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Safety and immunogenicity of a serogroups A/C Neisseria meningitidis oligosaccharide-protein conjugate vaccine in young children: a randomized controlled trial

Article Abstract:

A meningococcal conjugate vaccine appears to produce a greater immune response to Neisseria meningitidis than the polysaccharide vaccine. Neisseria meningitidis causes bacterial meningitis, which is a significant cause of death, especially in children in developing countries. Researchers tested a vaccine against the A and C subtypes of the bacterium that is conjugated to a protein. Ninety children between the ages of 18 and 24 months were vaccinated with two doses of the polysaccharide vaccine or one of two strengths of the conjugate vaccine. There were few serious reactions to either vaccine. Both vaccines increased antibodies to the A subtype to similar degrees, but the conjugate vaccine led to antibody levels to the C subtype that were twice as high as the polysaccharide vaccine. The conjugate vaccine also produced much higher levels of bactericidal antibodies than the polysaccharide vaccine.

Testing, Meningococcal infections

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A randomized trial of low-air-loss beds for treatment of pressure ulcers

Article Abstract:

Low-air-loss beds may speed the healing of pressure ulcers in elderly nursing home residents. The mattress on these beds consists of inflatable fabric pillows that are kept inflated by an electric fan. Of 84 nursing home residents, 43 were given a low-air-loss bed and 41 were given a convoluted foam mattress, which is the conventional treatment for pressure ulcers. The size and severity of the ulcers were similar in both groups. Healing was measured twice a week by tracing the area of the ulcer on plastic film. The ulcers of the patients using the low-air-loss bed healed three times faster than those of the patients using the conventional mattress. This was true regardless of the severity of the ulcer. Although the low-air-loss beds may be more expensive, they may dramatically reduce the healing time in hospitalized patients with pressure ulcers.

Care and treatment, Innovations, Bedsores, Decubitus ulcer, Mattresses

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