Work continues on extending protection against Haemophilus influenzae to very young infants

Article Abstract:

Haemophilus influenzae type b causes severe life-threatening infections, such as meningitis and epiglottitis, in infants and very young children. Vaccination of infants as young as two months of age against Haemophilus influenzae type b is a goal that has not been achieved. If this can be achieved, it appears that infants will be protected against Hemophilus infections by the age of seven months, one month after their second immunization. Formerly, such vaccines were not considered effective before 15 months of age. One candidate vaccine, called HbOC (a bacterial capsule oligosaccharide coupled to a nontoxic diphtheria toxin protein), has been tested in several sites. It appeared to elicit an adequate response in 94 percent of the infants who received it at two, four, and six months. Other vaccines have also been tested, and protective efficacy studies now in progress will evaluate the differences in immunogenicity (ability to provoke an immune response) among the agents. One such protective efficacy study, started in Finland in 1987, involves 52,000 infants. Both the HbOC vaccine and PRP-D vaccine (polyribosylribitol coupled to diphtheria toxoid) are being tested, with one given to babies born on odd-numbered days of the month, and the other, to babies born on even-numbered days. Babies receive doses at four, six, and eight months of age. Results indicate that the HbOC vaccine was 97 percent effective among infants who received all vaccinations. A study of HbOC in the US is being conducted on 48,000 infants, who receive the agent at two, four, and six months of age. Presently, the vaccine appears 100 percent effective; no case of infection due to Haemophilus influenzae has occurred in the immunized group. Results will be evaluated when the study is completed, at the end of 1990. (Consumer Summary produced by Reliance Medical Information, Inc.)

Physiological aspects, Surveys, Bacterial vaccines, Hemophilus influenzae, Haemophilus influenzae, Vaccination of infants

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H influenzae vaccines gain favor

Article Abstract:

Two new vaccines that protect young infants against a severe form of bacterial infection caused by the Haemophilus influenzae type b organism have been tested. One vaccine made by Praxis Biologics is prepared by linking an extract of the bacterial protein capsule to a protein to increase the degree of antibody formation in the infant. This vaccine has maintained protection in more than 80 percent of subjects for at least two years. This agent, known as HbOC, has been field-tested extensively in Finland and California. The second vaccine, developed by Merck Sharp and Dohme, is similarly prepared by linking a bacterial capsule to a protein to increase its ability to evoke an immunologic reaction in the patient. This vaccine is unique in that a single injection has been shown to protect against infection in infants as young as two months. The Merck vaccine, known as PRP-OMP, has been tested among Navajo Indians, a group with a high attack rate for Haemophilus infections. A large scale double-blind study was stopped early when the results showed the clear protection afforded by the vaccine. In infants who received two doses of vaccine, there was only one case of Haemophilus infection, as opposed to the 14 cases in the control group, which was treated with a placebo. A committee reviewing these clinical research results suggest that both vaccines should be used, allowing early and extended coverage of infants. The Vaccine and Related Biological Products Advisory Committee of the Food and Drug Administration made no recommendation concerning the vaccination of children younger than two years of age. One researcher stated that until the H. influenzae vaccine is in general use, the long-term effects of the vaccination will not be clear. (Consumer Summary produced by Reliance Medical Information, Inc.)

Product development, Hib vaccines, Hemophilus meningitis, Merck & Company Inc. Merck Sharp and Dohme Research Laboratories Div., Praxis Biologics Inc.

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Clearing the Way for New Combination Vaccine Use

Article Abstract:

Researchers discussed the best ways of evaluating combination vaccines at a meeting at the National Institutes of Health (NIH). Children receive 12 shots in the first 18 months and 15 to 19 by the time they are six years old. Adding more vaccines to the schedule will make it even more complicated. For this reason, combination vaccines contain several vaccines in one shot. However, this makes it difficult to evaluate the combination vaccine.

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