Related Experiment Videos
Prevention of Haemophilus influenzae type b disease
1Center for American Indian and Alaskan Native Health, Johns Hopkins University, Baltimore, MD 21205.
Insights
New Haemophilus influenzae type b (Hib) conjugate vaccines, HbOC and Hib-OMPC, are now licensed for infants 2 months and older. These vaccines offer protection against Hib meningitis, significantly reducing childhood illness and death.
Area of Science:
- Pediatrics
- Immunology
- Vaccinology
Background:
- Haemophilus influenzae type b (Hib) is a primary cause of meningitis in young children, particularly infants under two years old.
- The traditional Hib polysaccharide vaccine (Hib-PRP) showed limited efficacy in infants younger than 18 months.
- Bacterial polysaccharide immune globulin (BPIg) demonstrated preventative capabilities but is not licensed for routine use.
Purpose of the Study:
- To review the development and efficacy of new Haemophilus influenzae type b (Hib) conjugate vaccines.
- To assess the protective potential of novel Hib vaccines in infants and young children.
- To evaluate the impact of licensed Hib conjugate vaccines on disease reduction.
Main Methods:
- Review of clinical trials involving four different Hib conjugate vaccines in the USA.
- Evaluation of vaccines linking Hib polysaccharide to carrier proteins (e.g., HbOC, Hib-OMPC).
- Analysis of vaccine efficacy data in infants aged 2 months and older.
Main Results:
- Two Hib conjugate vaccines, HbOC and Hib-OMPC, demonstrated protection in infants from 2 months of age.
- HbOC (Hib capsular oligosaccharide linked to CRM197) and Hib-OMPC (Hib capsular polysaccharide linked to Neisseria meningitidis outer membrane protein complex) are now licensed in the USA.
- These vaccines are expected to significantly decrease Hib disease morbidity and mortality.
Conclusions:
- Licensed Hib conjugate vaccines provide effective protection for infants as young as two months.
- Widespread adoption of HbOC and Hib-OMPC vaccines is anticipated to substantially reduce the burden of Hib disease.
- Advances in vaccinology have led to improved strategies for preventing serious childhood infections like Hib meningitis.
Abstract:
Haemophilus influenzae type b (Hib) is the leading cause of meningitis in children < 5 years of age. The majority of cases of Hib occur in infants < 2 years of age. Until recently the only vaccine available against this disease contained the pure polysaccharide (PRP) of Hib (Hib-PRP vaccine). The Hib-PRP vaccine was demonstrated to be efficacious in infants > 18 months of age but not below that age. This product was licensed for routine use in the USA for children aged 24 months or more. Recently a hyperimmune globulin termed bacterial polysaccharide immune globulin (BPIg) was prepared by immunizing adult donors with Hib-PRP, meningococcal and pneumococcal vaccines. BPIg has been demonstrated to prevent Hib infections when it is administered to infants at 4-month intervals. However, BPIg has not been licensed for routine use in the USA. A number of new Hib conjugate vaccines have also been developed in the last few years by convalently linking the Hib-PRP to different carrier proteins. Four different Hib conjugate vaccines have undergone clinical trials in the USA. Two of these vaccines, HbOC (Hib capsular oligosaccharide linked to CRM197) and Hib-OMPC (Hib capsular polysaccharide linked to Neisseria meningitidis outer membrane protein complex) have been demonstrated to protect infants aged 2 months or more from Hib disease. Both HbOC and Hib-OMPC are currently licensed for routine use in the USA. The widespread use of these vaccines should have a substantial impact in reducing morbidity and mortality from Hib disease.