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[Vaccines against Haemophilus influenzae B: present, past and future]
P Gómez de León-Cruces1, R Cabrera-Contreras
1Centro de Investigaciones sobre Enfermedades Infecciosas, Instituto Nacional de Salud Pública, Cuernavaca, Morelos, México.
Insights
Haemophilus influenzae type b (Hib) causes severe pediatric illnesses globally. Conjugate Hib vaccines are crucial for reducing morbidity and mortality, with new strategies and vaccine targets under investigation.
Area of Science:
- Microbiology
- Immunology
- Pediatrics
Background:
- Haemophilus influenzae type b (Hib) is a primary cause of severe pediatric diseases like meningitis, epiglottitis, and pneumonia.
- Hib infections disproportionately affect developing countries, where epidemiological data on severe diseases are often lacking.
- Despite its long history, widespread vaccine use and clinical trials have primarily occurred in developed nations.
Purpose of the Study:
- To review the impact of Haemophilus influenzae type b on global public health.
- To discuss the development and efficacy of licensed Hib vaccines, including single and conjugated preparations.
- To explore new strategies for conjugate Hib vaccines and potential vaccine targets.
Main Methods:
- Review of existing epidemiological data on Hib infections.
- Analysis of historical and current clinical trial data for Hib vaccines.
- Examination of regulatory approvals by agencies like the FDA.
- Literature review on emerging vaccine strategies and potential virulence factors.
Main Results:
- Five Hib vaccines, including one single and four conjugated formulations, have been licensed after rigorous safety and efficacy evaluations.
- Epidemiological data highlight the significant public health burden of Hib in developed countries, with a need for similar data from developing nations.
- Immunoprophylactic measures are recommended to decrease high morbidity and mortality rates associated with Hib meningitis and its sequelae.
Conclusions:
- Conjugate Hib vaccines are essential for reducing the incidence of severe pediatric diseases and their neurological complications.
- There is a need for improved epidemiological surveillance in developing countries to guide public health interventions.
- Future vaccine development may focus on novel targets such as outer membrane proteins, lipooligosaccharides, fimbriae, or pili.
Abstract:
Haemophilus influenzae type b (Hinb) is the main etiologic agent of severe pediatric illnesses, such as meningitis, epiglottitis and pneumonia. Countries most affected by this pathogen are localized in the American, European and African continents. While this organism was originally isolated 100 years ago, the first field trial using a whole killed vaccine was performed until 1959. Since then, further controlled clinical trials have mainly been conducted in the North American and European continents. Under appropriate safety and efficacy evaluation tests performed by the Federal Drug Administration Agency (FDA), five vaccines were licensed: one single and four conjugated preparations. Worldwide and regional epidemiologic data concerning serious diseases produced by this organism have shown their outstanding impact in the public health of developed countries. Unfortunately, in developing countries similar epidemiological indexes are lacking for lethal and disabling diseases, such as meningitis. In order to decrease high morbidity and mortality rates of this meningeal disease and its neurological sequelae, immunoprophylactic preventive measures have been recommended. Furthermore, some risk factors of this infant illness can also be reduced. New strategies regarding conjugate Hib-vaccines are reviewed. Finally, promising virulence factors or self Hib-structures for the production of vaccines are suggested, such as outer membrane proteins (OMP), lipooligosaccharides, fimbriae or pili.