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Designing meningitis vaccines
1Department of Paediatrics, University of Oxford, John Radcliffe Hospital, Headington. jim.buttery@paediatrics.ox.ac.uk
Insights
Conjugate vaccines improve young children's immune response to encapsulated bacteria like Haemophilus influenzae (Hib), Neisseria meningitidis (Nm), and Streptococcus pneumoniae (Sp). These vaccines have shown success in preventing invasive diseases caused by Hib and pneumococcal serotypes.
Area of Science:
- Immunology
- Vaccinology
- Pediatrics
Background:
- Young children have a limited immune response to encapsulated bacteria, such as Haemophilus influenzae (Hib), Neisseria meningitidis (Nm), and Streptococcus pneumoniae (Sp).
- These bacteria are a major cause of serious infections like septicaemia and meningitis in UK children.
- Bacterial capsular polysaccharides, crucial for virulence, are poorly immunogenic in young children.
Purpose of the Study:
- To review the development and efficacy of conjugate polysaccharide vaccines.
- To highlight their role in overcoming immunologic unresponsiveness in young children.
Main Methods:
- Review of existing literature on conjugate polysaccharide vaccines.
- Analysis of clinical trial data and epidemiological impact of Hib and pneumococcal conjugate vaccines.
Main Results:
- Conjugation of polysaccharides to carrier proteins enhances immunogenicity in young children.
- Conjugate Hib vaccines significantly reduce Hib meningitis and invasive disease.
- Pneumococcal conjugate vaccines effectively prevent invasive disease from vaccine-contained serotypes.
Conclusions:
- Conjugate polysaccharide vaccines are a vital tool for protecting young children against serious bacterial infections.
- Further efficacy studies are ongoing for meningococcal conjugate vaccines.
Abstract:
Conjugate polysaccharide vaccines are a recent intervention to combat the relative inability of young children to mount an effective immune response against encapsulated bacteria, especially Haemophilus influenzae (Hib), Neisseria meningitidis (Nm) and Streptococcus pneumoniae (Sp). These organisms cause the majority of community acquired septicaemia and meningitis in UK children. Their capsular polysaccharides, important virulence factors in evading phagocytosis, are poorly immunogenic in young children compared to adults. Conjugation, by covalent linking, of the polysaccharide to an immunogenic protein, has been demonstrated for each of these organisms to produce good antibody response to the polysaccharide. Conjugate Hib vaccines have proven effective in reducing Hib meningitis and invasive disease in the countries that have introduced them. Pneumococcal conjugate vaccines have proven effective in preventing invasive disease caused by serotypes contained in the vaccines. Efficacy studies are awaited for meningococcal conjugate vaccines.