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Prospects for the prevention of bacterial meningitis with polysaccharide vaccines
Abstract:
MOST SUPPURATIVE INFECTIONS OF THE MENINGES ARE CAUSED BY FIVE BACTERIAL SPECIES: Escherichia coli, Haemophilus influenzae type b, Streptococcus pneumoniae, Neisseria meningitidis, and group B streptococcus. The immune response of adults to pneumococcal capsular polysaccharides has been studied in great detail and their responses to meningococcal and H. influenzae type b capsular polysaccharides are quite similar. Immune responses of adults to E. coli and group B streptococcal antigens are disappointing. The responses of children below the age of 7 years differ both quantitatively and in duration. Early experience shows that useful antibody titres can be achieved with certain antigens but further studies are required. In order to prevent bacterial meningitis by immunization, three vaccine formulations will need to be developed. When epidemic meningococcal disease occurs in a population, the vaccine containing only components of the meningococcus would be applied to a large segment of the population to terminate the epidemic. The second vaccine would contain components of H. influenzae type b, pneumococcus, and the meningococcus and would be administered in the first year of life, and repeated at suitable intervals to maintain life-long immunity. The third vaccine, designed to prevent neonatal meningitis caused by E. coli K1 and group B streptococci, would be administered to women preferably during the third trimester of pregnancy, so that their offspring would inherit sufficient antibodies to protect them during the first 3 months of life.The vaccine against the meningococcus is a reality and has been used extensively during major epidemics, with excellent results. The two vaccines for control of endemic bacterial meningitides do not exist as yet, but the prospects are good.
Insights
Bacterial meningitis is caused by five key bacteria. Developing three new vaccines targeting these pathogens, including one for pregnant women, shows promise for preventing childhood and epidemic meningitis.
Area of Science:
- Bacteriology
- Immunology
- Vaccinology
Background:
- Suppurative meningitis is primarily caused by five bacterial species: Escherichia coli, Haemophilus influenzae type b, Streptococcus pneumoniae, Neisseria meningitidis, and group B streptococcus.
- Adult immune responses to pneumococcal, meningococcal, and H. influenzae type b capsular polysaccharides are well-characterized, but responses to E. coli and group B streptococcal antigens are less effective.
Purpose of the Study:
- To outline the development of three distinct vaccine formulations for the prevention of bacterial meningitis.
- To address the differing immune responses in children and adults to various bacterial antigens.
Main Methods:
- Review of existing knowledge on immune responses to bacterial meningitis pathogens.
- Proposal for three novel vaccine strategies targeting specific bacterial species and age groups.
Main Results:
- A vaccine against Neisseria meningitidis is currently available and effective for epidemic control.
- Prospects are good for developing vaccines against H. influenzae type b, Streptococcus pneumoniae, E. coli K1, and group B streptococcus.
Conclusions:
- Three vaccine formulations are needed to combat bacterial meningitis: one for meningococcal epidemics, one for endemic H. influenzae type b, pneumococcus, and meningococcus in infants, and one for neonatal E. coli K1 and group B streptococcus meningitis administered to pregnant women.