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PREVENTION OF PNEUMOCOCCAL PNEUMONIA BY IMMUNIZATION WITH SPECIFIC CAPSULAR POLYSACCHARIDES
C M Macleod1, R G Hodges, M Heidelberger
1Department of Bacteriology, New York University College of Medicine, New York, The Army Air Force Rheumatic Fever Control Program, Office of The Air Surgeon, and the Department of Medicine, College of Physicians and Surgeons of Columbia University, New York.
The Journal of Experimental Medicine
|October 30, 2009
Summary
Pneumococcal polysaccharide immunization effectively prevents pneumonia from specific pneumococcus types. This vaccination also reduces the carrier rate of these bacteria, indirectly benefiting unvaccinated individuals.
Area of Science:
- Microbiology
- Immunology
- Public Health
Background:
- Pneumonia remains a significant public health concern, often caused by Streptococcus pneumoniae.
- Capsular polysaccharides are key virulence factors for pneumococcus.
- Effective vaccines are crucial for controlling pneumococcal disease.
Purpose of the Study:
- To evaluate the efficacy of pneumococcal capsular polysaccharide immunization in preventing pneumonia.
- To assess the impact of immunization on pneumococcus carrier rates.
- To determine the onset and minimum duration of vaccine-induced immunity.
Main Methods:
- Human subjects were immunized with capsular polysaccharides from pneumococcus types I, II, V, and VII.
- Pneumonia incidence was monitored in immunized and non-immunized groups.
- Carrier rates for targeted pneumococcus types were assessed in both groups.
- Immunity onset and duration were evaluated post-immunization.
Main Results:
- Immunization with 0.03-0.06 mg of each polysaccharide type prevented type-specific pneumonia.
- Immunity developed within 2 weeks, with a minimum duration of 6 months.
- Vaccination of alternate subjects significantly reduced pneumonia incidence in the unvaccinated.
- Carrier rates for pneumococcus types I, II, V, and VII were significantly lower in the immunized group.
Conclusions:
- Pneumococcal polysaccharide vaccines are effective in preventing type-specific pneumonia.
- Immunization reduces nasopharyngeal carriage of targeted pneumococcus strains.
- Reduced carrier rates may contribute to herd immunity, lowering overall disease incidence.
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