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Pneumococcal serotypes causing bacteremia and meningitis: relevance to composition of pneumococcal vaccine
Abstract:
The capsular type of 160 strains of pneumococci isolated from blood or cerebrospinal fluid of patients in Alberta and Ontario between June 1978 and August 1980 was determined. Of the 83 known serotypes 36 were represented, and the type distribution was similar to that reported from the United Kingdom and the United States. Although only 111 (69.3%) of the strains belonged to the serotypes represented in the licensed pneumococcal vaccine, if related types within the same serogroup are also included 132 (82.5%) of the strains belonged to the types or groups represented in the vaccine, However, because the vaccine is not recommended for persons aged less than 2 years, from whom 30 strains were isolated, and because 28 strains from those 2 years of age and older were of nonvaccine types or groups, one can presume that 58 (36.3%) of the 160 bacteremic and meningitic infections would not have been prevented by prior vaccination, even if the vaccine were completely effective.
Insights
Pneumococcal serotypes causing infections in Canada show similarities to other countries. However, a significant portion of invasive pneumococcal disease strains were not covered by the available vaccine in the late 1970s.
Area of Science:
- Microbiology
- Immunology
- Epidemiology
Background:
- Streptococcus pneumoniae (pneumococci) causes serious infections like bacteremia and meningitis.
- Capsular typing is crucial for understanding pneumococcal epidemiology and vaccine development.
Purpose of the Study:
- To determine the capsular serotype distribution of pneumococci isolated from invasive infections in Canada.
- To assess the coverage of existing pneumococcal vaccines against these circulating strains.
Main Methods:
- Serotyping of 160 pneumococcal isolates from blood or cerebrospinal fluid.
- Comparison of Canadian serotype distribution with data from the UK and US.
- Evaluation of vaccine strain coverage, including related serogroups.
Main Results:
- 36 of 83 known pneumococcal serotypes were identified in the Canadian isolates.
- Serotype distribution was comparable to that reported in the United Kingdom and United States.
- While 69.3% of strains matched vaccine serotypes, 82.5% matched vaccine serotypes or related groups.
- A substantial number of infections (36.3%) were caused by non-vaccine types or groups, particularly in children under 2 and older individuals.
Conclusions:
- The circulating pneumococcal serotypes in Canada during 1978-1980 had similarities to other regions.
- The pneumococcal vaccine available at the time would not have prevented a significant proportion of invasive infections due to non-vaccine serotypes.
- These findings highlight the need for ongoing surveillance and potentially broader-spectrum vaccines to combat pneumococcal disease.