[Serotype 5 pneumococcus in epidemiology and vaccine]

Abstract

The Streptococcus pneumoniae serotype 5 is commonly isolated in human pathology. In France, it is the fourth pneumococcal serotype for acute pneumonia (9.1%) and bacteremia (6.9%). It appears to be more frequently encountered in Africa: in Dakar, this serotype is the third pneumococcal agent and is one of the more often isolated in meningitis; moreover, its is the third serotype isolated in Nigeria. In the intention of its incorporation in the yet available 14-valent pneumococcal vaccine, we have compared serological response and tolerance among four groups of adults: 1) the first group (23 persons) was only immunized by serotype 5 pneumococcal polysaccharide (50 micrograms); 2) the second group (23 persons) by the 15-valent pneumococcal vaccine (14-valent + serotype 5); 3) the third and the fourth groups (21 and 97 persons) were immunized by the 14-valent pneumococcal vaccine. By comparing the multiplying factors of geometrical means of antibodies levels measured by RIA, it appears that the pneumococcal polysaccharide serotype 5 is immunogenic, dispensed alone (first group) or associated with 14-valent pneumococcal vaccine (second group). No reciprocal interference can be detected between this polysaccharide and the other 14 polysaccharides. The tolerance of the serotype 5 polysaccharide is as good as that of these 14 antigens.