The pneumococcal polysaccharide vaccine is one of two vaccines used to prevent infection by Streptococcus pneumoniae, bacteria that cause middle ear infections, pneumonia, meningitis and bacteremia (infection in the blood). Infections caused by Streptococcus pneumonia were effectively treated with antibiotics. However, more infections are becoming resistant to the antibiotics, prompting a need for prevention by vaccines. The World Health Organization estimates that nearly 1 million children each year die from pneumococcal infections. The mixture of ingredients in the pneumococcal polysaccharide vaccine is effective in preventing 57 percent to 75 percent of infections, according to the National Network for Immunization Information.
Microorganism
The pneumococcal polysaccharide vaccine is made using extracts of the outer polysaccharide (a polysaccharide is a long chain of sugar molecules) coating the bacteria. These polysaccharides then trigger the formation of antibodies against the bacteria, which then attack the bacteria before infection can be caused.
Vaccines that are made of pure polysaccharide extracts aren't effective in children younger than 2. Infants don't have an immune system that's mature enough to produce antibodies to the polysaccharides. This is why there is another pneumococcal vaccine available to protect young children.
The pneumococcal polysaccharide vaccine contains a mixture of material from 23 different types of Streptococcus pneumonia bacteria. Ninety different types of this bacteria are identified, but the 23 included in the vaccine cause 85 percent to 90 percent of the serious pneumococcal infections, according to the National Network for Immunization Information.
Preservative
Preservatives are used to keep the vaccine solution free from contamination from fungus or bacteria. In the past, all vaccines were manufactured with preservatives. However, with the controversy over some of the more popular preservatives--such as thimerosal, which contained mercury--and the fact that vaccines are now packaged in single dose vials, reducing the chance of contamination, more vaccines are manufactured without preservatives.
The pneumococcal polysaccharide vaccine contains one preservative, a 0.25 percent solution of phenol. Phenol is a natural substance and a manufactured chemical that can be very toxic in large quantities. Phenol is used to create disinfectants and antiseptics because of its ability to prevent the growth of bacteria.
Adjuvant
Many vaccines also include an adjuvant as an ingredient. The adjuvant is a compound that enhances the vaccine, providing immunity with the use of less vaccine. Adjuvants may help carry the vaccine components to the cells in the body, or it may help the cells better absorb the components. The pneumococcal polysaccharide vaccine, however, does not include an adjuvant as one of its ingredients.
Media
The polysaccharide components used in the vaccine must be cultured during the manufacturing process. This requires the use of media, which then becomes an ingredient of the vaccine. For the pneumococcal polysaccharide vaccine, bovine protein is used in culture and is therefore an ingredient.
