Pneumococcal Vaccine

Like other meningitis bacteria, the pneumococcus is covered by a capsule or coat made of a complex sugar called a polysaccharide. Although there are 84 different types of pneumococci, most cases of disease are caused by a much smaller number.

A polysaccharide vaccine is used in children, adolescents, and adults at increased risk of pneumococcal disease and is recommended for all those over 65 years of age. It contains purified polysaccharides against 23 strains of the pneumococcus which cause over 85% of all disease in older children and adults. Three brands of the polysaccharide vaccine are available:

            Pneumo 23®
            Pneumovax 23®
            Pnu-Immune 23®

Like almost all polysaccharide vaccines, the pneumococcal polysaccharide vaccine does not work in children under two years of age. A new vaccine for infants has been developed in which the purified polysaccharide is chemically linked to a protein (Prevnar®7). The original vaccine contains seven different polysaccharides from the seven strains which cause over 85% of severe pneumococcal infections in infants and young children in USA and Canada. The vaccine also reduced the frequency of cases of otitis media (ear infections) by 20%. The vaccine was licensed for use in the United States in February 2000 and in Canada in June 2001. The original vaccine has recently been replaced by a new vaccine containing the original 7 types and an additional 6 types [Prevnar®13]. The expansion to pneumococcal conjugate vaccine 13 was required because although the 7-component vaccine was very effective in preventing disease caused by the 7 types in the vaccine, it did not protect against other types of pneumococci. Moreover, like the meningococcal and Hib conjugate vaccine, the pneumococcal conjugate vaccine not only protects the vaccinated individual against disease, it also protects against becoming a carrier of one of the vaccine strains. Therefore not only disease, but also carriage of the 7 vaccine types decreased in wherever routine infant vaccine programs were introduced. By adding 6 additional types to the original seven, it will be possible to keep the frequency of serious pneumococcal infections at a very low level.

The new vaccine is very effective in preventing pneumococcal infections. In a study of over 37,000 infants in California immunized with the new pneumococcal conjugate vaccine at 2, 4, 6, and 12-15 months of age, the vaccine was 97% effective in preventing bacteremia (infection of the blood stream) and meningitis. The rate of severe pneumonia was reduced by 33%. Since routine vaccination of infants became routine in the USA, the rate of serious pneumococcal infections in children less than 5 years of age has decreased 94%. Because the vaccine also reduces carriage of the vaccine strains, the spread of these strains has been reduced in all age groups. As a result, the rate of serious pneumococcal infections caused by the vaccine serotypes has decreased in all age groups, not just in vaccinated children. Among those over 65 years of age, the rate of severe pneumococcal infections caused by the vaccine strains has decreased by 65%.

The new vaccine is very effective in preventing pneumococcal infections. In a study of over 37,000 infants in California immunized with the new pnuemococcal conjugate vaccine at 2, 4, 6, and 12-15 months of age, the vaccine was 97% effective in preventing bacteremia (infection of the blood stream) and meningitis. The rate of severe pneumonia was reduced by 33%. Since routine vaccination of infants became routine in the USA, the rate of serious pneumococcal infections in children less than 5 years of age has decreased 94%. Because the vaccine also reduces carriage of the vaccine strains, the spread of these strains has been reduced in all age groups. As a result, the rate of serious pneumococcal infections caused by the vaccine serotypes has decreased in all age groups, not just in vaccinated children. Among those over 65 years of age, the rate of severe pneumococcal infections caused by the vaccine strains has decreased by 65%.

The pneumococcal conjugate vaccine is recommended for routine immunization of all infants at 2, 4, and 6 months of age, followed by a booster at 18 months of age. Many provinces have changed to a three dose schedule for infants at 2, 4, and 12 months of age. The 3-dose shcedule has been shown to be as effective as the original four dose schedule. Catch-up programs to immunize older infants and children less than 5 years of age will require 1 or 2 doses of vaccine, depending on the age of the child at the time of first vaccination. Since November 2005, the vaccine is available in all provinces and territories as part of the routine childhood immunization schedule at no cost to parents. It has proven to be as effective in Canada as it has been in the USA.

Routine use of the conjugate vaccine can make meningitis and other severe pneumococcal infections become rare events in Canadian children.

http://www.meningitis.ca/en/PneumococcalVaccine
Phone or Fax - (519) 664-0244
or Toll-free 1-800-643-1303
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