Conjugate polysaccharide vaccine is linked to a protein
Available vaccines
Hib (conjugate vaccine)
conjugated to an immunogenic protein, such as diphtheria toxoid.
Pneumococcal vaccine
PCV13 (conjugate vaccine)
PPSV23 (unconjugated vaccine)
Meningococcal vaccine (conjugate vaccine; various strains of Neisseria meningitidis)
Mechanism of action
Polysaccharides induce a relative T cell-independent B-cell response and therefore achieve sufficient immunization only in adults and older children.
In conjugate vaccines, the carrier protein activates T-cells, which stimulate a more rapid and long-lasting immune response, especially in infants and toddlers.