NCIt definition : An active immunizing agent used to prevent infection by the bacterium Streptococcus
pneumoniae. Pneumococcal 7-valent conjugate vaccine consists of a solution of saccharides
of the capsular antigens of Streptococcus serotypes 4, 6B, 9V, 14, 18C, 19F, and 23F
individually conjugated to diphtheria CRM 197 protein.;