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. Check for active clinical trialsusing this agent.