Pneumococcal conjugate vaccine or Prevnar is a vaccine use to protect infants and young children against disease caused by the bacterium Streptococcus pneumoniae (pneumococcus). Prevnar is a heptavalent vaccine, meaning that it contains the cell membrane sugars of seven serotypes of pneumococcus, conjugated with Diphtheria proteins. It is manufactured by Wyeth as the brand name Prevnar. In the United States, vaccination with Prevnar is recommended for all children younger than 2 years, and for unvaccinated children between 24 and 59 months old who are at high risk for pneumococcal infections.