For over 20 years children with sickle cell anemia have been known to have an increased susceptibility to severe bacterial infection, particularly due to Streptococcus pneumoniae. Meningitis, pneumonia and septicemia due to this organism have been recognized as the major causes of death for these children, with children under three years of age being at highest risk. The annual incidence of pneumococcal septicemia among young children with sickle cell anemia appears to have remained remarkably constant over the last two decades at approximately 10 percent. This illness can often be fulminant, progressing from the onset of fever to death in less than 12 hours, with a case fatality rate ranging as high as 35 percent.