Revaccination with polyvalent pneumococcal vaccine in children with sickle cell anemia.

To determine if revaccination improves levels of antibodies to pneumococcal polysaccharide types 6A, 14, and 19, 86 subjects with sickle cell anemia between 4 and 23 years old were given a booster injection of a polyvalent pneumococcal vaccine 37 to 53 months after primary immunization. Most subjects had mild local reactions similar to those seen after primary immunization. Only two subjects, both young adults, had severe local and systemic reactions. The percentages of subjects with protective antibody levels to types 6A, 14, and 19 increased from 74%, 44%, and 79% respectively before boosting, to 92%, 66%, and 92% respectively after boosting. Revaccination of children and young adults with sickle cell anemia appears to result in increased protective levels of antibody, and is associated with a low prevalence of severe reactions.