Assessment of the antibody response to pneumococcal vaccine in high-risk populations.

Vaccine-induced levels of antibody to Streptococcus pneumoniae of approximately 250-300 ng of antibody nitrogen/ml are protective against pneumococcal disease. Side effects of vaccination are not severe and are generally confined to local reactions at the site of inoculation. Patients with a documented high risk of acquiring pneumococcal disease include the elderly, especially those with underlying cardiopulmonary disease, and those with sickle cell anemia, Hodgkin's disease, a renal transplant, multiple myeloma, asplenia, and nephrotic syndrome. People with insulin-dependent diabetes mellitus or renal failure do not appear to be at high risk. All of these groups, except those with multiple myeloma, respond to vaccine with levels of antibody that are protective for many but not all of the serotypes included in the vaccine. Immunosuppression, splenectomy, and hemoglobinopathy depress antibody response. Duration of vaccine-induced antibody is unknown but may be shorter than that in normal persons. Preliminary guidelines for vaccination are proposed.