Antibody response to pneumococcal vaccination in patients with myelomatosis.

17 patients with myelomatosis were vaccinated with a 14-valent pneumococcal capsular polysaccharide vaccine. In comparison to 12 healthy controls, they had statistically significant lower combined geometric mean antibody concentrations (the geometric means of all 14 antigens), both before and 4 weeks after the immunization. Mean antibody increases, however, were remarkably similar in the 2 groups. After 18 months the geometric mean antibody concentrations of the patient group had returned to preimmunization levels or lower for 7 out of 14 antigens. 1 case of pneumococcal bacteraemia occurred in the patient group 8 1/2 months after vaccination in spite of a significant initial antibody response against the infecting serotype 23 F. Pneumococcal vaccination in patients with myelomatosis appears to yield subnormal antibody responses and therefore probably insufficient protection against pneumococcal infection.