Blood-Group-A-Like Substance in a Preparation of Pneumococcal Vaccine

Abstract

A platelet transfusion from a blood group O donor, immunized 1 month before with Pneumovax, caused a hemolytic reaction in a blood group A recipient. Forty-five of 59 group O donors (76%) and all of nine group B donors immunized with Pneumovax had a fourfold or higher anti-A response. Half of the anti-A antibody in high titered donors was in the IgG fraction. Pneumovax contained approximately 30 µg of an A-like substance per dose; polyvalent pneumococcal vaccines prepared by two other manufacturers contained very low and probably subimmunogenic concentrations. Several culture media prepared from animal tissues contained an antigen of similar physical, immunologic, and chemical properties, and were the most likely source of the contaminant. Manufacturing procedures have since been revised to eliminate A-like substances.