Tolerability and Immunogenicity of an 11-valent Pneumococcal Conjugate Vaccine in Adults

We studied the safety and immunogenicity in healthy adults of an 11-valent pneumococcal conjugate vaccine. Capsular polysaccharides (PS) of serotypes 1, 4, 5, 7F, 9V, 19F and 23F were conjugated to tetanus toxoid, and of serotypes 3, 6B, 14 and 18C to diphtheria toxoid. Ten subjects received the conjugate vaccine with and the other ten subjects without aluminium hydroxide adjuvant. The reference vaccine was a marketed 23-valent PS vaccine. Safety data were recorded over 5 days after the immunisation. IgG antibody concentrations, avidity and subclass distribution were measured by EIA. The conjugate without aluminium induced more local adverse effects than the conjugate with aluminium or PS vaccine. All vaccines evoked significant antibody increases to all vaccine specific antigens. Both conjugate vaccines induced antibodies mainly of IgG(2) subclass, and adjuvanted conjugate vaccine induced IgG antibodies with increased avidity. This first administration, to man, of a mixed protein carrier 11-valent pneumococcal conjugate vaccine demonstrated its ability to induce an immune response without significant adverse effects, enabling further study on its use in paediatric populations.