Evaluation of pneumococcal conjugate vaccine (Prevenar®) inpatients with myeloma and chronic lymphocytic leukaemia

Infection with Streptococcus pneu1110niae is responsible for significant mortality in individuals with a defective humoral response. This diverse group includes patients with the haematological conditions myeloma and chronic lymphocytic leukaemia. Vaccination to prevent pneumococcal infection is recommended by the Department of Health for those individuals in whom disease is likely to be 'more common and/or more dangerous'. The currently recommended 23-valent polysaccharide vaccine has been shown to be poorly immunogenic in patients with myeloma and chronic lymphocytic leukaemia. Responses to vaccination may be improved by conjugation of polysaccharides to immunogenic carrier proteins. Prevenar©, a 7-valent conjugate vaccine has been demonstrated to be immunogenic both in young children and in adults following allogeneic bone marrow transplantation. These groups had both previously been shown to respond poorly to the 23-valent polysaccharide vaccine. A clinical trial was designed to evaluate the use of Prevenar in individuals with myeloma and chronic lymphocytic leukaemia. Serological response to the vaccine was the primary end-point determined by a recently evaluated pneumococcal serotype-specific Bioplex assay. In addition the serological response to the protein carrier was also evaluated using a newly developed assay. The vaccination programme resulted in statistically significant increases in serotype-specific antibody levels. For a proportion of trial participants this represented adequate protection. The immunogenicity of the conjugate vaccine was modest however when compared to the published data in other clinical scenarios. The suboptimal response was most likely to have been related to the deficient cell mediated and humoral immunity observed in this population. More detailed evaluation of these parameters may identify individuals who are more likely to respond to the conjugate vaccine.EThOS - Electronic Theses Online ServiceGBUnited Kingdo