Researchers have identified differences in the genetic code of pneumococcal bacteria that may explain why it poses such a risk to children with sickle cell disease and why current vaccines don't provide better protection against the infection. St. Jude Children's Research Hospital scientists led the study, which appeared earlier this month in the journal Cell Host & Microbe.
The findings will aid efforts to improve vaccine effectiveness and inform research into new ways to protect young sickle cell disease patients from life-threatening pneumococcal infections that can lead to pneumonia, meningitis, bloodstream infections and other problems. Despite advances in preventive care, including vaccination and prophylactic antibiotic therapy, pneumococcal infections still pose a serious health risk to children with sickle cell disease, who are at a much greater risk of possibly fatal infection than are members of the general public.
The results followed whole genome sequencing of hundreds of pneumococcal bacteria collected from the public and patients with sickle cell disease. The genome is carried in the DNA molecule and includes the instructions necessary to assemble and sustain life.
The analysis showed the bacteria have adapted to sickle cell patients, including measures aimed at preventing infection. As a result, disease-causing strains of the bacteria differ in children with and without sickle cell disease. For example, the pneumococcal strains collected from sickle cell patients in this study differed from the 13 pneumococcal strains included in the current vaccine recommended for children age 5 and younger.
"The results help explain why current vaccines haven't been as successful at protecting children with sickle cell disease from pneumococcal infections as they have in protecting other children," said Joshua Wolf, M.D., an assistant member of the St. Jude Department of Infectious Diseases and one of the study's lea
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St. Jude Children's Research Hospital