National Center for Biotechnology Information NCBI NLM MEDLINE humans pubmed abstract nih national institutes of health national library of medicine research support non-u.s. gov't female male Child Infant preschool risk factors case-control studies streptococcus pneumoniae / genetics hiv infections / drug therapy pneumococcal infections / prevention & control* hiv infections / immunology* streptococcus pneumoniae / classification south africa / epidemiology pneumococcal infections / immunology serogroup pneumococcal infections / epidemiology pneumococcal vaccines / immunology* pmid:24917657 pmc4144265 doi:10.1093/cid/ciu431 cheryl cohen claire von mollendorf south african invasive pneumococcal disease case-control study group coinfection* pneumococcal vaccines / administration & dosage