Pneumococcal bacteremia in infants and children: a ten-year experience at the Cook County Hospital with special reference to the pneumococcal serotypes isolated.

In a ten-year period we identified 305 hospitalized children with a pneumococcal bacteremia. From these children 293 pneumococcal isolates were serotyped, and 90% belonged to a group of 11 "prevalent serotypes." These 11 serotypes were the prevalent serotypes isolated from children in all disease categories, as well as from children with sickle-cell disease. No more than 1% of the isolates belonged to any one of the other serotypes. A pneumococcal vaccine effective against these 11 prevalent serotypes should be optimal for use in children. Our highest case fatality rates were noted in children with meningitis (13%) and children with sickle-cell disease (20%). A polysaccharide pneumococcal vaccine might not have prevented most of our pneumococcal meningitis, as 80% of these children were less than 1 year old, an age when polysaccharide vaccines are poor antigens. On the other hand, many of our children with sickle-cell disease acquired their pneumococcal bacteremia at an older age and should have benefitted from such a vaccine.