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Sickle cell anemia predisposes children to bacteremic infections. More than 80% of children born with this disease reside in Africa. To better characterize the burden and causes of bacteremic infections among African children with sickle cell disease, investigators undertook a case-control study in rural Kenya.
Blood cultures were performed for children aged <14 years who lived within a defined geographic area and were hospitalized between August 1, 1998, and March 31, 2008. Children found to be bacteremic were tested for sickle cell anemia. Those with sickle cell anemia (defined as absence of hemoglobin A [found in sickle cell trait] and PCR-confirmed presence of hemoglobin S) were considered cases. Controls — healthy children drawn from the same area — were also tested for sickle cell anemia.
Of 38,441 children admitted during the study period, 2157 had documented bacteremia. Genotyping of blood samples showed sickle cell anemia in 108 (6%) of the 1749 bacteremic children tested (vs. 1% of the 13,492 controls). Among these 108 children, the most common causes of bacteremia were Streptococcus pneumoniae (41%), non-typhi Salmonella species (18%), and Haemophilus influenzae type b (Hib; 12%). Seventy-five percent of the pneumococcal isolates were serotypes included in the licensed 10-valent pneumococcal conjugate vaccine.
For 80 of the 108 children with sickle cell anemia, the diagnosis had not been made before this admission. The children with sickle cell anemia were significantly more likely than controls to develop bacteremia (age-adjusted odds ratio, 26.3; 95% confidence interval, 14.5–47.6).
Williams TN et al. Bacteraemia in Kenyan children with sickle-cell anaemia: A retrospective cohort and case–control study. Lancet 2009 Sep 10; [e-pub ahead of print]. (http://dx.doi.org/10.1016/S0140-6736(09)61374-X)
Hankins J and Ware RE. Sickle-cell disease: An ounce of prevention, a pound of cure. Lancet 2009 Sep 10; [e-pub ahead of print]. (http://dx.doi.org/10.1016/S0140-6736(09)61602-0)
Comment
Although the full burden of bacteremic infections is likely underestimated, this study documents that such infections are an important cause of morbidity in African children with sickle cell anemia, and that the predominant organisms are similar to those seen in developed countries. Because pneumococcal and Hib infections are vaccine preventable, immunization should have high priority for this population. The authors and editorialists note the potential benefit from early screening for hemoglobinopathies.