Pneumococcal infections and sickle cell disease in Africa: does absence of evidence imply evidence of absence?

Sickle cell disease (SCD) compromises host immune defence and predisposes to infections from several encapsulated bacteria, viruses and parasites. While penicillin prophylaxis and pneumococcal vaccination are established routine care in developed countries, such preventive measures are poorly structured or non-existent in most malaria-endemic, developing country settings. In fact, the role of pneumcoccal infections has been brought into question, based on available data. The role of invasive pneumococcal disease in child mortality has now been established from population-based studies in such settings. Thus, it may be unsafe to assume that children with SCD are less susceptible. Whether malaria endemicity increases susceptibility to other encapsulated bacteria such as salmonella infections is a critical but unanswered question that will inform the development of appropriate preventive measure policies in this setting. Research to clearly define the leading cause of infection-related morbidity and mortality in SCD in Africa should be encouraged.