Morbidity and mortality in pediatric sickle cell disease (SCD) in the United States have markedly declined since the 1970s. Initial impact from newborn screening for presymptomatic diagnosis, early initiation of preventative care, and widespread initiation of disease-modifying therapies have led to reduced early mortality and reduced childhood morbidities. Nonetheless, several specific complications remain that are partially or entirely specific to pediatric SCD. Persistence of these complications is related to their early onset and structural and physiologic factors, especially dactylitis and splenic sequestration. Moreover, children with SCD remain especially susceptible to bacterial infections, likely due to early and ongoing decreases in splenic function. Here, we highlight the historical implementation of newborn screening for SCD and disease complications that exclusively or predominately affect children.
Newborn Screening for SCD
Newborn screening for SCD plays a crucial role in the successful survival of children with SCD in North and South America, Western Europe, and elsewhere.1-4 Universal screening also enables population surveillance for public health tracking and planning. Here, we review the rationale for, impact of, and opportunities arising from population-based hemoglobinopathy screening, as well as the potential for future research and intervention. In this chapter, we focus primarily on the United States, with limited discussion of the successful efforts to develop newborn SCD screening in sub-Saharan Africa and India, where most children with SCD are born. International progress is described in another chapter.
The foundation of newborn screening is based on the principles that (1) early diagnosis of specific inherited diseases can allow presymptomatic initiation of appropriate therapy during a window of health to safeguard well-being and development and (2) clinical detection in the absence of newborn screening will delay diagnosis and worsen outcomes.1,5 The model of newborn screening arose in the 1960s and 1970s from the collective efforts of scientists and the public to prevent the developmental effects on infants affected by phenylketonuria (PKU). For PKU, avoiding dietary exposure to phenylalanine led to markedly improved pediatric outcomes. Laboratory screening in centralized laboratories is performed from collected dried bloodspots. Samples are universally obtained prior to discharge from the newborn nursery of birth hospitals.
To reach broad public access to the benefits of newborn screening, testing capacity at state public health laboratories was established. In addition, screening programs developed avenues of rapid communication with birth hospitals, pediatric providers, and parents of infants suspected of being affected by SCD or other screened health condition. To partner with specialists to provide health care for the needs of identified children, each state designates specialty centers at one or more hospitals to provide confirmatory testing and prompt access to treatment. For SCD, each state has identified hemoglobinopathy centers to provide access to expert comprehensive specialized pediatric SCD care. As a public health program, parental consent is not required for routine infant screening.6