Trial Parameters
Brief Summary
The primary goal of this study is to complete a multicenter single-arm, type I hybrid trial to assess the effectiveness of hydroxyurea therapy for primary stroke prevention in high-risk children with sickle cell anemia (SCA) living in Nigeria in routine care settings.
Eligibility Criteria
Inclusion Criteria: The inclusion criteria for the SPRING-2 Trial will consist of: * Diagnosis of HbSS or HbSB0 confirmed by high-performance liquid chromatography (HPLC); * Informed consent from the parent/legal guardian and assent from the patient at least 7 years of age; * Two TCD flow velocity readings of \>or equal to180 cm/sec and \< 220 cm/sec or one TCD velocity reading \> or equal to 220 cm/sec; typically the repeat TCD is performed on the same day so treatment can start immediately; * Age between 5 and 12 years (assessment can take place up until the 13th birthday), which includes the peak age of onset of strokes in SCA, \~ 6 yo; and * Ability to swallow the hydroxyurea capsule. Exclusion Criteria: The exclusion criteria will be the following: * Prior stroke or TIA by history, or concern for moderate or severe neurological deficit based on a positive validated "10 questions" screening; * Other significant organ system dysfunction or other contraindication to hydroxyurea; * Ch