Haiti and the study environment. Port-au-Prince is Haiti’s capital, with 2.9 million inhabitants (2022 data)¹⁰ with a poverty level of 87.6% and 30.3% of the population living under the extreme poverty line.¹¹ Social factors include street violence and suboptimal literacy rate for Haiti, in general, with 61.7% literacy for individuals aged ≥15 years and 83% literacy for the subgroup of individuals aged 15 to 24 years.¹² SDH, the only pediatric hospital in Haiti, has a 224-bed capacity. The hospital serves 1000 children with SCD, from infancy to age 12 years. The SDH laboratory has a Sebia capillary hemoglobin electrophoresis machine and a Perkin Elmer IEF machine in use for NBS. HUEH does not have capacity for hemoglobinopathy evaluation and outsources samples to SDH. Thirty children with SCD are examined at HUEH. JUH is located at Cap Haitien, Haiti’s second largest city after Port-au-Prince, with 190 000 inhabitants.¹⁰ This program has a nurse coordinator and CHW, serving 30 children with SCD. Located at Milot, a rural town of 25 100 inhabitants,¹³ 11 miles south from Cap Haitien, SCH does not have hemoglobinopathy laboratory equipment; >200 children are followed up at SCH. None of the 4 hospitals had a TCD ultrasound machine before the CSHSCD started. Hydroxyurea was purchased from outside vendors (rarely) or supplied by sponsors. Before the CSHSCD, penicillin was administered by intramuscular injection every month as pneumococcal prophylaxis for children aged <5 years.