Survival of children with SS and Sβ°. Shown are overall survival (A), SCD-related mortality (B), and stroke-free survival (C). Numbers above the x-axes indicate the number of subjects remaining at risk at a particular age. Dotted lines delimit the 95% CIs. (D) Overall survival curves for the Jamaican cohort study of SCD (SS only), the CSSCD infant cohort (SS only), and the Dallas Newborn Cohort (SS and Sβ°). Vertical bars indicate upper or lower boundaries of the 95% CIs (one direction omitted for clarity). The survival curve for the CSSCD infant cohort was published for approximately 4 years of observation only.¹¹  The Jamaican cohort was divided into thirds based on date of birth. Subjects in the first third (1973-1975) did not routinely receive prophylactic PCN, whereas subjects in the middle (1975-1979) and last (1979-1981) thirds did receive PCN. Survival curves are shown only for the first and last third of the Jamaican cohort.