Dot plot showing geometric mean parasite densities within the 25%, 50%, 75% and >75% quartile ranges for boys and girls of HbAS genotype.

This data came from multiple sick visits with the 265 days follow-up period. Due to the high variability and with a wide range of parasitemia data, analysis was done at different distribution quartiles. At all the quartile ranges 25%, 50% and 75% (panels A, B and C respectively) the parasite geometric mean for females of HbAS/αα/αα genotype was much higher than for males. As shown in panel C, the median parasite density within the third quartile was two times higher in females of HbAS/αα/αα genotype (3,118, 95% CI: 1779–5465) than for males (1,676, 95% CI: I752-3733). This trend was maintained across the ordered α-thalassemia genotypes (Kurskal-Wallis; 0.0422). A second loss of α+-thal gene increased the parasite load even further. Each dot represents parasitemia from a sick visit from the patients.