Meta-analysis of studies examining the relationship between Hp type and severe malaria. Forest plots showing a meta-analysis of eligible case-control studies that have examined the relationship between Hp type and the risk of severe malaria for (A) Hp2-2 vs Hp1-1; (B) Hp2-2 vs Hp2-1; and (C) Hp1-1 vs Hp2-1. Individual estimates and the relative contribution of the individual studies to the overall estimates (percentage weight and numbers in each group) are shown. *The frequency of the –α/ allele in the relevant country. The studies by Aucan et al¹⁷  and Bienzle et al¹⁸  do not report the prevalence of α⁺thalassemia in their study populations, and the prevalences shown (0.12 in The Gambia³⁹  and 0.33 in Ghana⁴⁰ ) are from other studies within the same country. Further Forest plots show the results of the current study stratified by α⁺thalassemia status.