For each of the three families, the infection rate was not associated with gender (Fisher's exact test p = 0.164, 0.260, 0.289 for K1, Mad20 and RO33, respectively), β-globin type (Fisher's exact test p = 0.498, 0.704 and 0.384 for K1, Mad20 and RO33 respectively), ABO blood group (Fisher's exact test p = 0.195, 0.721 and 0.467 for K1, Mad20 and RO33, respectively) and Rhesus blood groups (Fisher's exact test p = 1.000, 0.268 and 0.370 for K1, Mad20 and RO33, respectively). Here, ABO is linked to infection.