Giardiasis was found to be significantly associated with MPO (Coefficient = 0.55; 95% CI = 0.15, 0.95; P‐value = 0.008) and AAT concentrations (Coefficient = 0.34; 95% CI = 0.04, 0.63; P‐value = 0.03). This evidence concerns the gene SERPINA1 and giardiasis.