Dr. Van Driest and colleagues at Vanderbilt have demonstrated that 40% of children treated with a proton pump inhibitor – among the most commonly used drugs, often for gastroesophageal reflux disease – were at a higher risk of infection related to being the CYP2C19 normal metabolizer phenotype, having double the infection rate of children who were rapid or ultrarapid metabolizers (Bernal et al., 2019). This evidence concerns the gene CYP2C19 and infection.