"Government representatives are meeting in Geneva this week to decide whether to introduce a global ban on mercury that could include thiomersal, a mercury-based preservative that has been used in some vaccine manufacturing since the 1930s to prevent bacterial or fungal contamination of multidose vials of vaccine," Seth Berkley, a medical epidemiologist and chief executive of the GAVI Alliance, writes in a New York Times opinion piece. "Despite the ominous connotations of mercury, the decision should in theory be a no-brainer: The scientific and medical consensus is that thiomersal poses no human health risk, and that rather than saving lives, a ban would put millions of the world's poorest children at risk of deadly diseases by disrupting vaccination programs," he continues. Switching to single dose vials would be costly and impractical, and "[i]n the absence of any alternative preservative, far fewer vaccines would reach children in developing countries," he states.