"Thanks to a herculean effort by health advocates, 78 percent of children in low-income countries receive the basic set of childhood vaccines, covering diphtheria, tetanus, pertussis, hepatitis B and haemophilus influenza," a Bloomberg View editorial states. However, "[t]his campaign will be disrupted, and lives lost, if immunization critics win their latest battle for an international ban on a vaccine component" -- thimerosal, a mercury-containing organic compound -- "that has proved to be safe time and time again," the editorial writes, noting, "Groups such as the Coalition for Mercury-Free Drugs and the Coalition for SafeMinds are pressing their case before the United Nations Environmental Program [UNEP] meets on Jan. 13 to prepare a global treaty reducing mercury use."