Children's Health Defense is an American 501c3 nonprofit advocacy organization, known for its anti-vaccine activism. According to Seth Mnookin, much of the material put forth by the organization involves misinformation on vaccines and anti-vaccine propaganda. It was founded and is chaired by Robert F. Kennedy Jr. Established under the name World Mercury Project in 2016, it has been campaigning against various public health programs, such as vaccination and fluoridation of drinking water. The group has been contributing to vaccine hesitancy in the United States, encouraging citizens and legislators to support anti-vaccine regulations and legislation. Arguments against vaccination are contradicted by overwhelming scientific consensus about the safety and effectiveness of vaccines.