Prior to April 3, 2020 the role of the stockpile was to support state, local, tribal, and territorial responders providing potentially life-saving pharmaceuticals and medical supplies for use in a public health emergency severe enough to cause local supplies to run out. Its current role is to act as a national supplement of medicine and medical equipment to a State's supplies, acting as a "stopgap buffer" when "the immediate supply of adequate amounts of these materials may not be immediately available."