A house in Uttar Pradesh in northern India. The STOP Initiative was part of the Stop Polio Campaign of 2000, which was a global effort to eradicate polio, and was the largest public health initiative in history. The initiative was established in 1988 by the World Health Assembly with its main goal being that of the eradication of polio, while strengthening the worldwide capacity to control other major childhood diseases. Following each national immunization day, health workers visited each home in a given district, in order to verify that all children under 5 years of age had received the polio vaccine. Written outside the door of this house were the dates indicating when the home had been visited, and that the children had been properly immunized. Since the inception of the STOP program in the fall of 1998, STOP Teams have worked in over 50 countries. In the first years of the program, most STOP Team members worked primarily to strengthen acute flaccid paralysis (AFP) surveillance, support "national immunization" days, and conduct polio case investigation with follow-up. Team members are recruited and trained primarily by CDC, and once on assignment they are under the supervision of either WHO, or UNICEF.