Team members of the Stop Transmission of Polio (STOP) initiative in Uttar Pradesh, northern India. This 2000 photograph depicts a number of female Indian Health Care Workers gathering together prior to immunizing local residents with polio vaccine. Since its inception in the fall of 1998, the STOP Teams have worked in over 50 countries. In the first years of the program, most STOP team members worked primarily to bolster acute flaccid paralysis (AFP) surveillance, support "national immunization" days, and conduct polio case investigation and follow-up. STOP team members are recruited and trained primarily by CDC, however, once on assignment, they are under the supervision of either WHO or UNICEF. STOP assignments require highly qualified public health professionals. The minimum qualification to be considered for a STOP assignment is at least five years of relevant public health work experience. Relevant experience is defined as having worked (school work/internships not included) in one or more of the following areas of public health: communicable disease surveillance (e.g., acute flaccid paralysis surveillance), field epidemiology (e.g., case outbreak investigations), and immunization programs (e.g., developing, implementing, and monitoring programs).